Imaging

With the help of artificial intelligence (AI), arterial inflammation measured with coronary computed tomography angiography (CCTA) can predict fatal and nonfatal events in patients with nonobstructive coronary artery disease (CAD), according to a study that suggests this approach would change treatment about half the time.

In patients with nonobstructive CAD, CCTA measurement of inflammation on the basis of the Fat Attenuation Index (FAI) “predicts fatal and nonfatal cardiac events independently from clinical risk scores and routine CCTA interpretation,” reported Charalambos Antoniades, MD, PhD, professor of cardiology, Radcliffe Department of Medicine, Oxford, England.

This analysis was based on data from ORFAN, an ongoing study that expects to eventually collect data from 250,000 CCTA. There were multiple goals. The first was to evaluate whether there is a need and a role of CCTA to risk stratify patients without obstructive CAD. A second objective was to evaluate if the FAI inflammation score can quantify residual risk in these patients.

Ted Bosworth/MDedge News

Based on the answers to these questions, the investigators then proceeded to determine if an AI risk model that combines data from the FAI score and risk factors is widely generalizable and, in addition, whether it reclassifies patients in a way meaningful to management.
 

CCTA-based inflammation is promising

The answers to all these questions were yes, according to data presented by Dr. Antoniades in a late-breaker at the American Heart Association scientific sessions.

So far, ORPHAN, which has multiple participating sites in the United Kingdom, Europe, United States, South America, Asia, and Australia, have data on more than 100,000 CCTAs. Approximately 40,000 have been processed. Of these, 82% have had nonobstructive CAD and the remaining obstructive disease.

In long-term follow-up, the numbers of major adverse cardiovascular events (MACE) and cardiac deaths were compared in these two groups. In absolute terms, the nonobstructive CAD group had about twice as many MACE (2,587 vs. 1,450) and cardiac deaths (1,118 vs. 636).

The rate of these events was much lower in the nonobstructive group , which had four times more patients than the obstructive group, but Dr. Antoniades said these data demonstrate substantial rates of events in the nonobstructive group as well as an unmet need to identify and treat risk associated with nonobstructive CAD.

When determining if coronary inflammation as measured with CCTA could be a means identifying risk independent of other factors, the FAI scores were evaluated by quartile in a nested cohort of 3,666 consecutive patients. FAI, which has been validated, is calculated with spatial changes in CCTA-measured perivascular fat composition after standardization for anatomy and other variables.

The discrimination for risk with FAI was impressive. When evaluated across all patients (obstructive or nonobstructive CAD), those in the highest FAI quartile had a hazard ratio (HR) for MACE that was more than six times higher (HR 6.76; P < .001) and a risk of cardiac mortality that was more than 20 times higher (HR 20.20; P < .001) than that of those in the first quartile.

“The prediction was independent of all other risk factors,” Dr. Antoniades reported.
 

Predictive value greater in nonobstructive CAD

When evaluated in nonobstructive disease, the predictive value of FAI was even greater. In obstructive CAD patients, the increased risk of MACE for the fourth relative to the first quartile was increased threefold (HR 3.15; P < .001), but it was increased almost fivefold among those with nonobstructive CAD (HR 4.77; P < .001). The increases for cardiac mortality were fivefold (HR 5.15; P < .001) and more than 10-fold (HR 10.49; P < .001) in these groups, respectively.

When a risk model based on AI that incorporated FAI plus other cardiovascular risk factors was applied retrospectively to the ORPHAN data, the predicted and actual event graph lines were nearly superimposable over a follow-up to 10 years at risk levels ranging from low to very high.

When this inflammation-based AI model was evaluated against standard risk prediction in patients with nonobstructive CAD, 30% of patients were reclassified to a higher risk category and 10% to a lower risk category.

When the AI-risk calculations were provided to clinicians at four hospitals over a recent 1-year period, it resulted “in changes of management in approximately half of patients,” Dr. Antoniades said.

Overall, Dr. Antoniades said these data provide evidence that coronary inflammation is an important driver of residual risk in patients who have nonobstructive CAD on CCTA, and he believes that the AI-enhanced interpretation of the FAI-based inflammatory burden has the potential to become an important management tool.

“AI-risk assessment may transform risk stratification and management of patients undergoing routine CCTA,” Dr. Antoniades said.
 

Imaging has potential for expanded risk assessment

The AHA-invited discussant, Viviany R. Taqueti, MD, director of the cardiac stress laboratory at Brigham and Women’s Hospital, Boston, agreed with the promise of evaluating inflammatory infiltrate in the coronary arteries as well as looking at fat in other tissues, such as skeletal muscle, to better risk stratify patients, but she cautioned about the limitations of conclusions based on observational data.

“A registry is not a randomized trial,” she said.

Characterizing AI as a “black box” in terms of understanding methodology, she also recommended further studies to validate the relative contribution of AI to inflammation alone in risk stratification.

Still, she believes that the “explosive growth” in imaging has created new opportunities for more precisely evaluating cardiovascular risk. She said these might be particularly helpful in the context of the “changing landscape” in CAD driven by less smoking, more obesity, and increased statin use. Overall, she endorsed the basic questions Dr. Antoniades is exploring.

“This is an incredibly intriguing idea that deserves continuing research,” she said.

Dr. Antoniades reported financial relationships with Amarin, AstraZeneca, Caristo Diagnostics, Covance, Mitsubishi Tanabe, MedImmune, Novo Nordisk, Sanofi, and Silence Therapeutics. Dr. Taqueti reported no potential conflicts of interest.

With the help of artificial intelligence (AI), arterial inflammation measured with coronary computed tomography angiography (CCTA) can predict fatal and nonfatal events in patients with nonobstructive coronary artery disease (CAD), according to a study that suggests this approach would change treatment about half the time.

In patients with nonobstructive CAD, CCTA measurement of inflammation on the basis of the Fat Attenuation Index (FAI) “predicts fatal and nonfatal cardiac events independently from clinical risk scores and routine CCTA interpretation,” reported Charalambos Antoniades, MD, PhD, professor of cardiology, Radcliffe Department of Medicine, Oxford, England.

This analysis was based on data from ORFAN, an ongoing study that expects to eventually collect data from 250,000 CCTA. There were multiple goals. The first was to evaluate whether there is a need and a role of CCTA to risk stratify patients without obstructive CAD. A second objective was to evaluate if the FAI inflammation score can quantify residual risk in these patients.

Ted Bosworth/MDedge News

Based on the answers to these questions, the investigators then proceeded to determine if an AI risk model that combines data from the FAI score and risk factors is widely generalizable and, in addition, whether it reclassifies patients in a way meaningful to management.
 

CCTA-based inflammation is promising

The answers to all these questions were yes, according to data presented by Dr. Antoniades in a late-breaker at the American Heart Association scientific sessions.

So far, ORPHAN, which has multiple participating sites in the United Kingdom, Europe, United States, South America, Asia, and Australia, have data on more than 100,000 CCTAs. Approximately 40,000 have been processed. Of these, 82% have had nonobstructive CAD and the remaining obstructive disease.

In long-term follow-up, the numbers of major adverse cardiovascular events (MACE) and cardiac deaths were compared in these two groups. In absolute terms, the nonobstructive CAD group had about twice as many MACE (2,587 vs. 1,450) and cardiac deaths (1,118 vs. 636).

The rate of these events was much lower in the nonobstructive group , which had four times more patients than the obstructive group, but Dr. Antoniades said these data demonstrate substantial rates of events in the nonobstructive group as well as an unmet need to identify and treat risk associated with nonobstructive CAD.

When determining if coronary inflammation as measured with CCTA could be a means identifying risk independent of other factors, the FAI scores were evaluated by quartile in a nested cohort of 3,666 consecutive patients. FAI, which has been validated, is calculated with spatial changes in CCTA-measured perivascular fat composition after standardization for anatomy and other variables.

The discrimination for risk with FAI was impressive. When evaluated across all patients (obstructive or nonobstructive CAD), those in the highest FAI quartile had a hazard ratio (HR) for MACE that was more than six times higher (HR 6.76; P < .001) and a risk of cardiac mortality that was more than 20 times higher (HR 20.20; P < .001) than that of those in the first quartile.

“The prediction was independent of all other risk factors,” Dr. Antoniades reported.
 

Predictive value greater in nonobstructive CAD

When evaluated in nonobstructive disease, the predictive value of FAI was even greater. In obstructive CAD patients, the increased risk of MACE for the fourth relative to the first quartile was increased threefold (HR 3.15; P < .001), but it was increased almost fivefold among those with nonobstructive CAD (HR 4.77; P < .001). The increases for cardiac mortality were fivefold (HR 5.15; P < .001) and more than 10-fold (HR 10.49; P < .001) in these groups, respectively.

When a risk model based on AI that incorporated FAI plus other cardiovascular risk factors was applied retrospectively to the ORPHAN data, the predicted and actual event graph lines were nearly superimposable over a follow-up to 10 years at risk levels ranging from low to very high.

When this inflammation-based AI model was evaluated against standard risk prediction in patients with nonobstructive CAD, 30% of patients were reclassified to a higher risk category and 10% to a lower risk category.

When the AI-risk calculations were provided to clinicians at four hospitals over a recent 1-year period, it resulted “in changes of management in approximately half of patients,” Dr. Antoniades said.

Overall, Dr. Antoniades said these data provide evidence that coronary inflammation is an important driver of residual risk in patients who have nonobstructive CAD on CCTA, and he believes that the AI-enhanced interpretation of the FAI-based inflammatory burden has the potential to become an important management tool.

“AI-risk assessment may transform risk stratification and management of patients undergoing routine CCTA,” Dr. Antoniades said.
 

Imaging has potential for expanded risk assessment

The AHA-invited discussant, Viviany R. Taqueti, MD, director of the cardiac stress laboratory at Brigham and Women’s Hospital, Boston, agreed with the promise of evaluating inflammatory infiltrate in the coronary arteries as well as looking at fat in other tissues, such as skeletal muscle, to better risk stratify patients, but she cautioned about the limitations of conclusions based on observational data.

“A registry is not a randomized trial,” she said.

Characterizing AI as a “black box” in terms of understanding methodology, she also recommended further studies to validate the relative contribution of AI to inflammation alone in risk stratification.

Still, she believes that the “explosive growth” in imaging has created new opportunities for more precisely evaluating cardiovascular risk. She said these might be particularly helpful in the context of the “changing landscape” in CAD driven by less smoking, more obesity, and increased statin use. Overall, she endorsed the basic questions Dr. Antoniades is exploring.

“This is an incredibly intriguing idea that deserves continuing research,” she said.

Dr. Antoniades reported financial relationships with Amarin, AstraZeneca, Caristo Diagnostics, Covance, Mitsubishi Tanabe, MedImmune, Novo Nordisk, Sanofi, and Silence Therapeutics. Dr. Taqueti reported no potential conflicts of interest.

With the help of artificial intelligence (AI), arterial inflammation measured with coronary computed tomography angiography (CCTA) can predict fatal and nonfatal events in patients with nonobstructive coronary artery disease (CAD), according to a study that suggests this approach would change treatment about half the time.

In patients with nonobstructive CAD, CCTA measurement of inflammation on the basis of the Fat Attenuation Index (FAI) “predicts fatal and nonfatal cardiac events independently from clinical risk scores and routine CCTA interpretation,” reported Charalambos Antoniades, MD, PhD, professor of cardiology, Radcliffe Department of Medicine, Oxford, England.

This analysis was based on data from ORFAN, an ongoing study that expects to eventually collect data from 250,000 CCTA. There were multiple goals. The first was to evaluate whether there is a need and a role of CCTA to risk stratify patients without obstructive CAD. A second objective was to evaluate if the FAI inflammation score can quantify residual risk in these patients.

Ted Bosworth/MDedge News

Based on the answers to these questions, the investigators then proceeded to determine if an AI risk model that combines data from the FAI score and risk factors is widely generalizable and, in addition, whether it reclassifies patients in a way meaningful to management.
 

CCTA-based inflammation is promising

The answers to all these questions were yes, according to data presented by Dr. Antoniades in a late-breaker at the American Heart Association scientific sessions.

So far, ORPHAN, which has multiple participating sites in the United Kingdom, Europe, United States, South America, Asia, and Australia, have data on more than 100,000 CCTAs. Approximately 40,000 have been processed. Of these, 82% have had nonobstructive CAD and the remaining obstructive disease.

In long-term follow-up, the numbers of major adverse cardiovascular events (MACE) and cardiac deaths were compared in these two groups. In absolute terms, the nonobstructive CAD group had about twice as many MACE (2,587 vs. 1,450) and cardiac deaths (1,118 vs. 636).

The rate of these events was much lower in the nonobstructive group , which had four times more patients than the obstructive group, but Dr. Antoniades said these data demonstrate substantial rates of events in the nonobstructive group as well as an unmet need to identify and treat risk associated with nonobstructive CAD.

When determining if coronary inflammation as measured with CCTA could be a means identifying risk independent of other factors, the FAI scores were evaluated by quartile in a nested cohort of 3,666 consecutive patients. FAI, which has been validated, is calculated with spatial changes in CCTA-measured perivascular fat composition after standardization for anatomy and other variables.

The discrimination for risk with FAI was impressive. When evaluated across all patients (obstructive or nonobstructive CAD), those in the highest FAI quartile had a hazard ratio (HR) for MACE that was more than six times higher (HR 6.76; P < .001) and a risk of cardiac mortality that was more than 20 times higher (HR 20.20; P < .001) than that of those in the first quartile.

“The prediction was independent of all other risk factors,” Dr. Antoniades reported.
 

Predictive value greater in nonobstructive CAD

When evaluated in nonobstructive disease, the predictive value of FAI was even greater. In obstructive CAD patients, the increased risk of MACE for the fourth relative to the first quartile was increased threefold (HR 3.15; P < .001), but it was increased almost fivefold among those with nonobstructive CAD (HR 4.77; P < .001). The increases for cardiac mortality were fivefold (HR 5.15; P < .001) and more than 10-fold (HR 10.49; P < .001) in these groups, respectively.

When a risk model based on AI that incorporated FAI plus other cardiovascular risk factors was applied retrospectively to the ORPHAN data, the predicted and actual event graph lines were nearly superimposable over a follow-up to 10 years at risk levels ranging from low to very high.

When this inflammation-based AI model was evaluated against standard risk prediction in patients with nonobstructive CAD, 30% of patients were reclassified to a higher risk category and 10% to a lower risk category.

When the AI-risk calculations were provided to clinicians at four hospitals over a recent 1-year period, it resulted “in changes of management in approximately half of patients,” Dr. Antoniades said.

Overall, Dr. Antoniades said these data provide evidence that coronary inflammation is an important driver of residual risk in patients who have nonobstructive CAD on CCTA, and he believes that the AI-enhanced interpretation of the FAI-based inflammatory burden has the potential to become an important management tool.

“AI-risk assessment may transform risk stratification and management of patients undergoing routine CCTA,” Dr. Antoniades said.
 

Imaging has potential for expanded risk assessment

The AHA-invited discussant, Viviany R. Taqueti, MD, director of the cardiac stress laboratory at Brigham and Women’s Hospital, Boston, agreed with the promise of evaluating inflammatory infiltrate in the coronary arteries as well as looking at fat in other tissues, such as skeletal muscle, to better risk stratify patients, but she cautioned about the limitations of conclusions based on observational data.

“A registry is not a randomized trial,” she said.

Characterizing AI as a “black box” in terms of understanding methodology, she also recommended further studies to validate the relative contribution of AI to inflammation alone in risk stratification.

Still, she believes that the “explosive growth” in imaging has created new opportunities for more precisely evaluating cardiovascular risk. She said these might be particularly helpful in the context of the “changing landscape” in CAD driven by less smoking, more obesity, and increased statin use. Overall, she endorsed the basic questions Dr. Antoniades is exploring.

“This is an incredibly intriguing idea that deserves continuing research,” she said.

Dr. Antoniades reported financial relationships with Amarin, AstraZeneca, Caristo Diagnostics, Covance, Mitsubishi Tanabe, MedImmune, Novo Nordisk, Sanofi, and Silence Therapeutics. Dr. Taqueti reported no potential conflicts of interest.

PHILADELPHIA – An artificial intelligence platform that sends alerts based on electrocardiography results enabled cardiologists and emergency department physicians at a major hospital in Taiwan to move patients with ST-elevation myocardial infarction (STEMI) into the catheterization laboratory 9 minutes sooner than the conventional protocol that did not use AI.

“This is the first randomized clinical trial to demonstrate the reduction of electrocardiography to coronary cath lab activation time" from 52.3 to 43.3 minutes (P = .003), Chin Sheng Lin, MD, PhD, director of cardiology at the National Defense Medical Center Tri-Service General Hospital in Taipei City, said in presenting the results at the American Heart Association scientific sessions.

AHA/Scott Morgan

Dr. Lin reported results from the Artificial Intelligence Enabled Rapid Identify of ST-Elevation Myocardial Infarction Using Electrocardiogram (ARISE) trial. The trial included 43,994 patients who came to the hospital’s emergency and inpatient departments with at least one ECG but no history of coronary angiography (CAG) in the previous 3 days between May 2022 and April 2023.

They were randomly assigned by date to either AI-ECG for rapid identification and triage of STEMI or standard care. Overall, 145 patients were finally diagnosed with STEMI based on CAG, 77 in the intervention group and 68 in the control group. All patients were seen by one of 20 cardiologists who participated in the study.

Dr. Lin and his group developed an AI algorithm that captures the ECG readout in the emergency department, analyzes the data and then sends a high-risk alarm to the front-line physician and on-duty cardiologist to activate the primary percutaneous coronary intervention (PCI).
 

Trial results

The differentiation between groups was even more pronounced in ED patients during regular working hours, Dr. Lin said, at 61.6 minutes for the intervention group vs. 33.1 minutes for controls (P = .001).*

He noted that the AI group showed a trend towards fewer cases of clinically suspected STEMI but not getting CAG, 6.5% vs. 15.8%, for an odds ratio of 0.37 (95% confidence interval, 0.14-0.94).

The AI-ECG model also demonstrated a high diagnostic accuracy. “With this AI-ECG system, because it has a very high accuracy and a high positive predictive variable that reach 88%, we can send a message to the on-duty cardiologists and also the emergency room physician and they can send the patients to receive the operation or the PCI as soon as possible,” Dr. Lin said in an interview.

The time differential is critical, Dr. Lin said. “For the patient with acute myocardial infarction, 1 minute is critical, because the patients can die within minutes,” he said. “If we can save 9 minutes I think we can save more lives, but it needs a larger study to evaluate that.”

Dr. Lin acknowledged a few limitations with the trial, among them its single-center nature, relatively small sample size of STEMI patients and the short-term of follow-up. Future study should involve multiple centers along with a prehospital, emergency medical services AI-ECG model.
 

‘Novel’ for an AI trial

“This is an incredible application of an AI technology in a real-world problem,” said Brahmajee K. Nallamothu, MD, MPH, an interventional cardiologist at the University of Michigan, Ann Arbor, who did not participate in the study. “What I really love about this study is it’s actually a clinical problem that has large implications, particularly for under-resourced areas.”

AHA/Scott Morgan

Using a randomized clinical trial to evaluate the AI platform is “very, very novel,” he said, and called the time improvement “enormous.” Referencing Dr. Lin’s next steps for studying the AI-ECG platform, Dr. Nallamothu said, “if we could push this up even earlier to paramedics and EMTs and prehospital systems, there would be a lot of excitement there.”

He noted the sensitivity analysis resulted in a rate of 88.8% along with the positive predictive value of 88%. “Missing 1 out of 10 ST-elevation MIs in my eyes can still be considered a big deal, so we need to know if this is happening in particular types of patients, for example women versus men, or other groups.”

However, some investigations reported false activation rates as high as 33%, he said. “So, to say that, the positive predictive value is at 88% is really exciting and I think it can make a real inroads,” Dr. Nallamothu said.

Dr. Lin and Dr. Nallamothu have no relevant disclosures.

*Correction, 11/20/23: An earlier version of this article misstated in both trial arms the time to coronary catheterization lab activation.

PHILADELPHIA – An artificial intelligence platform that sends alerts based on electrocardiography results enabled cardiologists and emergency department physicians at a major hospital in Taiwan to move patients with ST-elevation myocardial infarction (STEMI) into the catheterization laboratory 9 minutes sooner than the conventional protocol that did not use AI.

“This is the first randomized clinical trial to demonstrate the reduction of electrocardiography to coronary cath lab activation time" from 52.3 to 43.3 minutes (P = .003), Chin Sheng Lin, MD, PhD, director of cardiology at the National Defense Medical Center Tri-Service General Hospital in Taipei City, said in presenting the results at the American Heart Association scientific sessions.

AHA/Scott Morgan

Dr. Lin reported results from the Artificial Intelligence Enabled Rapid Identify of ST-Elevation Myocardial Infarction Using Electrocardiogram (ARISE) trial. The trial included 43,994 patients who came to the hospital’s emergency and inpatient departments with at least one ECG but no history of coronary angiography (CAG) in the previous 3 days between May 2022 and April 2023.

They were randomly assigned by date to either AI-ECG for rapid identification and triage of STEMI or standard care. Overall, 145 patients were finally diagnosed with STEMI based on CAG, 77 in the intervention group and 68 in the control group. All patients were seen by one of 20 cardiologists who participated in the study.

Dr. Lin and his group developed an AI algorithm that captures the ECG readout in the emergency department, analyzes the data and then sends a high-risk alarm to the front-line physician and on-duty cardiologist to activate the primary percutaneous coronary intervention (PCI).
 

Trial results

The differentiation between groups was even more pronounced in ED patients during regular working hours, Dr. Lin said, at 61.6 minutes for the intervention group vs. 33.1 minutes for controls (P = .001).*

He noted that the AI group showed a trend towards fewer cases of clinically suspected STEMI but not getting CAG, 6.5% vs. 15.8%, for an odds ratio of 0.37 (95% confidence interval, 0.14-0.94).

The AI-ECG model also demonstrated a high diagnostic accuracy. “With this AI-ECG system, because it has a very high accuracy and a high positive predictive variable that reach 88%, we can send a message to the on-duty cardiologists and also the emergency room physician and they can send the patients to receive the operation or the PCI as soon as possible,” Dr. Lin said in an interview.

The time differential is critical, Dr. Lin said. “For the patient with acute myocardial infarction, 1 minute is critical, because the patients can die within minutes,” he said. “If we can save 9 minutes I think we can save more lives, but it needs a larger study to evaluate that.”

Dr. Lin acknowledged a few limitations with the trial, among them its single-center nature, relatively small sample size of STEMI patients and the short-term of follow-up. Future study should involve multiple centers along with a prehospital, emergency medical services AI-ECG model.
 

‘Novel’ for an AI trial

“This is an incredible application of an AI technology in a real-world problem,” said Brahmajee K. Nallamothu, MD, MPH, an interventional cardiologist at the University of Michigan, Ann Arbor, who did not participate in the study. “What I really love about this study is it’s actually a clinical problem that has large implications, particularly for under-resourced areas.”

AHA/Scott Morgan

Using a randomized clinical trial to evaluate the AI platform is “very, very novel,” he said, and called the time improvement “enormous.” Referencing Dr. Lin’s next steps for studying the AI-ECG platform, Dr. Nallamothu said, “if we could push this up even earlier to paramedics and EMTs and prehospital systems, there would be a lot of excitement there.”

He noted the sensitivity analysis resulted in a rate of 88.8% along with the positive predictive value of 88%. “Missing 1 out of 10 ST-elevation MIs in my eyes can still be considered a big deal, so we need to know if this is happening in particular types of patients, for example women versus men, or other groups.”

However, some investigations reported false activation rates as high as 33%, he said. “So, to say that, the positive predictive value is at 88% is really exciting and I think it can make a real inroads,” Dr. Nallamothu said.

Dr. Lin and Dr. Nallamothu have no relevant disclosures.

*Correction, 11/20/23: An earlier version of this article misstated in both trial arms the time to coronary catheterization lab activation.

PHILADELPHIA – An artificial intelligence platform that sends alerts based on electrocardiography results enabled cardiologists and emergency department physicians at a major hospital in Taiwan to move patients with ST-elevation myocardial infarction (STEMI) into the catheterization laboratory 9 minutes sooner than the conventional protocol that did not use AI.

“This is the first randomized clinical trial to demonstrate the reduction of electrocardiography to coronary cath lab activation time" from 52.3 to 43.3 minutes (P = .003), Chin Sheng Lin, MD, PhD, director of cardiology at the National Defense Medical Center Tri-Service General Hospital in Taipei City, said in presenting the results at the American Heart Association scientific sessions.

AHA/Scott Morgan

Dr. Lin reported results from the Artificial Intelligence Enabled Rapid Identify of ST-Elevation Myocardial Infarction Using Electrocardiogram (ARISE) trial. The trial included 43,994 patients who came to the hospital’s emergency and inpatient departments with at least one ECG but no history of coronary angiography (CAG) in the previous 3 days between May 2022 and April 2023.

They were randomly assigned by date to either AI-ECG for rapid identification and triage of STEMI or standard care. Overall, 145 patients were finally diagnosed with STEMI based on CAG, 77 in the intervention group and 68 in the control group. All patients were seen by one of 20 cardiologists who participated in the study.

Dr. Lin and his group developed an AI algorithm that captures the ECG readout in the emergency department, analyzes the data and then sends a high-risk alarm to the front-line physician and on-duty cardiologist to activate the primary percutaneous coronary intervention (PCI).
 

Trial results

The differentiation between groups was even more pronounced in ED patients during regular working hours, Dr. Lin said, at 61.6 minutes for the intervention group vs. 33.1 minutes for controls (P = .001).*

He noted that the AI group showed a trend towards fewer cases of clinically suspected STEMI but not getting CAG, 6.5% vs. 15.8%, for an odds ratio of 0.37 (95% confidence interval, 0.14-0.94).

The AI-ECG model also demonstrated a high diagnostic accuracy. “With this AI-ECG system, because it has a very high accuracy and a high positive predictive variable that reach 88%, we can send a message to the on-duty cardiologists and also the emergency room physician and they can send the patients to receive the operation or the PCI as soon as possible,” Dr. Lin said in an interview.

The time differential is critical, Dr. Lin said. “For the patient with acute myocardial infarction, 1 minute is critical, because the patients can die within minutes,” he said. “If we can save 9 minutes I think we can save more lives, but it needs a larger study to evaluate that.”

Dr. Lin acknowledged a few limitations with the trial, among them its single-center nature, relatively small sample size of STEMI patients and the short-term of follow-up. Future study should involve multiple centers along with a prehospital, emergency medical services AI-ECG model.
 

‘Novel’ for an AI trial

“This is an incredible application of an AI technology in a real-world problem,” said Brahmajee K. Nallamothu, MD, MPH, an interventional cardiologist at the University of Michigan, Ann Arbor, who did not participate in the study. “What I really love about this study is it’s actually a clinical problem that has large implications, particularly for under-resourced areas.”

AHA/Scott Morgan

Using a randomized clinical trial to evaluate the AI platform is “very, very novel,” he said, and called the time improvement “enormous.” Referencing Dr. Lin’s next steps for studying the AI-ECG platform, Dr. Nallamothu said, “if we could push this up even earlier to paramedics and EMTs and prehospital systems, there would be a lot of excitement there.”

He noted the sensitivity analysis resulted in a rate of 88.8% along with the positive predictive value of 88%. “Missing 1 out of 10 ST-elevation MIs in my eyes can still be considered a big deal, so we need to know if this is happening in particular types of patients, for example women versus men, or other groups.”

However, some investigations reported false activation rates as high as 33%, he said. “So, to say that, the positive predictive value is at 88% is really exciting and I think it can make a real inroads,” Dr. Nallamothu said.

Dr. Lin and Dr. Nallamothu have no relevant disclosures.

*Correction, 11/20/23: An earlier version of this article misstated in both trial arms the time to coronary catheterization lab activation.

The emerging advantages of PET myocardial perfusion imaging (MPI) for coronary artery disease (CAD) diagnosis and assessment of cardiovascular event risk has prompted growing use of this technology as an alternative to the more commonly used single photon–emission CT (SPECT) MPI.

The advantages of PET MPI include better diagnostic performance and shorter acquisition times. The latest position statement from the American Society of Nuclear Cardiology and Society of Nuclear Medicine and Molecular Imaging highlights these advantages and pinpoints additional important properties of PET, including consistent, high-quality images and low radiation exposure. It also allows quantification of myocardial blood flow, and it has “strong prognostic power.”
 

Tracer availability

Despite these advantages, that position paper and subsequent studies note that PET MPI has been underutilized in the United States, largely owing to issues with the available tracers, which have characteristics that limit widespread use in the clinic.

Rubidium, arguably the most commonly used tracer for PET MPI, is not available in unit dosing and so can be expensive for low-volume centers, plus it also requires an on-site generator, Michael Salerno, MD, PhD, a member of the American College of Cardiology’s Imaging Council and section chief of cardiovascular imaging, Stanford (Calif.) University, told this news organization.

N-ammonia, the other U.S. Food and Drug Administration–approved tracer, is available in unit dosing, but its short half-life means that centers need an onsite cyclotron, Dr. Salerno said.

For cardiac perfusion imaging and myocardial blood flow (MBF) quantification, 15O-water is considered the gold standard, although it’s not approved by the FDA. This tracer also requires an on-site cyclotron and “is challenging to use,” Dr. Salerno said. Use has been largely restricted to research purposes, though efforts are underway to widen its availability.

Enter flurpiridaz F-18 (GE Healthcare), a novel PET MPI tracer labeled with fluorine-18. Its longer half-life – similar to that of fluorodeoxyglucose, a tracer used to detect various cancers – could broaden the number of sites that could perform perfusion PET studies, Dr. Salerno said.

“Flurpiridaz also is supposed to have a more linear relationship between flow and tracer uptake, which could improve the ability to perform quantification of perfusion,” he noted. “It also offers the ability to do exercise PET, which is impossible for rubidium and challenging for ammonia, given its 11-minute half-life.”
 

Flurpiridaz status

The FDA requires two phase-3 studies that show safety and sufficient diagnostic performance before it will approve a new tracer. The first required study, published in the Journal of the American College of Cardiology, showed that the tracer’s sensitivity for detection of greater than or equal to 50% stenosis by ICA was significantly higher than SPECT; however, the specificity did not meet the prespecified noninferiority criterion.

The second FDA-required study, published online recently, also in the Journal of the American College of Cardiology, was designed differently from the first in that only patients with suspected – not known – CAD were enrolled. The primary efficacy endpoint was sensitivity and specificity of flurpiridaz PET for overall detection of CAD, rather than comparing it to SPECT MPI (which became a secondary endpoint). PET and SPECT studies were both performed before invasive coronary angiography to minimize referral bias; SPECT studies included cadmium zinc telluride cameras.

In that study, which included 578 patients (mean age, 64; 32.5% women) from 48 centers in the United States, Canada, and Europe, flurpiridaz met the efficacy endpoints: Its sensitivity and specificity were significantly higher than the prespecified threshold value by two of the three readers; its sensitivity was higher than SPECT (80.3% vs. 68.7%); and its specificity was noninferior (63.8% vs. 61.7%).

PET areas under the receiver-operating characteristic curves were higher than SPECT in the overall population and in women and obese patients, at half the radiation dose of SPECT.

“Cardiac PET MPI is positioned to serve as the leading modality for the functional evaluation of suspected and known CAD,” Jamieson M. Bourque, MD, MHS, medical director of nuclear cardiology, echocardiography, and the Stress Laboratory, University of Virginia, Charlottesville, wrote in an editorial accompanying the second study . “18F-flurpiridaz will facilitate this upward progression with beneficial tracer characteristics that will increase access and availability, enable exercise stress, and optimize MBF quantification.”

At this point, FDA approval of flurpiridaz is expected sometime in 2024, said James E. Udelson, MD, principal investigator of the recent study, chief of the division of cardiology, and director of the Nuclear Cardiology Laboratory at Tufts University School of Medicine, Boston.
 

Learning curve

Flurpiridaz comes with “a really interesting and important” learning curve, Dr. Udelson said. “The images are really crisp, and they look very different from what most people are used to. The GE folks are going to have to make sure that the American Society of Nuclear Cardiology and other professional societies are tuned in to help in the education part, because it’s not an easy, automatic switch. Very good image readers can adapt, but it’s not just one day you do one, then switch to the other.”

A “somewhat apt” analogy would be the difference between an echocardiogram and an MRI, he explained. “The MRI is much crisper. You’re seeing edges more crisply. You’re seeing the difference between a thicker and a thinner segment of the wall more crisply, and that’s actually real. You can’t say the thinner segment is abnormal; it’s just that you’re seeing it better. So, with this tracer, normal differences in the thickness of a wall can almost look like a defect if you’re not used to knowing that’s the new normal.”

The expected approval of flurpiridaz “will be a win for cardiac PET, broadening the range of sites that could perform PET,” Dr. Salerno commented. “However, it is worth cautioning that all of the prior data with PET using different agents does not necessarily equate to the same performance with the new agent, given that the performance seems to be lower than that shown in prior PET studies using other agents.”

Dr. Salerno would like to see additional studies comparing flurpiridaz with rubidium or ammonia, as well as studies performing quantification with flurpiridaz, “which theoretically should have some advantages,” he said.

Dr. Udelson noted that MedTrace, a company in Denmark, is working on a radiolabeled water tracer based on 15-O-water that is just starting a pivotal trial. Dr. Udelson is a consultant to the company and is a steering committee member for the pivotal trial.

For now, “the big take-home is that there are a lot of ways these days to test people for CAD,” he said. “As the types of things we can do to test people expand, individuals and centers need to make sure they focus on providing any new service, however they do it, with really superb quality and experience.”

“You don’t just do something new because it’s new,” he added. “It has to be done really well. If you do the new thing badly, you’re not going to get better information.”

Dr. Udelson is a consultant and advisory board member for GE Healthcare, a consultant to MedTrace, and a steering committee member for MedTrace’s pivotal trial. Dr. Bourque has served on a GE Healthcare advisory board for amyloid imaging. Dr. Salerno reports no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The emerging advantages of PET myocardial perfusion imaging (MPI) for coronary artery disease (CAD) diagnosis and assessment of cardiovascular event risk has prompted growing use of this technology as an alternative to the more commonly used single photon–emission CT (SPECT) MPI.

The advantages of PET MPI include better diagnostic performance and shorter acquisition times. The latest position statement from the American Society of Nuclear Cardiology and Society of Nuclear Medicine and Molecular Imaging highlights these advantages and pinpoints additional important properties of PET, including consistent, high-quality images and low radiation exposure. It also allows quantification of myocardial blood flow, and it has “strong prognostic power.”
 

Tracer availability

Despite these advantages, that position paper and subsequent studies note that PET MPI has been underutilized in the United States, largely owing to issues with the available tracers, which have characteristics that limit widespread use in the clinic.

Rubidium, arguably the most commonly used tracer for PET MPI, is not available in unit dosing and so can be expensive for low-volume centers, plus it also requires an on-site generator, Michael Salerno, MD, PhD, a member of the American College of Cardiology’s Imaging Council and section chief of cardiovascular imaging, Stanford (Calif.) University, told this news organization.

N-ammonia, the other U.S. Food and Drug Administration–approved tracer, is available in unit dosing, but its short half-life means that centers need an onsite cyclotron, Dr. Salerno said.

For cardiac perfusion imaging and myocardial blood flow (MBF) quantification, 15O-water is considered the gold standard, although it’s not approved by the FDA. This tracer also requires an on-site cyclotron and “is challenging to use,” Dr. Salerno said. Use has been largely restricted to research purposes, though efforts are underway to widen its availability.

Enter flurpiridaz F-18 (GE Healthcare), a novel PET MPI tracer labeled with fluorine-18. Its longer half-life – similar to that of fluorodeoxyglucose, a tracer used to detect various cancers – could broaden the number of sites that could perform perfusion PET studies, Dr. Salerno said.

“Flurpiridaz also is supposed to have a more linear relationship between flow and tracer uptake, which could improve the ability to perform quantification of perfusion,” he noted. “It also offers the ability to do exercise PET, which is impossible for rubidium and challenging for ammonia, given its 11-minute half-life.”
 

Flurpiridaz status

The FDA requires two phase-3 studies that show safety and sufficient diagnostic performance before it will approve a new tracer. The first required study, published in the Journal of the American College of Cardiology, showed that the tracer’s sensitivity for detection of greater than or equal to 50% stenosis by ICA was significantly higher than SPECT; however, the specificity did not meet the prespecified noninferiority criterion.

The second FDA-required study, published online recently, also in the Journal of the American College of Cardiology, was designed differently from the first in that only patients with suspected – not known – CAD were enrolled. The primary efficacy endpoint was sensitivity and specificity of flurpiridaz PET for overall detection of CAD, rather than comparing it to SPECT MPI (which became a secondary endpoint). PET and SPECT studies were both performed before invasive coronary angiography to minimize referral bias; SPECT studies included cadmium zinc telluride cameras.

In that study, which included 578 patients (mean age, 64; 32.5% women) from 48 centers in the United States, Canada, and Europe, flurpiridaz met the efficacy endpoints: Its sensitivity and specificity were significantly higher than the prespecified threshold value by two of the three readers; its sensitivity was higher than SPECT (80.3% vs. 68.7%); and its specificity was noninferior (63.8% vs. 61.7%).

PET areas under the receiver-operating characteristic curves were higher than SPECT in the overall population and in women and obese patients, at half the radiation dose of SPECT.

“Cardiac PET MPI is positioned to serve as the leading modality for the functional evaluation of suspected and known CAD,” Jamieson M. Bourque, MD, MHS, medical director of nuclear cardiology, echocardiography, and the Stress Laboratory, University of Virginia, Charlottesville, wrote in an editorial accompanying the second study . “18F-flurpiridaz will facilitate this upward progression with beneficial tracer characteristics that will increase access and availability, enable exercise stress, and optimize MBF quantification.”

At this point, FDA approval of flurpiridaz is expected sometime in 2024, said James E. Udelson, MD, principal investigator of the recent study, chief of the division of cardiology, and director of the Nuclear Cardiology Laboratory at Tufts University School of Medicine, Boston.
 

Learning curve

Flurpiridaz comes with “a really interesting and important” learning curve, Dr. Udelson said. “The images are really crisp, and they look very different from what most people are used to. The GE folks are going to have to make sure that the American Society of Nuclear Cardiology and other professional societies are tuned in to help in the education part, because it’s not an easy, automatic switch. Very good image readers can adapt, but it’s not just one day you do one, then switch to the other.”

A “somewhat apt” analogy would be the difference between an echocardiogram and an MRI, he explained. “The MRI is much crisper. You’re seeing edges more crisply. You’re seeing the difference between a thicker and a thinner segment of the wall more crisply, and that’s actually real. You can’t say the thinner segment is abnormal; it’s just that you’re seeing it better. So, with this tracer, normal differences in the thickness of a wall can almost look like a defect if you’re not used to knowing that’s the new normal.”

The expected approval of flurpiridaz “will be a win for cardiac PET, broadening the range of sites that could perform PET,” Dr. Salerno commented. “However, it is worth cautioning that all of the prior data with PET using different agents does not necessarily equate to the same performance with the new agent, given that the performance seems to be lower than that shown in prior PET studies using other agents.”

Dr. Salerno would like to see additional studies comparing flurpiridaz with rubidium or ammonia, as well as studies performing quantification with flurpiridaz, “which theoretically should have some advantages,” he said.

Dr. Udelson noted that MedTrace, a company in Denmark, is working on a radiolabeled water tracer based on 15-O-water that is just starting a pivotal trial. Dr. Udelson is a consultant to the company and is a steering committee member for the pivotal trial.

For now, “the big take-home is that there are a lot of ways these days to test people for CAD,” he said. “As the types of things we can do to test people expand, individuals and centers need to make sure they focus on providing any new service, however they do it, with really superb quality and experience.”

“You don’t just do something new because it’s new,” he added. “It has to be done really well. If you do the new thing badly, you’re not going to get better information.”

Dr. Udelson is a consultant and advisory board member for GE Healthcare, a consultant to MedTrace, and a steering committee member for MedTrace’s pivotal trial. Dr. Bourque has served on a GE Healthcare advisory board for amyloid imaging. Dr. Salerno reports no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The emerging advantages of PET myocardial perfusion imaging (MPI) for coronary artery disease (CAD) diagnosis and assessment of cardiovascular event risk has prompted growing use of this technology as an alternative to the more commonly used single photon–emission CT (SPECT) MPI.

The advantages of PET MPI include better diagnostic performance and shorter acquisition times. The latest position statement from the American Society of Nuclear Cardiology and Society of Nuclear Medicine and Molecular Imaging highlights these advantages and pinpoints additional important properties of PET, including consistent, high-quality images and low radiation exposure. It also allows quantification of myocardial blood flow, and it has “strong prognostic power.”
 

Tracer availability

Despite these advantages, that position paper and subsequent studies note that PET MPI has been underutilized in the United States, largely owing to issues with the available tracers, which have characteristics that limit widespread use in the clinic.

Rubidium, arguably the most commonly used tracer for PET MPI, is not available in unit dosing and so can be expensive for low-volume centers, plus it also requires an on-site generator, Michael Salerno, MD, PhD, a member of the American College of Cardiology’s Imaging Council and section chief of cardiovascular imaging, Stanford (Calif.) University, told this news organization.

N-ammonia, the other U.S. Food and Drug Administration–approved tracer, is available in unit dosing, but its short half-life means that centers need an onsite cyclotron, Dr. Salerno said.

For cardiac perfusion imaging and myocardial blood flow (MBF) quantification, 15O-water is considered the gold standard, although it’s not approved by the FDA. This tracer also requires an on-site cyclotron and “is challenging to use,” Dr. Salerno said. Use has been largely restricted to research purposes, though efforts are underway to widen its availability.

Enter flurpiridaz F-18 (GE Healthcare), a novel PET MPI tracer labeled with fluorine-18. Its longer half-life – similar to that of fluorodeoxyglucose, a tracer used to detect various cancers – could broaden the number of sites that could perform perfusion PET studies, Dr. Salerno said.

“Flurpiridaz also is supposed to have a more linear relationship between flow and tracer uptake, which could improve the ability to perform quantification of perfusion,” he noted. “It also offers the ability to do exercise PET, which is impossible for rubidium and challenging for ammonia, given its 11-minute half-life.”
 

Flurpiridaz status

The FDA requires two phase-3 studies that show safety and sufficient diagnostic performance before it will approve a new tracer. The first required study, published in the Journal of the American College of Cardiology, showed that the tracer’s sensitivity for detection of greater than or equal to 50% stenosis by ICA was significantly higher than SPECT; however, the specificity did not meet the prespecified noninferiority criterion.

The second FDA-required study, published online recently, also in the Journal of the American College of Cardiology, was designed differently from the first in that only patients with suspected – not known – CAD were enrolled. The primary efficacy endpoint was sensitivity and specificity of flurpiridaz PET for overall detection of CAD, rather than comparing it to SPECT MPI (which became a secondary endpoint). PET and SPECT studies were both performed before invasive coronary angiography to minimize referral bias; SPECT studies included cadmium zinc telluride cameras.

In that study, which included 578 patients (mean age, 64; 32.5% women) from 48 centers in the United States, Canada, and Europe, flurpiridaz met the efficacy endpoints: Its sensitivity and specificity were significantly higher than the prespecified threshold value by two of the three readers; its sensitivity was higher than SPECT (80.3% vs. 68.7%); and its specificity was noninferior (63.8% vs. 61.7%).

PET areas under the receiver-operating characteristic curves were higher than SPECT in the overall population and in women and obese patients, at half the radiation dose of SPECT.

“Cardiac PET MPI is positioned to serve as the leading modality for the functional evaluation of suspected and known CAD,” Jamieson M. Bourque, MD, MHS, medical director of nuclear cardiology, echocardiography, and the Stress Laboratory, University of Virginia, Charlottesville, wrote in an editorial accompanying the second study . “18F-flurpiridaz will facilitate this upward progression with beneficial tracer characteristics that will increase access and availability, enable exercise stress, and optimize MBF quantification.”

At this point, FDA approval of flurpiridaz is expected sometime in 2024, said James E. Udelson, MD, principal investigator of the recent study, chief of the division of cardiology, and director of the Nuclear Cardiology Laboratory at Tufts University School of Medicine, Boston.
 

Learning curve

Flurpiridaz comes with “a really interesting and important” learning curve, Dr. Udelson said. “The images are really crisp, and they look very different from what most people are used to. The GE folks are going to have to make sure that the American Society of Nuclear Cardiology and other professional societies are tuned in to help in the education part, because it’s not an easy, automatic switch. Very good image readers can adapt, but it’s not just one day you do one, then switch to the other.”

A “somewhat apt” analogy would be the difference between an echocardiogram and an MRI, he explained. “The MRI is much crisper. You’re seeing edges more crisply. You’re seeing the difference between a thicker and a thinner segment of the wall more crisply, and that’s actually real. You can’t say the thinner segment is abnormal; it’s just that you’re seeing it better. So, with this tracer, normal differences in the thickness of a wall can almost look like a defect if you’re not used to knowing that’s the new normal.”

The expected approval of flurpiridaz “will be a win for cardiac PET, broadening the range of sites that could perform PET,” Dr. Salerno commented. “However, it is worth cautioning that all of the prior data with PET using different agents does not necessarily equate to the same performance with the new agent, given that the performance seems to be lower than that shown in prior PET studies using other agents.”

Dr. Salerno would like to see additional studies comparing flurpiridaz with rubidium or ammonia, as well as studies performing quantification with flurpiridaz, “which theoretically should have some advantages,” he said.

Dr. Udelson noted that MedTrace, a company in Denmark, is working on a radiolabeled water tracer based on 15-O-water that is just starting a pivotal trial. Dr. Udelson is a consultant to the company and is a steering committee member for the pivotal trial.

For now, “the big take-home is that there are a lot of ways these days to test people for CAD,” he said. “As the types of things we can do to test people expand, individuals and centers need to make sure they focus on providing any new service, however they do it, with really superb quality and experience.”

“You don’t just do something new because it’s new,” he added. “It has to be done really well. If you do the new thing badly, you’re not going to get better information.”

Dr. Udelson is a consultant and advisory board member for GE Healthcare, a consultant to MedTrace, and a steering committee member for MedTrace’s pivotal trial. Dr. Bourque has served on a GE Healthcare advisory board for amyloid imaging. Dr. Salerno reports no relevant financial relationships.

A version of this article first appeared on Medscape.com.

PET scans may serve as both a diagnostic and prognostic tool in giant cell arteritis (GCA), according to a new study.

In over 100 patients with GCA who underwent 18F-fluorodeoxyglucose PET imaging, those with elevated FDG uptake at diagnosis were more likely to develop thoracic aortic aneurysms.

“PET-CT has an excellent diagnostic accuracy for the diagnosis of GCA, certainly if both extracranial and intracranial vessels were assessed. This study shows that performing PET imaging at diagnosis in patients with GCA may also help estimate the future risk for aortic aneurysm formation,” lead author Lien Moreel, MD, of the department of internal medicine at University Hospitals Leuven (Belgium), wrote in an email. “PET imaging at diagnosis can provide both diagnostic and prognostic information in one imaging tool in patients with GCA.”

Brudersohn/CC BY-SA 3.0/Wikimedia Commons

Previous retrospective studies have found an association between FDG uptake at diagnosis and risk for aortic complications, but “prospective studies confirming these findings are lacking,” the investigators wrote. The study was published online in Annals of Internal Medicine.

In the study, Dr. Moreel and colleagues prospectively followed 106 individuals diagnosed with GCA who received FDG-PET within 3 days after starting glucocorticoids. Patients also had CT imaging at diagnosis and then CT imaging annually for up to 10 years. 

A PET scan was considered positive with an FDG uptake of grade 2 or higher in any of seven vascular regions (thoracic and abdominal aorta, subclavian, axillary, carotid, iliac, and femoral arteries). Researchers also used the results to quantify a total vascular score (TVS). Out of the entire cohort, 75 patients had a positive PET scan result.

These patients had a larger increase in the diameter of the ascending aorta and the descending aorta, as well the volume of thoracic aorta after 5 years, compared with those who had a negative PET scan result. These changes were also associated with higher TVS at diagnosis. Of the 23 patients who developed an aortic aneurysm, 18 had a positive PET scan at diagnosis.

The risk of incident thoracic aortic aneurysms was calculated to be 10 times higher in patients with positive PET scans. Fourteen of the 15 patients (93%) with an incident thoracic aortic aneurysm had positive PET results.

Up to now, “we’ve had no way of predicting which patients might be at risk of this potentially serious complication,” Kenneth Warrington, MD, chair of the department of rheumatology and director of the Vasculitis Clinic at the Mayo Clinic in Rochester, Minn., said in an interview. He was not involved with the research.

He hopes that the findings will help inform clinicians on how patients with GCA should be evaluated and monitored. Although the American College of Rheumatology conditionally recommends noninvasive imaging in patients newly diagnosed with GCA, guidance for follow-up on these patients is less clear.

“There are no clear guidelines, but most clinicians who take care of patients with GCA do obtain imaging periodically,” he said. “There is a lot of variability in the practice in terms of which type of scan is used and how often it’s done.”

Although this study did not specifically look at the benefit of screening patients, “we think that follow-up of aortic dimensions seems to be warranted in GCA patients with a positive PET scan result, especially in those with high intensity and broad extent of vascular inflammation,” Dr. Moreel said. “However, the added value of screening and the interval required should be addressed in future studies.”

Applying this study’s protocol in practice in the United States might be difficult, Dr. Warrington noted, as it can be challenging logistically to get imaging done within 3 days of starting steroids. However, Dr. Moreel said it is possible to delay the start of glucocorticoids until the PET scan is performed in patients without visual symptoms or jaw claudication.

PET scans are also expensive, and it can be difficult to get insurance coverage in the United States. However, other imaging modalities could potentially be used in similar ways, Dr. Warrington said. “One could potentially extrapolate to say that if there is difficulty with accessing PET scan, we could use other modalities like CT or MRI basically to see whether the aorta is inflamed or not.”

Dr. Moreel disclosed no relevant financial relationships. Dr. Warrington has received compensation for consulting activities with Sanofi. Eli Lilly, Kiniksa, and Bristol-Myers Squibb have provided support to the Mayo Clinic for clinical trials related to GCA, of which Dr. Warrington served as subinvestigator.

A version of this article appeared on Medscape.com.

PET scans may serve as both a diagnostic and prognostic tool in giant cell arteritis (GCA), according to a new study.

In over 100 patients with GCA who underwent 18F-fluorodeoxyglucose PET imaging, those with elevated FDG uptake at diagnosis were more likely to develop thoracic aortic aneurysms.

“PET-CT has an excellent diagnostic accuracy for the diagnosis of GCA, certainly if both extracranial and intracranial vessels were assessed. This study shows that performing PET imaging at diagnosis in patients with GCA may also help estimate the future risk for aortic aneurysm formation,” lead author Lien Moreel, MD, of the department of internal medicine at University Hospitals Leuven (Belgium), wrote in an email. “PET imaging at diagnosis can provide both diagnostic and prognostic information in one imaging tool in patients with GCA.”

Brudersohn/CC BY-SA 3.0/Wikimedia Commons

Previous retrospective studies have found an association between FDG uptake at diagnosis and risk for aortic complications, but “prospective studies confirming these findings are lacking,” the investigators wrote. The study was published online in Annals of Internal Medicine.

In the study, Dr. Moreel and colleagues prospectively followed 106 individuals diagnosed with GCA who received FDG-PET within 3 days after starting glucocorticoids. Patients also had CT imaging at diagnosis and then CT imaging annually for up to 10 years. 

A PET scan was considered positive with an FDG uptake of grade 2 or higher in any of seven vascular regions (thoracic and abdominal aorta, subclavian, axillary, carotid, iliac, and femoral arteries). Researchers also used the results to quantify a total vascular score (TVS). Out of the entire cohort, 75 patients had a positive PET scan result.

These patients had a larger increase in the diameter of the ascending aorta and the descending aorta, as well the volume of thoracic aorta after 5 years, compared with those who had a negative PET scan result. These changes were also associated with higher TVS at diagnosis. Of the 23 patients who developed an aortic aneurysm, 18 had a positive PET scan at diagnosis.

The risk of incident thoracic aortic aneurysms was calculated to be 10 times higher in patients with positive PET scans. Fourteen of the 15 patients (93%) with an incident thoracic aortic aneurysm had positive PET results.

Up to now, “we’ve had no way of predicting which patients might be at risk of this potentially serious complication,” Kenneth Warrington, MD, chair of the department of rheumatology and director of the Vasculitis Clinic at the Mayo Clinic in Rochester, Minn., said in an interview. He was not involved with the research.

He hopes that the findings will help inform clinicians on how patients with GCA should be evaluated and monitored. Although the American College of Rheumatology conditionally recommends noninvasive imaging in patients newly diagnosed with GCA, guidance for follow-up on these patients is less clear.

“There are no clear guidelines, but most clinicians who take care of patients with GCA do obtain imaging periodically,” he said. “There is a lot of variability in the practice in terms of which type of scan is used and how often it’s done.”

Although this study did not specifically look at the benefit of screening patients, “we think that follow-up of aortic dimensions seems to be warranted in GCA patients with a positive PET scan result, especially in those with high intensity and broad extent of vascular inflammation,” Dr. Moreel said. “However, the added value of screening and the interval required should be addressed in future studies.”

Applying this study’s protocol in practice in the United States might be difficult, Dr. Warrington noted, as it can be challenging logistically to get imaging done within 3 days of starting steroids. However, Dr. Moreel said it is possible to delay the start of glucocorticoids until the PET scan is performed in patients without visual symptoms or jaw claudication.

PET scans are also expensive, and it can be difficult to get insurance coverage in the United States. However, other imaging modalities could potentially be used in similar ways, Dr. Warrington said. “One could potentially extrapolate to say that if there is difficulty with accessing PET scan, we could use other modalities like CT or MRI basically to see whether the aorta is inflamed or not.”

Dr. Moreel disclosed no relevant financial relationships. Dr. Warrington has received compensation for consulting activities with Sanofi. Eli Lilly, Kiniksa, and Bristol-Myers Squibb have provided support to the Mayo Clinic for clinical trials related to GCA, of which Dr. Warrington served as subinvestigator.

A version of this article appeared on Medscape.com.

PET scans may serve as both a diagnostic and prognostic tool in giant cell arteritis (GCA), according to a new study.

In over 100 patients with GCA who underwent 18F-fluorodeoxyglucose PET imaging, those with elevated FDG uptake at diagnosis were more likely to develop thoracic aortic aneurysms.

“PET-CT has an excellent diagnostic accuracy for the diagnosis of GCA, certainly if both extracranial and intracranial vessels were assessed. This study shows that performing PET imaging at diagnosis in patients with GCA may also help estimate the future risk for aortic aneurysm formation,” lead author Lien Moreel, MD, of the department of internal medicine at University Hospitals Leuven (Belgium), wrote in an email. “PET imaging at diagnosis can provide both diagnostic and prognostic information in one imaging tool in patients with GCA.”

Brudersohn/CC BY-SA 3.0/Wikimedia Commons

Previous retrospective studies have found an association between FDG uptake at diagnosis and risk for aortic complications, but “prospective studies confirming these findings are lacking,” the investigators wrote. The study was published online in Annals of Internal Medicine.

In the study, Dr. Moreel and colleagues prospectively followed 106 individuals diagnosed with GCA who received FDG-PET within 3 days after starting glucocorticoids. Patients also had CT imaging at diagnosis and then CT imaging annually for up to 10 years. 

A PET scan was considered positive with an FDG uptake of grade 2 or higher in any of seven vascular regions (thoracic and abdominal aorta, subclavian, axillary, carotid, iliac, and femoral arteries). Researchers also used the results to quantify a total vascular score (TVS). Out of the entire cohort, 75 patients had a positive PET scan result.

These patients had a larger increase in the diameter of the ascending aorta and the descending aorta, as well the volume of thoracic aorta after 5 years, compared with those who had a negative PET scan result. These changes were also associated with higher TVS at diagnosis. Of the 23 patients who developed an aortic aneurysm, 18 had a positive PET scan at diagnosis.

The risk of incident thoracic aortic aneurysms was calculated to be 10 times higher in patients with positive PET scans. Fourteen of the 15 patients (93%) with an incident thoracic aortic aneurysm had positive PET results.

Up to now, “we’ve had no way of predicting which patients might be at risk of this potentially serious complication,” Kenneth Warrington, MD, chair of the department of rheumatology and director of the Vasculitis Clinic at the Mayo Clinic in Rochester, Minn., said in an interview. He was not involved with the research.

He hopes that the findings will help inform clinicians on how patients with GCA should be evaluated and monitored. Although the American College of Rheumatology conditionally recommends noninvasive imaging in patients newly diagnosed with GCA, guidance for follow-up on these patients is less clear.

“There are no clear guidelines, but most clinicians who take care of patients with GCA do obtain imaging periodically,” he said. “There is a lot of variability in the practice in terms of which type of scan is used and how often it’s done.”

Although this study did not specifically look at the benefit of screening patients, “we think that follow-up of aortic dimensions seems to be warranted in GCA patients with a positive PET scan result, especially in those with high intensity and broad extent of vascular inflammation,” Dr. Moreel said. “However, the added value of screening and the interval required should be addressed in future studies.”

Applying this study’s protocol in practice in the United States might be difficult, Dr. Warrington noted, as it can be challenging logistically to get imaging done within 3 days of starting steroids. However, Dr. Moreel said it is possible to delay the start of glucocorticoids until the PET scan is performed in patients without visual symptoms or jaw claudication.

PET scans are also expensive, and it can be difficult to get insurance coverage in the United States. However, other imaging modalities could potentially be used in similar ways, Dr. Warrington said. “One could potentially extrapolate to say that if there is difficulty with accessing PET scan, we could use other modalities like CT or MRI basically to see whether the aorta is inflamed or not.”

Dr. Moreel disclosed no relevant financial relationships. Dr. Warrington has received compensation for consulting activities with Sanofi. Eli Lilly, Kiniksa, and Bristol-Myers Squibb have provided support to the Mayo Clinic for clinical trials related to GCA, of which Dr. Warrington served as subinvestigator.

A version of this article appeared on Medscape.com.

TOPLINE:

Ultrasonography may serve as an alternative to radiography for diagnosing pediatric forearm fractures, thus reducing the number of children undergoing radiography at initial emergency department presentation, as well as their waiting time in ED.

METHODOLOGY:

• After the World Health Organization reported a lack of access to any diagnostic imaging in approximately two-thirds of the world population in 2010, ultrasonography has gained popularity in low- and middle-income countries.
• The initial use of ultrasonography is in accordance with the principle of maintaining radiation levels as low as reasonably achievable.
• The BUCKLED trial was conducted, including 270 pediatric patients (age, 5-15 years) who presented to the ED with isolated, acute, clinically nondeformed distal forearm fractures.
• The participants were randomly assigned to receive initial point-of-care ultrasonography (n = 135) or radiography (n = 135) in the ED.
• The primary outcome was the physical function of the affected arm at 4 weeks evaluated using the Pediatric Upper Extremity Short Patient-Reported Outcomes Measurement Information System (PROMIS) tool.

TAKEAWAY:

• At 4 weeks, mean PROMIS scores were 36.4 and 36.3 points in ultrasonography and radiography groups, respectively (mean difference, 0.1 point; 95% confidence interval, − 1.3 to 1.4), indicating noninferiority of ultrasonography over radiography.
• Ultrasonography and radiography groups showed similar efficacy in terms of PROMIS scores at 1 week (MD, 0.7 points; 95% CI, − 1.4 to 2.8) and 8 weeks (MD, 0.1 points; 95% CI, − 0.5 to 0.7).
• Participants in the ultrasonography group had a shorter length of stay in the ED (median difference, 15 minutes; 95% CI, 1-29) and a shorter treatment time (median difference, 28 minutes; 95% CI, 17-40) than those in the radiography group.
• No important fractures were missed with ultrasonography, and no significant difference was observed in the frequency of adverse events or unplanned returns to the ED between the two groups.

IN PRACTICE:

Noting the benefit-risk profile of an ultrasound-first approach in an ED setting, the lead author, Peter J. Snelling, MB, BS, MPH&TM, from Menzies Health Institute Queensland, Gold Coast, Australia, said: “It is highly unlikely that any important fractures would be missed using the protocol that we trained clinicians. The risk is low and the benefit is moderate, such as reducing length of stay and increased level of patient satisfaction.”

He further added that, “with an ultrasound-first approach, clinicians can scan the patient at time of review and may even be able to discharge them immediately (two-thirds of instances in our NEJM trial). This places the patient at the center of care being provided.”
 

SOURCE: 

Authors from the BUCKLED Trial Group published their study in the New England Journal of Medicine.

LIMITATIONS:

PROMIS scores may have been affected by variations in subsequent therapeutic interventions rather than the initial diagnostic method. PROMIS tool was not validated in children younger than 5 years of age.

DISCLOSURES:

The study was funded by the Emergency Medicine Foundation and others. The authors have declared no relevant interests to disclose.

A version of this article first appeared on Medscape.com.

TOPLINE:

Ultrasonography may serve as an alternative to radiography for diagnosing pediatric forearm fractures, thus reducing the number of children undergoing radiography at initial emergency department presentation, as well as their waiting time in ED.

METHODOLOGY:

• After the World Health Organization reported a lack of access to any diagnostic imaging in approximately two-thirds of the world population in 2010, ultrasonography has gained popularity in low- and middle-income countries.
• The initial use of ultrasonography is in accordance with the principle of maintaining radiation levels as low as reasonably achievable.
• The BUCKLED trial was conducted, including 270 pediatric patients (age, 5-15 years) who presented to the ED with isolated, acute, clinically nondeformed distal forearm fractures.
• The participants were randomly assigned to receive initial point-of-care ultrasonography (n = 135) or radiography (n = 135) in the ED.
• The primary outcome was the physical function of the affected arm at 4 weeks evaluated using the Pediatric Upper Extremity Short Patient-Reported Outcomes Measurement Information System (PROMIS) tool.

TAKEAWAY:

• At 4 weeks, mean PROMIS scores were 36.4 and 36.3 points in ultrasonography and radiography groups, respectively (mean difference, 0.1 point; 95% confidence interval, − 1.3 to 1.4), indicating noninferiority of ultrasonography over radiography.
• Ultrasonography and radiography groups showed similar efficacy in terms of PROMIS scores at 1 week (MD, 0.7 points; 95% CI, − 1.4 to 2.8) and 8 weeks (MD, 0.1 points; 95% CI, − 0.5 to 0.7).
• Participants in the ultrasonography group had a shorter length of stay in the ED (median difference, 15 minutes; 95% CI, 1-29) and a shorter treatment time (median difference, 28 minutes; 95% CI, 17-40) than those in the radiography group.
• No important fractures were missed with ultrasonography, and no significant difference was observed in the frequency of adverse events or unplanned returns to the ED between the two groups.

IN PRACTICE:

Noting the benefit-risk profile of an ultrasound-first approach in an ED setting, the lead author, Peter J. Snelling, MB, BS, MPH&TM, from Menzies Health Institute Queensland, Gold Coast, Australia, said: “It is highly unlikely that any important fractures would be missed using the protocol that we trained clinicians. The risk is low and the benefit is moderate, such as reducing length of stay and increased level of patient satisfaction.”

He further added that, “with an ultrasound-first approach, clinicians can scan the patient at time of review and may even be able to discharge them immediately (two-thirds of instances in our NEJM trial). This places the patient at the center of care being provided.”
 

SOURCE: 

Authors from the BUCKLED Trial Group published their study in the New England Journal of Medicine.

LIMITATIONS:

PROMIS scores may have been affected by variations in subsequent therapeutic interventions rather than the initial diagnostic method. PROMIS tool was not validated in children younger than 5 years of age.

DISCLOSURES:

The study was funded by the Emergency Medicine Foundation and others. The authors have declared no relevant interests to disclose.

A version of this article first appeared on Medscape.com.

TOPLINE:

Ultrasonography may serve as an alternative to radiography for diagnosing pediatric forearm fractures, thus reducing the number of children undergoing radiography at initial emergency department presentation, as well as their waiting time in ED.

METHODOLOGY:

• After the World Health Organization reported a lack of access to any diagnostic imaging in approximately two-thirds of the world population in 2010, ultrasonography has gained popularity in low- and middle-income countries.
• The initial use of ultrasonography is in accordance with the principle of maintaining radiation levels as low as reasonably achievable.
• The BUCKLED trial was conducted, including 270 pediatric patients (age, 5-15 years) who presented to the ED with isolated, acute, clinically nondeformed distal forearm fractures.
• The participants were randomly assigned to receive initial point-of-care ultrasonography (n = 135) or radiography (n = 135) in the ED.
• The primary outcome was the physical function of the affected arm at 4 weeks evaluated using the Pediatric Upper Extremity Short Patient-Reported Outcomes Measurement Information System (PROMIS) tool.

TAKEAWAY:

• At 4 weeks, mean PROMIS scores were 36.4 and 36.3 points in ultrasonography and radiography groups, respectively (mean difference, 0.1 point; 95% confidence interval, − 1.3 to 1.4), indicating noninferiority of ultrasonography over radiography.
• Ultrasonography and radiography groups showed similar efficacy in terms of PROMIS scores at 1 week (MD, 0.7 points; 95% CI, − 1.4 to 2.8) and 8 weeks (MD, 0.1 points; 95% CI, − 0.5 to 0.7).
• Participants in the ultrasonography group had a shorter length of stay in the ED (median difference, 15 minutes; 95% CI, 1-29) and a shorter treatment time (median difference, 28 minutes; 95% CI, 17-40) than those in the radiography group.
• No important fractures were missed with ultrasonography, and no significant difference was observed in the frequency of adverse events or unplanned returns to the ED between the two groups.

IN PRACTICE:

Noting the benefit-risk profile of an ultrasound-first approach in an ED setting, the lead author, Peter J. Snelling, MB, BS, MPH&TM, from Menzies Health Institute Queensland, Gold Coast, Australia, said: “It is highly unlikely that any important fractures would be missed using the protocol that we trained clinicians. The risk is low and the benefit is moderate, such as reducing length of stay and increased level of patient satisfaction.”

He further added that, “with an ultrasound-first approach, clinicians can scan the patient at time of review and may even be able to discharge them immediately (two-thirds of instances in our NEJM trial). This places the patient at the center of care being provided.”
 

SOURCE: 

Authors from the BUCKLED Trial Group published their study in the New England Journal of Medicine.

LIMITATIONS:

PROMIS scores may have been affected by variations in subsequent therapeutic interventions rather than the initial diagnostic method. PROMIS tool was not validated in children younger than 5 years of age.

DISCLOSURES:

The study was funded by the Emergency Medicine Foundation and others. The authors have declared no relevant interests to disclose.

A version of this article first appeared on Medscape.com.

A routine role for intravascular imaging (IVI) guidance for percutaneous coronary intervention (PCI) has long been favored by many of the technology’s researchers and enthusiasts. Now evidence from large, randomized trials may be catching up with such aspirations, though not without caveats.

Recently unveiled studies collectively suggest that such IVI guidance, at least for PCI of more challenging lesions, can improve the effectiveness of coronary stent delivery in ways that directly lead to better outcomes.

One way IVI guidance may achieve that, the research suggests, albeit more speculatively, is by cutting risk for stent thrombosis, compared with the risk associated with angiography-only PCI.

The new studies, two large randomized IVI trials plus a meta-analysis of 20 such studies, were presented at the annual congress of the European Society of Cardiology.

In one, called ILUMIEN-4, PCI guided by optical coherence tomography (OCT) was associated with fewer procedural complications and better acute results – that is, larger post-PCI minimum stent area (MSA) – than in angiography-only procedures (P < .001). Poststenting MSA, an established predictor of clinical outcomes, was the primary imaging endpoint of the trial with almost 2,500 patients.

Yet the OCT group’s greater post-PCI MSA did not translate to reduced risk for the primary clinical endpoint of 2-year target-vessel failure. Among secondary endpoints, however, stent thrombosis at some point during the follow-up was 64% less likely (P = .02) with OCT guidance than angiography-only PCI.

ILUMIEN-4, despite its neutral clinical result, still “strongly advocates” for PCI guidance by OCT, at least among patients like those in the trial, said principal investigator Ziad Ali, MD, DPhil. He based that largely on the strategy’s greater postprocedure lumen areas in the trials, which are among “the strongest independent predictors for long term outcomes,” said Dr. Ali, of St. Francis Hospital & Heart Center, Roslyn, N.Y., at a press conference on IVI trials during the ESC Congress.
 

Selected complex lesion type

In contrast, the OCTOBER trial, presented at the sessions back to back with ILUMIEN-4, saw OCT guidance lead to better clinical outcomes than angiography alone after PCI of bifurcation lesions, which normally can be a special challenge for operators.

In the trial, which entered about 1,200 patients with such complex lesions, the 2-year risk for major adverse cardiac events (MACE) fell 60% after OCT-guided PCI, compared with angiography-only procedures (P = .035).

The finding is novel for showing that OCT guidance in bifurcation PCI can make a significant clinical difference, said OCTOBER investigator Niels R. Holm, MD, at the same media presentation on IVI trials.

“Multiple studies have shown that OCT allows for optimization of bifurcation PCI, and our results confirm that such optimization may improve the patient’s prognosis,” said Dr. Holm of Aarhus (Denmark) University Hospital.

ILUMIEN-4 and OCTOBER, both of which prespecified the Xience (Abbott) everolimus-eluting stent for the procedures, were published in the New England Journal of Medicine in tandem with their respective presentations at the ESC sessions.
 

Covering the spectrum

A meta-analysis presented at the same ESC session compared IVI using either OCT or intravascular ultrasound (IVUS) with angiography-only PCI across 20 randomized trials with a total of more than 12,000 patients.

Significant outcomes for IVI guidance versus angiography alone included a 31% drop in risk for target-lesion failure, the primary endpoint. And this study, as well, showed a steep 52% reduction in risk for in-stent thrombosis with the IVI-guided approach.

And “for the first time” in IVI studies, “we demonstrated reductions in all-myocardial-infarction and all-cause death, the latter by 25%,” Gregg Stone, MD, Icahn School of Medicine at Mount Sinai, New York, said in presenting the meta-analysis. Dr. Stone is also the ILUMIEN-4 study chairperson.

“The routine use of OCT or IVUS to guide most PCI procedures will substantially improve patient event-free survival,” he predicted, “enhancing both the long-term safety and effectiveness of the procedure.”

Dr. Stone said that IVI guidance “should be standard of care, if not in all patients, then in most patients.” Part of the rationale: PCI is unlikely to be improved much further by incremental gains in drug-eluting stent design. “That technology has almost plateaued.” But there’s yet room for “substantially improved outcomes” from adjunctive treatments and techniques such as IVI guidance.

The 20 studies in the meta-analysis encompassed an array of patients and lesions both complex and noncomplex, Dr. Stone observed, including bifurcation lesions, chronic total occlusions, left-main coronary stenoses, and MI culprit lesions.

“They really covered the spectrum of PCI,” he said. “I’m not recommending that intravascular imaging be used in every single case. But I do think it should be used in the majority of patients” and be standard of care for PCI in left-main lesions and “complex coronary disease, high-risk patients, and high-risk lesions.”
 

Unique advantage

The IVI-guidance groups in both ILUMIEN-4 and the meta-analysis showed a significant drop in risk for stent thrombosis – that is, abrupt thrombotic vessel closure, which typically occurs in 1% or fewer PCI cases but can trigger an MI and pose a mortality risk up to 45%.

Those risk reductions are consistent with a unique IVI advantage: the ability to guide optimization of stent deployments. When formally presenting ILUMIEN-4 at the ESC sessions, Ali observed that IVUS and OCT imaging allows operators to identify and often correct less-than-ideal results of an initial stent delivery – such as residual gaps between stent struts and vessel wall – that may encroach on the lumen, with possible clinical consequences.

Such imaging, said Dr. Ali, “lets you identify tissue protrusions, malappositions, dissections, and untreated reference-segment disease” that may potentially trigger thrombosis. That makes a strong argument for giving IVI guidance a more common, perhaps even routine role in PCI procedures.
 

Selling routine IVI-guided PCI in practice

“I think the study results are quite clear,” said Deepak L. Bhatt, MD, MPH, as session comoderator following the OCTOBER presentation. “The challenge, though, will be convincing the average interventional cardiologist worldwide that it was specifically the imaging and not the extra care that the patient getting OCT also inherently receives.”

Did OCT’s better trial outcomes stem from IVI itself or from greater operator attentiveness to procedural results – such as, for example, more high-pressure expansions to optimize stent placement, “the sort of thing that tends to occur when invasive imaging is added on to just plain old angiography?” Dr. Bhatt asked of Lene N. Andreasen, MD, who had just presented the OCTOBER trial. “There’s no way of uncoupling the two things.”

What can be said, “at this point, to convince interventional cardiologists that the extra time, energy, expense, is truly indicated,” that the data are “sufficient to change global practice?” asked Dr. Bhatt, Mount Sinai Hospital and Icahn School of Medicine at Mount Sinai.

That remains an open question,” acknowledged Dr. Andreasen of Aarhus University Hospital. The best argument in favor of selective IVI-guided PCI is that “we actually see a clinical benefit” in the trials. “But of course, it comes with a cost. It comes with longer procedures and more contrast.” How clinical practice responds to the new data remains to be seen, she proposed.
 

ILUMIEN-4 and OCTOBER in detail

Conducted at 80 centers in 18 countries, ILUMIEN-4 randomly assigned patients with diabetes or complex coronary lesions to undergo PCI guided by OCT or using standard angiography only, 1,233 and 1,254 patients, respectively.

Post-PCI MSA averaged 5.72 mm² with OCT guidance and 5.36 mm² in the angiography-only group (P < .001).

Their rates of target-vessel failure at 2 years were not significantly different at 7.4% and 8.2%, respectively. The 2-year composite endpoint included cardiac death, target vessel–related MI, or ischemia-driven target-vessel revascularization.

Definite or probable stent thrombosis was observed over 2 years in 0.5% of the OCT group and 1.4% of those with angiography-only PCI (hazard ratio, 0.36; 95% confidence interval, 0.14-0.91; P = .02) favoring OCT.

The OCTOBER trial, conducted at 38 centers in Europe, entered 1201 patients with stable angina or acute coronary syndromes and angiographically identified complex bifurcation lesions. They involved the left-main coronary artery in about one-fifth of cases.

Patients were randomly assigned to bifurcation PCI guided by OCT or under standard angiography, 600 and 601 patients, respectively. Rates for procedure-related complications were similar at 6.8% and 5.7%, respectively.

Over a median of 2 years, 10.1% of the OCT group and 14.1% of angiography-only patients developed a MACE event, including cardiac death, target-lesion MI, or ischemia-driven target-lesion revascularization. The adjusted HR was 0.71 (95% CI, 0.51-0.98; P = .035) in favor of OCT.
 

Meta-analysis, trials to date

The meta-analysis presented by Dr. Stone included ILUMIEN-4, OCTOBER, and 18 earlier outcomes trials comparing PCI guided by IVI, either OCT or IVUS, and angiography-only PCI. It covered 12,428 patients with chronic or acute coronary disease and followed them a mean of 26 months; the longest follow-up was 5 years. They were assigned to IVI-guided or angiography-only PCI, 7,038 and 5,390 patients, respectively.

Dr. Stone and colleagues conducted a network meta-analysis of the 20 studies, that is, a combined analysis that allowed both direct and indirect comparisons of standard angiography-only procedures to each of the other studied comparator interventions including OCT, IVUS, and either OCT or IVUS. They then derived network-estimate odds ratios for IVI-guided PCI vs angiography-only procedures.

“Hopefully, this will impact the guidelines,” Dr. Stone said of the meta-analysis. Procedures guided by IVI might become more common in clinical practice if they were to garner a Class-I guideline recommendation, the strongest recommendation category.

“That would make a difference, but we’d also need to work to remove impediments to increasing intravascular imaging guidance” for most patients undergoing PCI, he said, referring to challenges in obtaining reimbursement for IVI-guided PCI and training enough operators to handle the projected demand.

ILUMIEN-4 was funded by Abbott. OCTOBER was supported by grants from Abbott Vascular, St. Jude Medical, and Aarhus University. The network meta-analysis received statistical support from Abbott. Dr. Ali disclosed institutional grant support from Abbott, Abiomed, Acist Medical, Boston Scientific, Cardiovascular Systems, Medtronic, the National Institutes of Health, Opsens Medical, Philips, and Teleflex; consulting fees from Astra Zeneca, Philips, Shockwave; and holding equity in Elucid, Spectrawave, Shockwave, and VitalConnect. Dr. Holm and Dr. Bhatt reported numerous conflicts of interest. Dr. Andreasen disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

A routine role for intravascular imaging (IVI) guidance for percutaneous coronary intervention (PCI) has long been favored by many of the technology’s researchers and enthusiasts. Now evidence from large, randomized trials may be catching up with such aspirations, though not without caveats.

Recently unveiled studies collectively suggest that such IVI guidance, at least for PCI of more challenging lesions, can improve the effectiveness of coronary stent delivery in ways that directly lead to better outcomes.

One way IVI guidance may achieve that, the research suggests, albeit more speculatively, is by cutting risk for stent thrombosis, compared with the risk associated with angiography-only PCI.

The new studies, two large randomized IVI trials plus a meta-analysis of 20 such studies, were presented at the annual congress of the European Society of Cardiology.

In one, called ILUMIEN-4, PCI guided by optical coherence tomography (OCT) was associated with fewer procedural complications and better acute results – that is, larger post-PCI minimum stent area (MSA) – than in angiography-only procedures (P < .001). Poststenting MSA, an established predictor of clinical outcomes, was the primary imaging endpoint of the trial with almost 2,500 patients.

Yet the OCT group’s greater post-PCI MSA did not translate to reduced risk for the primary clinical endpoint of 2-year target-vessel failure. Among secondary endpoints, however, stent thrombosis at some point during the follow-up was 64% less likely (P = .02) with OCT guidance than angiography-only PCI.

ILUMIEN-4, despite its neutral clinical result, still “strongly advocates” for PCI guidance by OCT, at least among patients like those in the trial, said principal investigator Ziad Ali, MD, DPhil. He based that largely on the strategy’s greater postprocedure lumen areas in the trials, which are among “the strongest independent predictors for long term outcomes,” said Dr. Ali, of St. Francis Hospital & Heart Center, Roslyn, N.Y., at a press conference on IVI trials during the ESC Congress.
 

Selected complex lesion type

In contrast, the OCTOBER trial, presented at the sessions back to back with ILUMIEN-4, saw OCT guidance lead to better clinical outcomes than angiography alone after PCI of bifurcation lesions, which normally can be a special challenge for operators.

In the trial, which entered about 1,200 patients with such complex lesions, the 2-year risk for major adverse cardiac events (MACE) fell 60% after OCT-guided PCI, compared with angiography-only procedures (P = .035).

The finding is novel for showing that OCT guidance in bifurcation PCI can make a significant clinical difference, said OCTOBER investigator Niels R. Holm, MD, at the same media presentation on IVI trials.

“Multiple studies have shown that OCT allows for optimization of bifurcation PCI, and our results confirm that such optimization may improve the patient’s prognosis,” said Dr. Holm of Aarhus (Denmark) University Hospital.

ILUMIEN-4 and OCTOBER, both of which prespecified the Xience (Abbott) everolimus-eluting stent for the procedures, were published in the New England Journal of Medicine in tandem with their respective presentations at the ESC sessions.
 

Covering the spectrum

A meta-analysis presented at the same ESC session compared IVI using either OCT or intravascular ultrasound (IVUS) with angiography-only PCI across 20 randomized trials with a total of more than 12,000 patients.

Significant outcomes for IVI guidance versus angiography alone included a 31% drop in risk for target-lesion failure, the primary endpoint. And this study, as well, showed a steep 52% reduction in risk for in-stent thrombosis with the IVI-guided approach.

And “for the first time” in IVI studies, “we demonstrated reductions in all-myocardial-infarction and all-cause death, the latter by 25%,” Gregg Stone, MD, Icahn School of Medicine at Mount Sinai, New York, said in presenting the meta-analysis. Dr. Stone is also the ILUMIEN-4 study chairperson.

“The routine use of OCT or IVUS to guide most PCI procedures will substantially improve patient event-free survival,” he predicted, “enhancing both the long-term safety and effectiveness of the procedure.”

Dr. Stone said that IVI guidance “should be standard of care, if not in all patients, then in most patients.” Part of the rationale: PCI is unlikely to be improved much further by incremental gains in drug-eluting stent design. “That technology has almost plateaued.” But there’s yet room for “substantially improved outcomes” from adjunctive treatments and techniques such as IVI guidance.

The 20 studies in the meta-analysis encompassed an array of patients and lesions both complex and noncomplex, Dr. Stone observed, including bifurcation lesions, chronic total occlusions, left-main coronary stenoses, and MI culprit lesions.

“They really covered the spectrum of PCI,” he said. “I’m not recommending that intravascular imaging be used in every single case. But I do think it should be used in the majority of patients” and be standard of care for PCI in left-main lesions and “complex coronary disease, high-risk patients, and high-risk lesions.”
 

Unique advantage

The IVI-guidance groups in both ILUMIEN-4 and the meta-analysis showed a significant drop in risk for stent thrombosis – that is, abrupt thrombotic vessel closure, which typically occurs in 1% or fewer PCI cases but can trigger an MI and pose a mortality risk up to 45%.

Those risk reductions are consistent with a unique IVI advantage: the ability to guide optimization of stent deployments. When formally presenting ILUMIEN-4 at the ESC sessions, Ali observed that IVUS and OCT imaging allows operators to identify and often correct less-than-ideal results of an initial stent delivery – such as residual gaps between stent struts and vessel wall – that may encroach on the lumen, with possible clinical consequences.

Such imaging, said Dr. Ali, “lets you identify tissue protrusions, malappositions, dissections, and untreated reference-segment disease” that may potentially trigger thrombosis. That makes a strong argument for giving IVI guidance a more common, perhaps even routine role in PCI procedures.
 

Selling routine IVI-guided PCI in practice

“I think the study results are quite clear,” said Deepak L. Bhatt, MD, MPH, as session comoderator following the OCTOBER presentation. “The challenge, though, will be convincing the average interventional cardiologist worldwide that it was specifically the imaging and not the extra care that the patient getting OCT also inherently receives.”

Did OCT’s better trial outcomes stem from IVI itself or from greater operator attentiveness to procedural results – such as, for example, more high-pressure expansions to optimize stent placement, “the sort of thing that tends to occur when invasive imaging is added on to just plain old angiography?” Dr. Bhatt asked of Lene N. Andreasen, MD, who had just presented the OCTOBER trial. “There’s no way of uncoupling the two things.”

What can be said, “at this point, to convince interventional cardiologists that the extra time, energy, expense, is truly indicated,” that the data are “sufficient to change global practice?” asked Dr. Bhatt, Mount Sinai Hospital and Icahn School of Medicine at Mount Sinai.

That remains an open question,” acknowledged Dr. Andreasen of Aarhus University Hospital. The best argument in favor of selective IVI-guided PCI is that “we actually see a clinical benefit” in the trials. “But of course, it comes with a cost. It comes with longer procedures and more contrast.” How clinical practice responds to the new data remains to be seen, she proposed.
 

ILUMIEN-4 and OCTOBER in detail

Conducted at 80 centers in 18 countries, ILUMIEN-4 randomly assigned patients with diabetes or complex coronary lesions to undergo PCI guided by OCT or using standard angiography only, 1,233 and 1,254 patients, respectively.

Post-PCI MSA averaged 5.72 mm² with OCT guidance and 5.36 mm² in the angiography-only group (P < .001).

Their rates of target-vessel failure at 2 years were not significantly different at 7.4% and 8.2%, respectively. The 2-year composite endpoint included cardiac death, target vessel–related MI, or ischemia-driven target-vessel revascularization.

Definite or probable stent thrombosis was observed over 2 years in 0.5% of the OCT group and 1.4% of those with angiography-only PCI (hazard ratio, 0.36; 95% confidence interval, 0.14-0.91; P = .02) favoring OCT.

The OCTOBER trial, conducted at 38 centers in Europe, entered 1201 patients with stable angina or acute coronary syndromes and angiographically identified complex bifurcation lesions. They involved the left-main coronary artery in about one-fifth of cases.

Patients were randomly assigned to bifurcation PCI guided by OCT or under standard angiography, 600 and 601 patients, respectively. Rates for procedure-related complications were similar at 6.8% and 5.7%, respectively.

Over a median of 2 years, 10.1% of the OCT group and 14.1% of angiography-only patients developed a MACE event, including cardiac death, target-lesion MI, or ischemia-driven target-lesion revascularization. The adjusted HR was 0.71 (95% CI, 0.51-0.98; P = .035) in favor of OCT.
 

Meta-analysis, trials to date

The meta-analysis presented by Dr. Stone included ILUMIEN-4, OCTOBER, and 18 earlier outcomes trials comparing PCI guided by IVI, either OCT or IVUS, and angiography-only PCI. It covered 12,428 patients with chronic or acute coronary disease and followed them a mean of 26 months; the longest follow-up was 5 years. They were assigned to IVI-guided or angiography-only PCI, 7,038 and 5,390 patients, respectively.

Dr. Stone and colleagues conducted a network meta-analysis of the 20 studies, that is, a combined analysis that allowed both direct and indirect comparisons of standard angiography-only procedures to each of the other studied comparator interventions including OCT, IVUS, and either OCT or IVUS. They then derived network-estimate odds ratios for IVI-guided PCI vs angiography-only procedures.

“Hopefully, this will impact the guidelines,” Dr. Stone said of the meta-analysis. Procedures guided by IVI might become more common in clinical practice if they were to garner a Class-I guideline recommendation, the strongest recommendation category.

“That would make a difference, but we’d also need to work to remove impediments to increasing intravascular imaging guidance” for most patients undergoing PCI, he said, referring to challenges in obtaining reimbursement for IVI-guided PCI and training enough operators to handle the projected demand.

ILUMIEN-4 was funded by Abbott. OCTOBER was supported by grants from Abbott Vascular, St. Jude Medical, and Aarhus University. The network meta-analysis received statistical support from Abbott. Dr. Ali disclosed institutional grant support from Abbott, Abiomed, Acist Medical, Boston Scientific, Cardiovascular Systems, Medtronic, the National Institutes of Health, Opsens Medical, Philips, and Teleflex; consulting fees from Astra Zeneca, Philips, Shockwave; and holding equity in Elucid, Spectrawave, Shockwave, and VitalConnect. Dr. Holm and Dr. Bhatt reported numerous conflicts of interest. Dr. Andreasen disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

A routine role for intravascular imaging (IVI) guidance for percutaneous coronary intervention (PCI) has long been favored by many of the technology’s researchers and enthusiasts. Now evidence from large, randomized trials may be catching up with such aspirations, though not without caveats.

Recently unveiled studies collectively suggest that such IVI guidance, at least for PCI of more challenging lesions, can improve the effectiveness of coronary stent delivery in ways that directly lead to better outcomes.

One way IVI guidance may achieve that, the research suggests, albeit more speculatively, is by cutting risk for stent thrombosis, compared with the risk associated with angiography-only PCI.

The new studies, two large randomized IVI trials plus a meta-analysis of 20 such studies, were presented at the annual congress of the European Society of Cardiology.

In one, called ILUMIEN-4, PCI guided by optical coherence tomography (OCT) was associated with fewer procedural complications and better acute results – that is, larger post-PCI minimum stent area (MSA) – than in angiography-only procedures (P < .001). Poststenting MSA, an established predictor of clinical outcomes, was the primary imaging endpoint of the trial with almost 2,500 patients.

Yet the OCT group’s greater post-PCI MSA did not translate to reduced risk for the primary clinical endpoint of 2-year target-vessel failure. Among secondary endpoints, however, stent thrombosis at some point during the follow-up was 64% less likely (P = .02) with OCT guidance than angiography-only PCI.

ILUMIEN-4, despite its neutral clinical result, still “strongly advocates” for PCI guidance by OCT, at least among patients like those in the trial, said principal investigator Ziad Ali, MD, DPhil. He based that largely on the strategy’s greater postprocedure lumen areas in the trials, which are among “the strongest independent predictors for long term outcomes,” said Dr. Ali, of St. Francis Hospital & Heart Center, Roslyn, N.Y., at a press conference on IVI trials during the ESC Congress.
 

Selected complex lesion type

In contrast, the OCTOBER trial, presented at the sessions back to back with ILUMIEN-4, saw OCT guidance lead to better clinical outcomes than angiography alone after PCI of bifurcation lesions, which normally can be a special challenge for operators.

In the trial, which entered about 1,200 patients with such complex lesions, the 2-year risk for major adverse cardiac events (MACE) fell 60% after OCT-guided PCI, compared with angiography-only procedures (P = .035).

The finding is novel for showing that OCT guidance in bifurcation PCI can make a significant clinical difference, said OCTOBER investigator Niels R. Holm, MD, at the same media presentation on IVI trials.

“Multiple studies have shown that OCT allows for optimization of bifurcation PCI, and our results confirm that such optimization may improve the patient’s prognosis,” said Dr. Holm of Aarhus (Denmark) University Hospital.

ILUMIEN-4 and OCTOBER, both of which prespecified the Xience (Abbott) everolimus-eluting stent for the procedures, were published in the New England Journal of Medicine in tandem with their respective presentations at the ESC sessions.
 

Covering the spectrum

A meta-analysis presented at the same ESC session compared IVI using either OCT or intravascular ultrasound (IVUS) with angiography-only PCI across 20 randomized trials with a total of more than 12,000 patients.

Significant outcomes for IVI guidance versus angiography alone included a 31% drop in risk for target-lesion failure, the primary endpoint. And this study, as well, showed a steep 52% reduction in risk for in-stent thrombosis with the IVI-guided approach.

And “for the first time” in IVI studies, “we demonstrated reductions in all-myocardial-infarction and all-cause death, the latter by 25%,” Gregg Stone, MD, Icahn School of Medicine at Mount Sinai, New York, said in presenting the meta-analysis. Dr. Stone is also the ILUMIEN-4 study chairperson.

“The routine use of OCT or IVUS to guide most PCI procedures will substantially improve patient event-free survival,” he predicted, “enhancing both the long-term safety and effectiveness of the procedure.”

Dr. Stone said that IVI guidance “should be standard of care, if not in all patients, then in most patients.” Part of the rationale: PCI is unlikely to be improved much further by incremental gains in drug-eluting stent design. “That technology has almost plateaued.” But there’s yet room for “substantially improved outcomes” from adjunctive treatments and techniques such as IVI guidance.

The 20 studies in the meta-analysis encompassed an array of patients and lesions both complex and noncomplex, Dr. Stone observed, including bifurcation lesions, chronic total occlusions, left-main coronary stenoses, and MI culprit lesions.

“They really covered the spectrum of PCI,” he said. “I’m not recommending that intravascular imaging be used in every single case. But I do think it should be used in the majority of patients” and be standard of care for PCI in left-main lesions and “complex coronary disease, high-risk patients, and high-risk lesions.”
 

Unique advantage

The IVI-guidance groups in both ILUMIEN-4 and the meta-analysis showed a significant drop in risk for stent thrombosis – that is, abrupt thrombotic vessel closure, which typically occurs in 1% or fewer PCI cases but can trigger an MI and pose a mortality risk up to 45%.

Those risk reductions are consistent with a unique IVI advantage: the ability to guide optimization of stent deployments. When formally presenting ILUMIEN-4 at the ESC sessions, Ali observed that IVUS and OCT imaging allows operators to identify and often correct less-than-ideal results of an initial stent delivery – such as residual gaps between stent struts and vessel wall – that may encroach on the lumen, with possible clinical consequences.

Such imaging, said Dr. Ali, “lets you identify tissue protrusions, malappositions, dissections, and untreated reference-segment disease” that may potentially trigger thrombosis. That makes a strong argument for giving IVI guidance a more common, perhaps even routine role in PCI procedures.
 

Selling routine IVI-guided PCI in practice

“I think the study results are quite clear,” said Deepak L. Bhatt, MD, MPH, as session comoderator following the OCTOBER presentation. “The challenge, though, will be convincing the average interventional cardiologist worldwide that it was specifically the imaging and not the extra care that the patient getting OCT also inherently receives.”

Did OCT’s better trial outcomes stem from IVI itself or from greater operator attentiveness to procedural results – such as, for example, more high-pressure expansions to optimize stent placement, “the sort of thing that tends to occur when invasive imaging is added on to just plain old angiography?” Dr. Bhatt asked of Lene N. Andreasen, MD, who had just presented the OCTOBER trial. “There’s no way of uncoupling the two things.”

What can be said, “at this point, to convince interventional cardiologists that the extra time, energy, expense, is truly indicated,” that the data are “sufficient to change global practice?” asked Dr. Bhatt, Mount Sinai Hospital and Icahn School of Medicine at Mount Sinai.

That remains an open question,” acknowledged Dr. Andreasen of Aarhus University Hospital. The best argument in favor of selective IVI-guided PCI is that “we actually see a clinical benefit” in the trials. “But of course, it comes with a cost. It comes with longer procedures and more contrast.” How clinical practice responds to the new data remains to be seen, she proposed.
 

ILUMIEN-4 and OCTOBER in detail

Conducted at 80 centers in 18 countries, ILUMIEN-4 randomly assigned patients with diabetes or complex coronary lesions to undergo PCI guided by OCT or using standard angiography only, 1,233 and 1,254 patients, respectively.

Post-PCI MSA averaged 5.72 mm² with OCT guidance and 5.36 mm² in the angiography-only group (P < .001).

Their rates of target-vessel failure at 2 years were not significantly different at 7.4% and 8.2%, respectively. The 2-year composite endpoint included cardiac death, target vessel–related MI, or ischemia-driven target-vessel revascularization.

Definite or probable stent thrombosis was observed over 2 years in 0.5% of the OCT group and 1.4% of those with angiography-only PCI (hazard ratio, 0.36; 95% confidence interval, 0.14-0.91; P = .02) favoring OCT.

The OCTOBER trial, conducted at 38 centers in Europe, entered 1201 patients with stable angina or acute coronary syndromes and angiographically identified complex bifurcation lesions. They involved the left-main coronary artery in about one-fifth of cases.

Patients were randomly assigned to bifurcation PCI guided by OCT or under standard angiography, 600 and 601 patients, respectively. Rates for procedure-related complications were similar at 6.8% and 5.7%, respectively.

Over a median of 2 years, 10.1% of the OCT group and 14.1% of angiography-only patients developed a MACE event, including cardiac death, target-lesion MI, or ischemia-driven target-lesion revascularization. The adjusted HR was 0.71 (95% CI, 0.51-0.98; P = .035) in favor of OCT.
 

Meta-analysis, trials to date

The meta-analysis presented by Dr. Stone included ILUMIEN-4, OCTOBER, and 18 earlier outcomes trials comparing PCI guided by IVI, either OCT or IVUS, and angiography-only PCI. It covered 12,428 patients with chronic or acute coronary disease and followed them a mean of 26 months; the longest follow-up was 5 years. They were assigned to IVI-guided or angiography-only PCI, 7,038 and 5,390 patients, respectively.

Dr. Stone and colleagues conducted a network meta-analysis of the 20 studies, that is, a combined analysis that allowed both direct and indirect comparisons of standard angiography-only procedures to each of the other studied comparator interventions including OCT, IVUS, and either OCT or IVUS. They then derived network-estimate odds ratios for IVI-guided PCI vs angiography-only procedures.

“Hopefully, this will impact the guidelines,” Dr. Stone said of the meta-analysis. Procedures guided by IVI might become more common in clinical practice if they were to garner a Class-I guideline recommendation, the strongest recommendation category.

“That would make a difference, but we’d also need to work to remove impediments to increasing intravascular imaging guidance” for most patients undergoing PCI, he said, referring to challenges in obtaining reimbursement for IVI-guided PCI and training enough operators to handle the projected demand.

ILUMIEN-4 was funded by Abbott. OCTOBER was supported by grants from Abbott Vascular, St. Jude Medical, and Aarhus University. The network meta-analysis received statistical support from Abbott. Dr. Ali disclosed institutional grant support from Abbott, Abiomed, Acist Medical, Boston Scientific, Cardiovascular Systems, Medtronic, the National Institutes of Health, Opsens Medical, Philips, and Teleflex; consulting fees from Astra Zeneca, Philips, Shockwave; and holding equity in Elucid, Spectrawave, Shockwave, and VitalConnect. Dr. Holm and Dr. Bhatt reported numerous conflicts of interest. Dr. Andreasen disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

AMSTERDAM – A simple, low-cost 5-day course of dietary inorganic nitrate has shown apparent overwhelming benefit in preventing contrast-induced nephropathy (CIN) and reducing subsequent renal and cardiovascular outcomes.

In the NITRATE-CIN Study, non-ST segment elevation myocardial infarction acute coronary syndrome (ACS) patients at risk of renal injury from coronary angiography who received dietary inorganic nitrates had a 70% reduction in CIN compared with those given placebo.

The nitrate group also showed an impressive reduction in periprocedural myocardial infarction (MI) and improved renal function at 3 months, as well as a halving of major adverse cardiovascular events and major adverse kidney events at 1 year.

The trial was presented by Dan Jones, MD, Barts Health NHS Trust, London, at the annual congress of the European Society of Cardiology.

“Currently, aside from intravenous hydration, there is no proven treatment that reduces contrast-induced nephropathy. We feel that dietary inorganic nitrate shows huge promise in this study, and these findings could have important implications in reducing this serious complication of coronary angiography,” Dr. Jones concluded.

He explained that the product used was a formulation of dietary inorganic nitrates given as potassium nitrate capsules, which the study investigators produced specifically for this trial.

At this point, “the only way to get inorganic nitrate is in the diet – specifically by consuming beetroot juice or green leafy vegetables such as spinach and rocket. From a clinician perspective, while these results suggest this is an effective therapy and has great potential, it is not currently possible to prescribe the medication we used in our study, although we are working on producing a commercial product,” he said in an interview.

However, Dr. Jones noted that it is possible to buy beetroot shots, which contain 7 mmol of potassium nitrate in each shot, from health food shops and websites, and two such shots per day for 5 days would give a dose similar to that used in this study, starting the day before angiography.

“While we need a larger multicenter study to confirm these results, studies so far suggest no signal at all that there is any harm in this approach, and there could be a great deal of benefit in taking a couple of beetroot shots prior to and for a few days after an angiogram,” he said.
 

Dietary nitrates “make sense”

Designated discussant of the NITRATE-CIN trial at the ESC Hotline session, Roxanna Mehran, MD, Icahn School of Medicine at Mount Sinai, New York, said the study was well designed, and the “interesting and plausible” hypothesis to raise nitric oxide levels by dietary nitrates “makes sense.”

On the main findings of a major significant 50% reduction in acute kidney injury, Dr. Mehran said, “It is difficult to imagine such a reduction is possible.”

She pointed out that the large reduction in major adverse cardiac events and major adverse kidney events at 1 year also suggests that there is a sustained benefit in protecting the kidney.

“We’re all going to get on beet juice after this,” she quipped.

Still, Dr. Mehran questioned whether the results were “too good to be true,” adding that a larger trial actually powered for longer term outcome events is needed, as well as a better understanding of whether CIN has a causative role in mortality.

Responding to questions about whether such a large effect could actually be achieved with dietary nitrates, Dr. Jones said he thought there would definitely be some benefits, but maybe not quite as large as those seen in this study.

“From our pilot data we thought nitrate may be effective in preventing CIN,” he said in an interview. “We recruited a higher risk group than we thought, which is why the control event rates were higher than we expected, but the acute kidney injury reduction is roughly what we had estimated, and makes sense biologically.”

Dr. Jones acknowledged that the large reductions in long-term major adverse cardiovascular and kidney events were unexpected.

“The trial was not powered to see reductions in these outcomes, so we need to see if those event reductions can be replicated in larger multicenter trials,” he said. “But this was a double-blind placebo-controlled trial so in this trial the effects are real, and I think the effect size in this trial is too large for there not to be a beneficial effect.

“But I’m not so sure that we would see the same magnitude of effect when we have a larger study with tighter confidence intervals but perhaps a 20%-25% reduction in cardiovascular and kidney may be more realistic, which would still be amazing for such an easy and cost-effective intervention,” Dr. Jones added.

A larger trial is now being planned.

The researchers are also working on the development of a commercial form of dietary inorganic nitrate that would be needed for larger multicenter studies and would then be generally available. “We want this to be a low-cost product that would be available to all,” Dr. Jones said.

He noted that other studies have shown that dietary inorganic nitrates in the form of beetroot juice lower blood pressure; there are suggestions it may also lower cholesterol and prevent stent restenosis, and athletes sometimes take it to increase their aerobic capacity.

“There appears to be many benefits of dietary nitrates, and the one thing we can do at this time is to encourage people to increase their dietary nitrate consumption by eating large quantities of green leafy vegetables and beetroot,” Dr. Jones said.
 

Replacing lost nitric oxide

In his presentation, Dr. Jones noted that CIN is a serious complication after coronary angiography and is associated with longer hospital stays, worse long-term kidney function, and increased risk of MI and death.

The incidence varies depending on patient risk and definitions used, but it can affect up to 50% of high-risk ACS patients – older patients and/or those with heart failure, chronic kidney disease, or diabetes.

“We don’t really understand the mechanisms that cause CIN, but multiple proposed mechanisms exist, and we know from previous studies that a deficiency of nitric oxide is crucial to the development of CIN,” he explained. “We also know that [nitric oxide] is crucial for normal renal hemostasis. Therefore, a potential therapeutic target to prevent CIN would be to replace this lost nitric oxide.”

The inorganic nitrate evaluated in this trial is found in the diet, is produced endogenously, and is different from medicinally synthesized organic nitrates such as isosorbide mononitrate, he said.

“Isosorbide mononitrate/dinitrate tablets contain organic nitrates and while they are good for angina, we know that they do not have the same beneficial effects on the sustained generation of nitric oxide as inorganic nitrates,” Dr. Jones added.
 

NITRATE-CIN study

NITRATE-CIN was a double-blind, randomized, placebo-controlled trial conducted at Queen Mary University of London and St. Bartholomew’s Hospital in London, which tested the effectiveness of inorganic nitrate in preventing contrast-induced nephropathy in 640 patients with non-ST elevation ACS referred for invasive coronary angiography.

To be eligible for the trial, patients had to be at risk of contrast-induced nephropathy with an estimated glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m² or have two of the following significant risk factors: diabetes, liver failure, over 70 years of age, exposure to contrast within 7 days, heart failure, or on concomitant renally acting drugs.

Patients were randomly assigned to a formulation of potassium nitrate (12 mmol/744 mg nitrate) per day given as capsules for a 5-day course with the first dose administered prior to angiography or to a control group that received potassium chloride with a matched potassium concentration.

The patient population had a mean age of 71 years, 73% were male, 75% were White, 46% had diabetes, and 56% had chronic kidney disease. There was a 13% loss to follow-up, which was attributed to the COVID pandemic.

The amount of contrast administration was 180 mL in the placebo and 170 mL in the nitrate arm, with 50% of patients undergoing some sort of revascularization.

The primary endpoint was the incidence of CIN as defined by KDIGO criteria – a series of stages of acute kidney injury defined by changes in serum creatinine within 72 hours and up to 1 week.

Results showed that this primary CIN endpoint was reduced significantly from 30% in the placebo arm to 9.1% in the nitrate group, a 70% relative risk reduction (P < .0001). The majority (90%) of this CIN was stage 1, but 10% was stage 2.

Consistent results were seen when an alternative definition of CIN (Mehran) was used, although the rates in both arms were lower than when the KDIGO definition was used.

The benefit was seen across prespecified subgroups including diabetes status, troponin positivity, and Mehran risk. But the benefit seemed to be attenuated in patients on preexisting organic nitrate therapy, although the numbers in these groups were too small to draw definitive conclusions.

As would be expected, there were significant elevations in both systemic nitrate and nitrite levels both up to 72 hours after the procedure, which was consistent with the 5-day course. This was associated with reductions in systolic and diastolic blood pressure, but not associated with any adverse events, Dr. Jones reported.

Rates of procedural MI, a prespecified secondary endpoint, were reduced from 12.5% to 4.1% in those on inorganic nitrates (P = .003).

Looking at longer term outcomes, kidney function was improved at 3 months as measured by change in eGFR, which showed a 10% relative improvement of 5.2 mL/min per 1.73 m² (10%) in the nitrate group vs. the placebo group. Serum creatinine levels were also significantly increased in the nitrate group.

At 12 months, there was a significant 50% relative reduction in major adverse cardiovascular events – including all-cause mortality, recurrent MI, and recurrent revascularization – which were reduced from 18.1% in the placebo group to 9.1% in the nitrate group, with a reduction in all three of the constituent components of the composite endpoint including all-cause mortality.

Major adverse kidney events (all-cause mortality, renal replacement therapy, or persistent renal dysfunction) were also reduced at 12 months from 28.4% in the placebo group to 10.7% in the nitrate group (P < .0001), a 60% relative reduction. This was driven by lower rates of all-cause mortality and persistent renal dysfunction.

While Dr. Jones said these results on major cardiovascular and kidney outcomes should be viewed as hypothesis-generating at the present time, he said there were biological mechanisms that could explain these benefits.

“We saw a reduction in procedural MI, and we know there is a lot of similar biology in preventing procedural MI and subsequent cardiac events in the acute phase. This, in combination with the large reduction in acute kidney injury, could explain why there’s improved outcomes out to 12 months.”

In her comments, Dr. Mehran congratulated the investigators on having conducted the first study to have shown benefit in the prevention of contrast-associated acute kidney injury as well as major adverse cardiovascular and kidney events associated with the condition.

She used the term “contrast-associated acute kidney injury” rather than “contrast-induced nephropathy” because, she said, it has not been proven that the acute kidney injury seen after angiography is actually caused by the contrast and “so many other things are occurring during procedures when these patients are presenting with different syndromes.”

Dr. Mehran pointed out some weaknesses in the NITRATE-CIN study including the single-center design, the large volume of contrast administered, 13% of patients missing the primary endpoint blood draw, and an imbalance in relevant baseline characteristics despite randomization.

The NITRATE-CIN study was funded by Heart Research UK. Dr. Jones has disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

AMSTERDAM – A simple, low-cost 5-day course of dietary inorganic nitrate has shown apparent overwhelming benefit in preventing contrast-induced nephropathy (CIN) and reducing subsequent renal and cardiovascular outcomes.

In the NITRATE-CIN Study, non-ST segment elevation myocardial infarction acute coronary syndrome (ACS) patients at risk of renal injury from coronary angiography who received dietary inorganic nitrates had a 70% reduction in CIN compared with those given placebo.

The nitrate group also showed an impressive reduction in periprocedural myocardial infarction (MI) and improved renal function at 3 months, as well as a halving of major adverse cardiovascular events and major adverse kidney events at 1 year.

The trial was presented by Dan Jones, MD, Barts Health NHS Trust, London, at the annual congress of the European Society of Cardiology.

“Currently, aside from intravenous hydration, there is no proven treatment that reduces contrast-induced nephropathy. We feel that dietary inorganic nitrate shows huge promise in this study, and these findings could have important implications in reducing this serious complication of coronary angiography,” Dr. Jones concluded.

He explained that the product used was a formulation of dietary inorganic nitrates given as potassium nitrate capsules, which the study investigators produced specifically for this trial.

At this point, “the only way to get inorganic nitrate is in the diet – specifically by consuming beetroot juice or green leafy vegetables such as spinach and rocket. From a clinician perspective, while these results suggest this is an effective therapy and has great potential, it is not currently possible to prescribe the medication we used in our study, although we are working on producing a commercial product,” he said in an interview.

However, Dr. Jones noted that it is possible to buy beetroot shots, which contain 7 mmol of potassium nitrate in each shot, from health food shops and websites, and two such shots per day for 5 days would give a dose similar to that used in this study, starting the day before angiography.

“While we need a larger multicenter study to confirm these results, studies so far suggest no signal at all that there is any harm in this approach, and there could be a great deal of benefit in taking a couple of beetroot shots prior to and for a few days after an angiogram,” he said.
 

Dietary nitrates “make sense”

Designated discussant of the NITRATE-CIN trial at the ESC Hotline session, Roxanna Mehran, MD, Icahn School of Medicine at Mount Sinai, New York, said the study was well designed, and the “interesting and plausible” hypothesis to raise nitric oxide levels by dietary nitrates “makes sense.”

On the main findings of a major significant 50% reduction in acute kidney injury, Dr. Mehran said, “It is difficult to imagine such a reduction is possible.”

She pointed out that the large reduction in major adverse cardiac events and major adverse kidney events at 1 year also suggests that there is a sustained benefit in protecting the kidney.

“We’re all going to get on beet juice after this,” she quipped.

Still, Dr. Mehran questioned whether the results were “too good to be true,” adding that a larger trial actually powered for longer term outcome events is needed, as well as a better understanding of whether CIN has a causative role in mortality.

Responding to questions about whether such a large effect could actually be achieved with dietary nitrates, Dr. Jones said he thought there would definitely be some benefits, but maybe not quite as large as those seen in this study.

“From our pilot data we thought nitrate may be effective in preventing CIN,” he said in an interview. “We recruited a higher risk group than we thought, which is why the control event rates were higher than we expected, but the acute kidney injury reduction is roughly what we had estimated, and makes sense biologically.”

Dr. Jones acknowledged that the large reductions in long-term major adverse cardiovascular and kidney events were unexpected.

“The trial was not powered to see reductions in these outcomes, so we need to see if those event reductions can be replicated in larger multicenter trials,” he said. “But this was a double-blind placebo-controlled trial so in this trial the effects are real, and I think the effect size in this trial is too large for there not to be a beneficial effect.

“But I’m not so sure that we would see the same magnitude of effect when we have a larger study with tighter confidence intervals but perhaps a 20%-25% reduction in cardiovascular and kidney may be more realistic, which would still be amazing for such an easy and cost-effective intervention,” Dr. Jones added.

A larger trial is now being planned.

The researchers are also working on the development of a commercial form of dietary inorganic nitrate that would be needed for larger multicenter studies and would then be generally available. “We want this to be a low-cost product that would be available to all,” Dr. Jones said.

He noted that other studies have shown that dietary inorganic nitrates in the form of beetroot juice lower blood pressure; there are suggestions it may also lower cholesterol and prevent stent restenosis, and athletes sometimes take it to increase their aerobic capacity.

“There appears to be many benefits of dietary nitrates, and the one thing we can do at this time is to encourage people to increase their dietary nitrate consumption by eating large quantities of green leafy vegetables and beetroot,” Dr. Jones said.
 

Replacing lost nitric oxide

In his presentation, Dr. Jones noted that CIN is a serious complication after coronary angiography and is associated with longer hospital stays, worse long-term kidney function, and increased risk of MI and death.

The incidence varies depending on patient risk and definitions used, but it can affect up to 50% of high-risk ACS patients – older patients and/or those with heart failure, chronic kidney disease, or diabetes.

“We don’t really understand the mechanisms that cause CIN, but multiple proposed mechanisms exist, and we know from previous studies that a deficiency of nitric oxide is crucial to the development of CIN,” he explained. “We also know that [nitric oxide] is crucial for normal renal hemostasis. Therefore, a potential therapeutic target to prevent CIN would be to replace this lost nitric oxide.”

The inorganic nitrate evaluated in this trial is found in the diet, is produced endogenously, and is different from medicinally synthesized organic nitrates such as isosorbide mononitrate, he said.

“Isosorbide mononitrate/dinitrate tablets contain organic nitrates and while they are good for angina, we know that they do not have the same beneficial effects on the sustained generation of nitric oxide as inorganic nitrates,” Dr. Jones added.
 

NITRATE-CIN study

NITRATE-CIN was a double-blind, randomized, placebo-controlled trial conducted at Queen Mary University of London and St. Bartholomew’s Hospital in London, which tested the effectiveness of inorganic nitrate in preventing contrast-induced nephropathy in 640 patients with non-ST elevation ACS referred for invasive coronary angiography.

To be eligible for the trial, patients had to be at risk of contrast-induced nephropathy with an estimated glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m² or have two of the following significant risk factors: diabetes, liver failure, over 70 years of age, exposure to contrast within 7 days, heart failure, or on concomitant renally acting drugs.

Patients were randomly assigned to a formulation of potassium nitrate (12 mmol/744 mg nitrate) per day given as capsules for a 5-day course with the first dose administered prior to angiography or to a control group that received potassium chloride with a matched potassium concentration.

The patient population had a mean age of 71 years, 73% were male, 75% were White, 46% had diabetes, and 56% had chronic kidney disease. There was a 13% loss to follow-up, which was attributed to the COVID pandemic.

The amount of contrast administration was 180 mL in the placebo and 170 mL in the nitrate arm, with 50% of patients undergoing some sort of revascularization.

The primary endpoint was the incidence of CIN as defined by KDIGO criteria – a series of stages of acute kidney injury defined by changes in serum creatinine within 72 hours and up to 1 week.

Results showed that this primary CIN endpoint was reduced significantly from 30% in the placebo arm to 9.1% in the nitrate group, a 70% relative risk reduction (P < .0001). The majority (90%) of this CIN was stage 1, but 10% was stage 2.

Consistent results were seen when an alternative definition of CIN (Mehran) was used, although the rates in both arms were lower than when the KDIGO definition was used.

The benefit was seen across prespecified subgroups including diabetes status, troponin positivity, and Mehran risk. But the benefit seemed to be attenuated in patients on preexisting organic nitrate therapy, although the numbers in these groups were too small to draw definitive conclusions.

As would be expected, there were significant elevations in both systemic nitrate and nitrite levels both up to 72 hours after the procedure, which was consistent with the 5-day course. This was associated with reductions in systolic and diastolic blood pressure, but not associated with any adverse events, Dr. Jones reported.

Rates of procedural MI, a prespecified secondary endpoint, were reduced from 12.5% to 4.1% in those on inorganic nitrates (P = .003).

Looking at longer term outcomes, kidney function was improved at 3 months as measured by change in eGFR, which showed a 10% relative improvement of 5.2 mL/min per 1.73 m² (10%) in the nitrate group vs. the placebo group. Serum creatinine levels were also significantly increased in the nitrate group.

At 12 months, there was a significant 50% relative reduction in major adverse cardiovascular events – including all-cause mortality, recurrent MI, and recurrent revascularization – which were reduced from 18.1% in the placebo group to 9.1% in the nitrate group, with a reduction in all three of the constituent components of the composite endpoint including all-cause mortality.

Major adverse kidney events (all-cause mortality, renal replacement therapy, or persistent renal dysfunction) were also reduced at 12 months from 28.4% in the placebo group to 10.7% in the nitrate group (P < .0001), a 60% relative reduction. This was driven by lower rates of all-cause mortality and persistent renal dysfunction.

While Dr. Jones said these results on major cardiovascular and kidney outcomes should be viewed as hypothesis-generating at the present time, he said there were biological mechanisms that could explain these benefits.

“We saw a reduction in procedural MI, and we know there is a lot of similar biology in preventing procedural MI and subsequent cardiac events in the acute phase. This, in combination with the large reduction in acute kidney injury, could explain why there’s improved outcomes out to 12 months.”

In her comments, Dr. Mehran congratulated the investigators on having conducted the first study to have shown benefit in the prevention of contrast-associated acute kidney injury as well as major adverse cardiovascular and kidney events associated with the condition.

She used the term “contrast-associated acute kidney injury” rather than “contrast-induced nephropathy” because, she said, it has not been proven that the acute kidney injury seen after angiography is actually caused by the contrast and “so many other things are occurring during procedures when these patients are presenting with different syndromes.”

Dr. Mehran pointed out some weaknesses in the NITRATE-CIN study including the single-center design, the large volume of contrast administered, 13% of patients missing the primary endpoint blood draw, and an imbalance in relevant baseline characteristics despite randomization.

The NITRATE-CIN study was funded by Heart Research UK. Dr. Jones has disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

AMSTERDAM – A simple, low-cost 5-day course of dietary inorganic nitrate has shown apparent overwhelming benefit in preventing contrast-induced nephropathy (CIN) and reducing subsequent renal and cardiovascular outcomes.

In the NITRATE-CIN Study, non-ST segment elevation myocardial infarction acute coronary syndrome (ACS) patients at risk of renal injury from coronary angiography who received dietary inorganic nitrates had a 70% reduction in CIN compared with those given placebo.

The nitrate group also showed an impressive reduction in periprocedural myocardial infarction (MI) and improved renal function at 3 months, as well as a halving of major adverse cardiovascular events and major adverse kidney events at 1 year.

The trial was presented by Dan Jones, MD, Barts Health NHS Trust, London, at the annual congress of the European Society of Cardiology.

“Currently, aside from intravenous hydration, there is no proven treatment that reduces contrast-induced nephropathy. We feel that dietary inorganic nitrate shows huge promise in this study, and these findings could have important implications in reducing this serious complication of coronary angiography,” Dr. Jones concluded.

He explained that the product used was a formulation of dietary inorganic nitrates given as potassium nitrate capsules, which the study investigators produced specifically for this trial.

At this point, “the only way to get inorganic nitrate is in the diet – specifically by consuming beetroot juice or green leafy vegetables such as spinach and rocket. From a clinician perspective, while these results suggest this is an effective therapy and has great potential, it is not currently possible to prescribe the medication we used in our study, although we are working on producing a commercial product,” he said in an interview.

However, Dr. Jones noted that it is possible to buy beetroot shots, which contain 7 mmol of potassium nitrate in each shot, from health food shops and websites, and two such shots per day for 5 days would give a dose similar to that used in this study, starting the day before angiography.

“While we need a larger multicenter study to confirm these results, studies so far suggest no signal at all that there is any harm in this approach, and there could be a great deal of benefit in taking a couple of beetroot shots prior to and for a few days after an angiogram,” he said.
 

Dietary nitrates “make sense”

Designated discussant of the NITRATE-CIN trial at the ESC Hotline session, Roxanna Mehran, MD, Icahn School of Medicine at Mount Sinai, New York, said the study was well designed, and the “interesting and plausible” hypothesis to raise nitric oxide levels by dietary nitrates “makes sense.”

On the main findings of a major significant 50% reduction in acute kidney injury, Dr. Mehran said, “It is difficult to imagine such a reduction is possible.”

She pointed out that the large reduction in major adverse cardiac events and major adverse kidney events at 1 year also suggests that there is a sustained benefit in protecting the kidney.

“We’re all going to get on beet juice after this,” she quipped.

Still, Dr. Mehran questioned whether the results were “too good to be true,” adding that a larger trial actually powered for longer term outcome events is needed, as well as a better understanding of whether CIN has a causative role in mortality.

Responding to questions about whether such a large effect could actually be achieved with dietary nitrates, Dr. Jones said he thought there would definitely be some benefits, but maybe not quite as large as those seen in this study.

“From our pilot data we thought nitrate may be effective in preventing CIN,” he said in an interview. “We recruited a higher risk group than we thought, which is why the control event rates were higher than we expected, but the acute kidney injury reduction is roughly what we had estimated, and makes sense biologically.”

Dr. Jones acknowledged that the large reductions in long-term major adverse cardiovascular and kidney events were unexpected.

“The trial was not powered to see reductions in these outcomes, so we need to see if those event reductions can be replicated in larger multicenter trials,” he said. “But this was a double-blind placebo-controlled trial so in this trial the effects are real, and I think the effect size in this trial is too large for there not to be a beneficial effect.

“But I’m not so sure that we would see the same magnitude of effect when we have a larger study with tighter confidence intervals but perhaps a 20%-25% reduction in cardiovascular and kidney may be more realistic, which would still be amazing for such an easy and cost-effective intervention,” Dr. Jones added.

A larger trial is now being planned.

The researchers are also working on the development of a commercial form of dietary inorganic nitrate that would be needed for larger multicenter studies and would then be generally available. “We want this to be a low-cost product that would be available to all,” Dr. Jones said.

He noted that other studies have shown that dietary inorganic nitrates in the form of beetroot juice lower blood pressure; there are suggestions it may also lower cholesterol and prevent stent restenosis, and athletes sometimes take it to increase their aerobic capacity.

“There appears to be many benefits of dietary nitrates, and the one thing we can do at this time is to encourage people to increase their dietary nitrate consumption by eating large quantities of green leafy vegetables and beetroot,” Dr. Jones said.
 

Replacing lost nitric oxide

In his presentation, Dr. Jones noted that CIN is a serious complication after coronary angiography and is associated with longer hospital stays, worse long-term kidney function, and increased risk of MI and death.

The incidence varies depending on patient risk and definitions used, but it can affect up to 50% of high-risk ACS patients – older patients and/or those with heart failure, chronic kidney disease, or diabetes.

“We don’t really understand the mechanisms that cause CIN, but multiple proposed mechanisms exist, and we know from previous studies that a deficiency of nitric oxide is crucial to the development of CIN,” he explained. “We also know that [nitric oxide] is crucial for normal renal hemostasis. Therefore, a potential therapeutic target to prevent CIN would be to replace this lost nitric oxide.”

The inorganic nitrate evaluated in this trial is found in the diet, is produced endogenously, and is different from medicinally synthesized organic nitrates such as isosorbide mononitrate, he said.

“Isosorbide mononitrate/dinitrate tablets contain organic nitrates and while they are good for angina, we know that they do not have the same beneficial effects on the sustained generation of nitric oxide as inorganic nitrates,” Dr. Jones added.
 

NITRATE-CIN study

NITRATE-CIN was a double-blind, randomized, placebo-controlled trial conducted at Queen Mary University of London and St. Bartholomew’s Hospital in London, which tested the effectiveness of inorganic nitrate in preventing contrast-induced nephropathy in 640 patients with non-ST elevation ACS referred for invasive coronary angiography.

To be eligible for the trial, patients had to be at risk of contrast-induced nephropathy with an estimated glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m² or have two of the following significant risk factors: diabetes, liver failure, over 70 years of age, exposure to contrast within 7 days, heart failure, or on concomitant renally acting drugs.

Patients were randomly assigned to a formulation of potassium nitrate (12 mmol/744 mg nitrate) per day given as capsules for a 5-day course with the first dose administered prior to angiography or to a control group that received potassium chloride with a matched potassium concentration.

The patient population had a mean age of 71 years, 73% were male, 75% were White, 46% had diabetes, and 56% had chronic kidney disease. There was a 13% loss to follow-up, which was attributed to the COVID pandemic.

The amount of contrast administration was 180 mL in the placebo and 170 mL in the nitrate arm, with 50% of patients undergoing some sort of revascularization.

The primary endpoint was the incidence of CIN as defined by KDIGO criteria – a series of stages of acute kidney injury defined by changes in serum creatinine within 72 hours and up to 1 week.

Results showed that this primary CIN endpoint was reduced significantly from 30% in the placebo arm to 9.1% in the nitrate group, a 70% relative risk reduction (P < .0001). The majority (90%) of this CIN was stage 1, but 10% was stage 2.

Consistent results were seen when an alternative definition of CIN (Mehran) was used, although the rates in both arms were lower than when the KDIGO definition was used.

The benefit was seen across prespecified subgroups including diabetes status, troponin positivity, and Mehran risk. But the benefit seemed to be attenuated in patients on preexisting organic nitrate therapy, although the numbers in these groups were too small to draw definitive conclusions.

As would be expected, there were significant elevations in both systemic nitrate and nitrite levels both up to 72 hours after the procedure, which was consistent with the 5-day course. This was associated with reductions in systolic and diastolic blood pressure, but not associated with any adverse events, Dr. Jones reported.

Rates of procedural MI, a prespecified secondary endpoint, were reduced from 12.5% to 4.1% in those on inorganic nitrates (P = .003).

Looking at longer term outcomes, kidney function was improved at 3 months as measured by change in eGFR, which showed a 10% relative improvement of 5.2 mL/min per 1.73 m² (10%) in the nitrate group vs. the placebo group. Serum creatinine levels were also significantly increased in the nitrate group.

At 12 months, there was a significant 50% relative reduction in major adverse cardiovascular events – including all-cause mortality, recurrent MI, and recurrent revascularization – which were reduced from 18.1% in the placebo group to 9.1% in the nitrate group, with a reduction in all three of the constituent components of the composite endpoint including all-cause mortality.

Major adverse kidney events (all-cause mortality, renal replacement therapy, or persistent renal dysfunction) were also reduced at 12 months from 28.4% in the placebo group to 10.7% in the nitrate group (P < .0001), a 60% relative reduction. This was driven by lower rates of all-cause mortality and persistent renal dysfunction.

While Dr. Jones said these results on major cardiovascular and kidney outcomes should be viewed as hypothesis-generating at the present time, he said there were biological mechanisms that could explain these benefits.

“We saw a reduction in procedural MI, and we know there is a lot of similar biology in preventing procedural MI and subsequent cardiac events in the acute phase. This, in combination with the large reduction in acute kidney injury, could explain why there’s improved outcomes out to 12 months.”

In her comments, Dr. Mehran congratulated the investigators on having conducted the first study to have shown benefit in the prevention of contrast-associated acute kidney injury as well as major adverse cardiovascular and kidney events associated with the condition.

She used the term “contrast-associated acute kidney injury” rather than “contrast-induced nephropathy” because, she said, it has not been proven that the acute kidney injury seen after angiography is actually caused by the contrast and “so many other things are occurring during procedures when these patients are presenting with different syndromes.”

Dr. Mehran pointed out some weaknesses in the NITRATE-CIN study including the single-center design, the large volume of contrast administered, 13% of patients missing the primary endpoint blood draw, and an imbalance in relevant baseline characteristics despite randomization.

The NITRATE-CIN study was funded by Heart Research UK. Dr. Jones has disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Doctors or AI? Lukewarm vote of confidence goes to …

Well, we’ve got some good news for the physicians out there, and we’ve got some bad news. Which do you want first? Okay, we’re mostly hearing good news, so here goes: Most people would choose a human doctor over artificial intelligence for the diagnosis and treatment of their medical conditions.

Alexandra_Koch/Pixabay

And the bad news? In the survey we’re talking about, “most” was 53%, so not exactly a huge victory for the carbon-based life forms. Yup, about 47% of the 2,472 respondents said they would prefer an AI-based clinic over a human specialist, and that number went up if individuals were told that their primary care physicians were on board with AI, “or otherwise nudged to consider AI as good,” the research team said in a written statement released by the University of Arizona, Tucson.

They went on to add that “this signaled the significance of the human physician in guiding a patient’s decision.” So patients will still need their doctors in the future to … um … this is a bit awkward … tell them how good the AI is?

And yes, we know that ChatGPT is already doing the same thing to journalists, but could it write a medical-humor column? Not a chance. Probably can’t even tell a joke.

How do ghosts get rid of wrinkles? Boo-tox. There, let’s see ChatGPT do that.
 

Explaining the joke makes it funnier, right?

Here at LOTME headquarters, we live by one simple rule, passed down directly from the Buddha himself: “Never let a good presurgical assessment of refractory epilepsy go to waste. Also, don’t believe everything you read on the Internet.”

Amy/Pixabay

This human-created joke has been brought to you by the leading theory of humor, which states that comedy stems from our brain reacting to an incongruous part of reality in a positive way. These positive emotions light up our neurons in a specific fashion, and boom, comedy is achieved.

Previous studies into the science of comedy have typically used functional MRI to analyze the brain while it was gripped in the throes of a comedic reaction. Unfortunately, fMRI cannot detect the entirety of the electromagnetic spectrum generated by the brain during these moments, so observing scientists have been, quite literally, missing out on some of the joke. And that’s where a new study from France comes in.

In the study, the researchers showed a group of patients with epilepsy who were hooked up to deep brain electrodes and a high-tech neuroimaging machine – part of the aforementioned presurgical assessment – a 3-minute excerpt from a Charlie Chaplin movie and analyzed their brain activity. Why Charlie Chaplin? Simple. Slapstick is perhaps the most accessible form of comedy across cultures. We can all appreciate a man getting hit in the head with a coconut. The world’s oldest bar joke or whatever this is? Not so much.

During the funniest scenes, all study participants showed increased high-frequency gamma waves (indicating high cognitive engagement) and a decrease in low-frequency waves (indicating reduced inattention and introspection). During unfunny scenes, such as transition moments, the opposite occurred. Importantly, this inverse relationship occurred in the temporal lobe but not in other regions, supporting previous research that indicated humor was mainly processed in the temporal lobe.

The investigators suggested future research should focus on longer videos with more complex forms of comedy, such as jokes, irony, sarcasm, or reference humor. So, uh, a guy getting hit in the head with two coconuts? That’s high-brow stuff right there.
 

Hot take: Humans aren’t that special

We humans have always prided ourselves on being different from “the animals” in an exceptional way. News flash! We aren’t. We may be the apex predator, but new research shows that humans, as part of the animal kingdom, just aren’t special.

jacoblund/iStock/Getty Images

Not special? How can they say that? Are gorillas doing open-heart surgery? Do wolverines tell jokes? At a more basic level, though, the way we operate as mammals in societies is not unique or even new. Elephants are known to mourn their deceased and to have funeral-like practices, ants invented agriculture, and we’re certainly not the only species that has figured out how to use tools.

This new research just demonstrates another way we aren’t exceptional, and that’s in our mating practices and outcomes.

“Humans appear to resemble mammals that live in monogamous partnerships and to some extent, those classified as cooperative breeders, where breeding individuals have to rely on the help of others to raise their offspring,” Monique Borgerhoff Mulder, PhD, professor emerita of anthropology at the University of California, Davis, said in a written statement.

The research team, which consisted of over 100 investigators, looked at 90 human populations based on data from over 80,000 people globally and compared the human data with 49 different nonhuman mammal species. In polygynous societies in which men take several wives, they found, women have more access to resources like food, shelter, and parenting help. Monogamy, on the other hand, “can drive significant inequalities among women,” Dr. Borgerhoff Mulder said, by promoting large differences in the number of children couples produce.

Human day-to-day behavior and child-rearing habits – one parent taking a daughter to ballet class and fixing dinner so the other parent can get to exercise class before picking up the son from soccer practice – may have us thinking that we are part of an evolved society, but really we are not much different than other mammals that hunt, forage for food, and rear and teach their children, the researchers suggested.

So, yes, humans can travel to the moon, create a vaccine for smallpox, and hit other humans with coconuts, but when it comes to simply having offspring or raising them, we’re not all that special. Get over it.

Doctors or AI? Lukewarm vote of confidence goes to …

Well, we’ve got some good news for the physicians out there, and we’ve got some bad news. Which do you want first? Okay, we’re mostly hearing good news, so here goes: Most people would choose a human doctor over artificial intelligence for the diagnosis and treatment of their medical conditions.

Alexandra_Koch/Pixabay

And the bad news? In the survey we’re talking about, “most” was 53%, so not exactly a huge victory for the carbon-based life forms. Yup, about 47% of the 2,472 respondents said they would prefer an AI-based clinic over a human specialist, and that number went up if individuals were told that their primary care physicians were on board with AI, “or otherwise nudged to consider AI as good,” the research team said in a written statement released by the University of Arizona, Tucson.

They went on to add that “this signaled the significance of the human physician in guiding a patient’s decision.” So patients will still need their doctors in the future to … um … this is a bit awkward … tell them how good the AI is?

And yes, we know that ChatGPT is already doing the same thing to journalists, but could it write a medical-humor column? Not a chance. Probably can’t even tell a joke.

How do ghosts get rid of wrinkles? Boo-tox. There, let’s see ChatGPT do that.
 

Explaining the joke makes it funnier, right?

Here at LOTME headquarters, we live by one simple rule, passed down directly from the Buddha himself: “Never let a good presurgical assessment of refractory epilepsy go to waste. Also, don’t believe everything you read on the Internet.”

Amy/Pixabay

This human-created joke has been brought to you by the leading theory of humor, which states that comedy stems from our brain reacting to an incongruous part of reality in a positive way. These positive emotions light up our neurons in a specific fashion, and boom, comedy is achieved.

Previous studies into the science of comedy have typically used functional MRI to analyze the brain while it was gripped in the throes of a comedic reaction. Unfortunately, fMRI cannot detect the entirety of the electromagnetic spectrum generated by the brain during these moments, so observing scientists have been, quite literally, missing out on some of the joke. And that’s where a new study from France comes in.

In the study, the researchers showed a group of patients with epilepsy who were hooked up to deep brain electrodes and a high-tech neuroimaging machine – part of the aforementioned presurgical assessment – a 3-minute excerpt from a Charlie Chaplin movie and analyzed their brain activity. Why Charlie Chaplin? Simple. Slapstick is perhaps the most accessible form of comedy across cultures. We can all appreciate a man getting hit in the head with a coconut. The world’s oldest bar joke or whatever this is? Not so much.

During the funniest scenes, all study participants showed increased high-frequency gamma waves (indicating high cognitive engagement) and a decrease in low-frequency waves (indicating reduced inattention and introspection). During unfunny scenes, such as transition moments, the opposite occurred. Importantly, this inverse relationship occurred in the temporal lobe but not in other regions, supporting previous research that indicated humor was mainly processed in the temporal lobe.

The investigators suggested future research should focus on longer videos with more complex forms of comedy, such as jokes, irony, sarcasm, or reference humor. So, uh, a guy getting hit in the head with two coconuts? That’s high-brow stuff right there.
 

Hot take: Humans aren’t that special

We humans have always prided ourselves on being different from “the animals” in an exceptional way. News flash! We aren’t. We may be the apex predator, but new research shows that humans, as part of the animal kingdom, just aren’t special.

jacoblund/iStock/Getty Images

Not special? How can they say that? Are gorillas doing open-heart surgery? Do wolverines tell jokes? At a more basic level, though, the way we operate as mammals in societies is not unique or even new. Elephants are known to mourn their deceased and to have funeral-like practices, ants invented agriculture, and we’re certainly not the only species that has figured out how to use tools.

This new research just demonstrates another way we aren’t exceptional, and that’s in our mating practices and outcomes.

“Humans appear to resemble mammals that live in monogamous partnerships and to some extent, those classified as cooperative breeders, where breeding individuals have to rely on the help of others to raise their offspring,” Monique Borgerhoff Mulder, PhD, professor emerita of anthropology at the University of California, Davis, said in a written statement.

The research team, which consisted of over 100 investigators, looked at 90 human populations based on data from over 80,000 people globally and compared the human data with 49 different nonhuman mammal species. In polygynous societies in which men take several wives, they found, women have more access to resources like food, shelter, and parenting help. Monogamy, on the other hand, “can drive significant inequalities among women,” Dr. Borgerhoff Mulder said, by promoting large differences in the number of children couples produce.

Human day-to-day behavior and child-rearing habits – one parent taking a daughter to ballet class and fixing dinner so the other parent can get to exercise class before picking up the son from soccer practice – may have us thinking that we are part of an evolved society, but really we are not much different than other mammals that hunt, forage for food, and rear and teach their children, the researchers suggested.

So, yes, humans can travel to the moon, create a vaccine for smallpox, and hit other humans with coconuts, but when it comes to simply having offspring or raising them, we’re not all that special. Get over it.

Doctors or AI? Lukewarm vote of confidence goes to …

Well, we’ve got some good news for the physicians out there, and we’ve got some bad news. Which do you want first? Okay, we’re mostly hearing good news, so here goes: Most people would choose a human doctor over artificial intelligence for the diagnosis and treatment of their medical conditions.

Alexandra_Koch/Pixabay

And the bad news? In the survey we’re talking about, “most” was 53%, so not exactly a huge victory for the carbon-based life forms. Yup, about 47% of the 2,472 respondents said they would prefer an AI-based clinic over a human specialist, and that number went up if individuals were told that their primary care physicians were on board with AI, “or otherwise nudged to consider AI as good,” the research team said in a written statement released by the University of Arizona, Tucson.

They went on to add that “this signaled the significance of the human physician in guiding a patient’s decision.” So patients will still need their doctors in the future to … um … this is a bit awkward … tell them how good the AI is?

And yes, we know that ChatGPT is already doing the same thing to journalists, but could it write a medical-humor column? Not a chance. Probably can’t even tell a joke.

How do ghosts get rid of wrinkles? Boo-tox. There, let’s see ChatGPT do that.
 

Explaining the joke makes it funnier, right?

Here at LOTME headquarters, we live by one simple rule, passed down directly from the Buddha himself: “Never let a good presurgical assessment of refractory epilepsy go to waste. Also, don’t believe everything you read on the Internet.”

Amy/Pixabay

This human-created joke has been brought to you by the leading theory of humor, which states that comedy stems from our brain reacting to an incongruous part of reality in a positive way. These positive emotions light up our neurons in a specific fashion, and boom, comedy is achieved.

Previous studies into the science of comedy have typically used functional MRI to analyze the brain while it was gripped in the throes of a comedic reaction. Unfortunately, fMRI cannot detect the entirety of the electromagnetic spectrum generated by the brain during these moments, so observing scientists have been, quite literally, missing out on some of the joke. And that’s where a new study from France comes in.

In the study, the researchers showed a group of patients with epilepsy who were hooked up to deep brain electrodes and a high-tech neuroimaging machine – part of the aforementioned presurgical assessment – a 3-minute excerpt from a Charlie Chaplin movie and analyzed their brain activity. Why Charlie Chaplin? Simple. Slapstick is perhaps the most accessible form of comedy across cultures. We can all appreciate a man getting hit in the head with a coconut. The world’s oldest bar joke or whatever this is? Not so much.

During the funniest scenes, all study participants showed increased high-frequency gamma waves (indicating high cognitive engagement) and a decrease in low-frequency waves (indicating reduced inattention and introspection). During unfunny scenes, such as transition moments, the opposite occurred. Importantly, this inverse relationship occurred in the temporal lobe but not in other regions, supporting previous research that indicated humor was mainly processed in the temporal lobe.

The investigators suggested future research should focus on longer videos with more complex forms of comedy, such as jokes, irony, sarcasm, or reference humor. So, uh, a guy getting hit in the head with two coconuts? That’s high-brow stuff right there.
 

Hot take: Humans aren’t that special

We humans have always prided ourselves on being different from “the animals” in an exceptional way. News flash! We aren’t. We may be the apex predator, but new research shows that humans, as part of the animal kingdom, just aren’t special.

jacoblund/iStock/Getty Images

Not special? How can they say that? Are gorillas doing open-heart surgery? Do wolverines tell jokes? At a more basic level, though, the way we operate as mammals in societies is not unique or even new. Elephants are known to mourn their deceased and to have funeral-like practices, ants invented agriculture, and we’re certainly not the only species that has figured out how to use tools.

This new research just demonstrates another way we aren’t exceptional, and that’s in our mating practices and outcomes.

“Humans appear to resemble mammals that live in monogamous partnerships and to some extent, those classified as cooperative breeders, where breeding individuals have to rely on the help of others to raise their offspring,” Monique Borgerhoff Mulder, PhD, professor emerita of anthropology at the University of California, Davis, said in a written statement.

The research team, which consisted of over 100 investigators, looked at 90 human populations based on data from over 80,000 people globally and compared the human data with 49 different nonhuman mammal species. In polygynous societies in which men take several wives, they found, women have more access to resources like food, shelter, and parenting help. Monogamy, on the other hand, “can drive significant inequalities among women,” Dr. Borgerhoff Mulder said, by promoting large differences in the number of children couples produce.

Human day-to-day behavior and child-rearing habits – one parent taking a daughter to ballet class and fixing dinner so the other parent can get to exercise class before picking up the son from soccer practice – may have us thinking that we are part of an evolved society, but really we are not much different than other mammals that hunt, forage for food, and rear and teach their children, the researchers suggested.

So, yes, humans can travel to the moon, create a vaccine for smallpox, and hit other humans with coconuts, but when it comes to simply having offspring or raising them, we’re not all that special. Get over it.

A novel artificial intelligence (AI) algorithm shows promise for estimating left ventricular ejection function (LVEF) using routinely obtained left coronary artery angiogram videos, a new study suggests.

In the test dataset, the video-based algorithm, called a deep neural network (DNN), discriminated reduced LVEF (< 40%) with an area under the receiver operating characteristic curve of 0.911.

In the external validation dataset, the DNN discriminated reduced LVEF with an AUROC of 0.906. However, the DNN tended to overestimate low LVEFs and to underestimate high LVEFs.

“We know the findings will be unexpected for cardiologists who don’t typically expect to get an estimate of systolic function or pump function just from an angiogram,” principal investigator Geoffrey H. Tison, MD, of the University of California, San Francisco, said in an interview.

In fact, he noted, “one of the challenges we face is a lack of trust by the health care community. They may not understand what drives the predictions behind our models. We have to translate that information in such a way that physicians trust that the algorithm is using the right features from the data they feed in to make the predictions.”

To help bolster that trust, “we display the ‘Model Facts,’ a nutrition-style label that describes how we train the algorithm, how it was validated, and the inclusion and exclusion criteria,” added lead author Robert Avram, MD, of the University of Montreal.

Model Facts is a safeguard against inappropriate use of the algorithm, Dr. Avram said. For example, if the algorithm was trained on patients between the ages of 40 and 90 and a clinician fed in data for a 35-year-old, a pop-up would appear warning the physician that the data being inputted are different from the data the algorithm was trained and validated on, and so any prediction “should be taken with a grain of salt.”

The study was published online in JAMA Cardiology.
 

Additional procedure

LVEF can be determined before coronary angiography with transthoracic echocardiography, but that is not always available, particularly for patients being seen emergently for acute coronary syndromes, the researchers wrote. LVEF can also be assessed using left ventriculography, an additional procedure that requires insertion of a pigtail catheter into the left ventricle and injection of more contrast and longer radiation exposure.

“Novel methods to assess LVEF at the point of care during coronary angiography would expand the available options to perform this important physiologic determination,” they wrote. “Video-based deep neural networks can learn subtle patterns from medical data to accomplish certain tasks beyond what physicians can achieve with that data, providing an opportunity to assess cardiac systolic function in real time from standard angiographic images without additional cost or procedures.”

The investigators conducted a cross-sectional study using UCSF patient data from 2012 to 2019. Data were randomly categorized into training, development, and test datasets.

External validation data were obtained from the University of Ottawa Heart Institute.

All adult patients who received a coronary angiogram and a transthoracic echocardiogram (TTE) within 3 months before or 1 month after receiving the angiogram were included.

A total of 4,042 angiograms with corresponding TTE LVEF from 3,679 UCSF patients were included in the analysis. The mean age of the patients was 64.3 years, and 65% were men.

The researchers’ video-based DNN, called CathEF, was used to discriminate reduced LVEF and to predict a continuous LVEF percentage from standard angiogram videos of the left coronary artery.

In the UCSF test dataset, CathEF discriminated reduced LVEF with an AUROC of 0.911; the diagnostic odds ratio for reduced LVEF was 22.7.

Furthermore, the CathEF-predicted that LVEF had a mean absolute error (MAE) of 8.5%, compared with TTE LVEF.

The CathEF-predicted LVEF differed 5% or less in comparison with the TTE LVEF in 38% of the test dataset studies; however, differences greater than 15% were seen in 15.2% of cases.

In the external validation, CathEF discriminated reduced LVEF with an AUROC of 0.906 and an MAE of 7%.

CathEF performance was consistent irrespective of patient characteristics, including sex, body mass index, low estimated glomerular filtration rate (< 45), acute coronary syndromes, obstructive coronary artery disease, and left ventricular hypertrophy.

However, as noted, it tended to overestimate low LVEFs and to underestimate high LVEFs.

“Further research can improve accuracy and reduce the variability of DNNs to maximize their clinical utility,” the authors concluded.

A validation study is underway at the Montreal Heart Institute, and similar studies are planned at UCSF and McGill University, Dr. Tison said. “We expect to present preliminary findings at medical conferences either before the end of the year or maybe for the American College of Cardiology meeting in March 2024.”
 

Potentially improved outcomes

In a comment, Alfonso H. Waller, MD, a member of the American College of Cardiology’s Imaging Council and director of cardiac imaging at New Jersey Medical School, Newark, said that, “at some centers, in patients presenting with an acute ST-segment elevation myocardial infarction, some argue that assessment of myocardial and valvular function with [left ventriculography] grams may provide important prognostic information and in part may help guide the management of the patient.

“Therefore, this novel approach may provide information that is not usually available without performing a classic LV gram ... [and] may lead to improved delivery of care, earlier therapies, and potentially improved outcomes and quality of life.”

If the technology is available in real time, “it could enable real-time, dynamic assessment of cardiac function during coronary angiography, which may be particularly helpful in acute STEMI cases where baseline cardiac function and renal function may be unknown and additional contrast may be detrimental,” he said.

However, patients who might benefit most from the technology are those with severely reduced LVEF, “and unfortunately, the LVEF may be overestimated in this group,” he said.

Dr. Waller also noted that the model was developed using echocardiograms obtained 3 months before or up to 1 month after the angiogram, during which time “LVEF may change significantly. Typically, if someone presents with an acute coronary syndrome, there can be myocardial stunning, which can lead to regional wall motion abnormalities and lowering of LVEF.”

The validation study is evaluating patients with acute coronary syndrome for whom an echocardiogram was performed within 48 hours of the angiogram, he added.

The study was supported by grants from the Fonds de la Recherche en Santé du Québec, the Montreal Heart Institute Research Centre, the Montreal Heart Institute Foundation, the Des Groseillers-Bérard Research Chair, the National Institutes of Health, and the Heart and Stroke Foundation of Ontario. Dr. Tison, Dr. Avram, and Dr. Waller disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

A novel artificial intelligence (AI) algorithm shows promise for estimating left ventricular ejection function (LVEF) using routinely obtained left coronary artery angiogram videos, a new study suggests.

In the test dataset, the video-based algorithm, called a deep neural network (DNN), discriminated reduced LVEF (< 40%) with an area under the receiver operating characteristic curve of 0.911.

In the external validation dataset, the DNN discriminated reduced LVEF with an AUROC of 0.906. However, the DNN tended to overestimate low LVEFs and to underestimate high LVEFs.

“We know the findings will be unexpected for cardiologists who don’t typically expect to get an estimate of systolic function or pump function just from an angiogram,” principal investigator Geoffrey H. Tison, MD, of the University of California, San Francisco, said in an interview.

In fact, he noted, “one of the challenges we face is a lack of trust by the health care community. They may not understand what drives the predictions behind our models. We have to translate that information in such a way that physicians trust that the algorithm is using the right features from the data they feed in to make the predictions.”

To help bolster that trust, “we display the ‘Model Facts,’ a nutrition-style label that describes how we train the algorithm, how it was validated, and the inclusion and exclusion criteria,” added lead author Robert Avram, MD, of the University of Montreal.

Model Facts is a safeguard against inappropriate use of the algorithm, Dr. Avram said. For example, if the algorithm was trained on patients between the ages of 40 and 90 and a clinician fed in data for a 35-year-old, a pop-up would appear warning the physician that the data being inputted are different from the data the algorithm was trained and validated on, and so any prediction “should be taken with a grain of salt.”

The study was published online in JAMA Cardiology.
 

Additional procedure

LVEF can be determined before coronary angiography with transthoracic echocardiography, but that is not always available, particularly for patients being seen emergently for acute coronary syndromes, the researchers wrote. LVEF can also be assessed using left ventriculography, an additional procedure that requires insertion of a pigtail catheter into the left ventricle and injection of more contrast and longer radiation exposure.

“Novel methods to assess LVEF at the point of care during coronary angiography would expand the available options to perform this important physiologic determination,” they wrote. “Video-based deep neural networks can learn subtle patterns from medical data to accomplish certain tasks beyond what physicians can achieve with that data, providing an opportunity to assess cardiac systolic function in real time from standard angiographic images without additional cost or procedures.”

The investigators conducted a cross-sectional study using UCSF patient data from 2012 to 2019. Data were randomly categorized into training, development, and test datasets.

External validation data were obtained from the University of Ottawa Heart Institute.

All adult patients who received a coronary angiogram and a transthoracic echocardiogram (TTE) within 3 months before or 1 month after receiving the angiogram were included.

A total of 4,042 angiograms with corresponding TTE LVEF from 3,679 UCSF patients were included in the analysis. The mean age of the patients was 64.3 years, and 65% were men.

The researchers’ video-based DNN, called CathEF, was used to discriminate reduced LVEF and to predict a continuous LVEF percentage from standard angiogram videos of the left coronary artery.

In the UCSF test dataset, CathEF discriminated reduced LVEF with an AUROC of 0.911; the diagnostic odds ratio for reduced LVEF was 22.7.

Furthermore, the CathEF-predicted that LVEF had a mean absolute error (MAE) of 8.5%, compared with TTE LVEF.

The CathEF-predicted LVEF differed 5% or less in comparison with the TTE LVEF in 38% of the test dataset studies; however, differences greater than 15% were seen in 15.2% of cases.

In the external validation, CathEF discriminated reduced LVEF with an AUROC of 0.906 and an MAE of 7%.

CathEF performance was consistent irrespective of patient characteristics, including sex, body mass index, low estimated glomerular filtration rate (< 45), acute coronary syndromes, obstructive coronary artery disease, and left ventricular hypertrophy.

However, as noted, it tended to overestimate low LVEFs and to underestimate high LVEFs.

“Further research can improve accuracy and reduce the variability of DNNs to maximize their clinical utility,” the authors concluded.

A validation study is underway at the Montreal Heart Institute, and similar studies are planned at UCSF and McGill University, Dr. Tison said. “We expect to present preliminary findings at medical conferences either before the end of the year or maybe for the American College of Cardiology meeting in March 2024.”
 

Potentially improved outcomes

In a comment, Alfonso H. Waller, MD, a member of the American College of Cardiology’s Imaging Council and director of cardiac imaging at New Jersey Medical School, Newark, said that, “at some centers, in patients presenting with an acute ST-segment elevation myocardial infarction, some argue that assessment of myocardial and valvular function with [left ventriculography] grams may provide important prognostic information and in part may help guide the management of the patient.

“Therefore, this novel approach may provide information that is not usually available without performing a classic LV gram ... [and] may lead to improved delivery of care, earlier therapies, and potentially improved outcomes and quality of life.”

If the technology is available in real time, “it could enable real-time, dynamic assessment of cardiac function during coronary angiography, which may be particularly helpful in acute STEMI cases where baseline cardiac function and renal function may be unknown and additional contrast may be detrimental,” he said.

However, patients who might benefit most from the technology are those with severely reduced LVEF, “and unfortunately, the LVEF may be overestimated in this group,” he said.

Dr. Waller also noted that the model was developed using echocardiograms obtained 3 months before or up to 1 month after the angiogram, during which time “LVEF may change significantly. Typically, if someone presents with an acute coronary syndrome, there can be myocardial stunning, which can lead to regional wall motion abnormalities and lowering of LVEF.”

The validation study is evaluating patients with acute coronary syndrome for whom an echocardiogram was performed within 48 hours of the angiogram, he added.

The study was supported by grants from the Fonds de la Recherche en Santé du Québec, the Montreal Heart Institute Research Centre, the Montreal Heart Institute Foundation, the Des Groseillers-Bérard Research Chair, the National Institutes of Health, and the Heart and Stroke Foundation of Ontario. Dr. Tison, Dr. Avram, and Dr. Waller disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

A novel artificial intelligence (AI) algorithm shows promise for estimating left ventricular ejection function (LVEF) using routinely obtained left coronary artery angiogram videos, a new study suggests.

In the test dataset, the video-based algorithm, called a deep neural network (DNN), discriminated reduced LVEF (< 40%) with an area under the receiver operating characteristic curve of 0.911.

In the external validation dataset, the DNN discriminated reduced LVEF with an AUROC of 0.906. However, the DNN tended to overestimate low LVEFs and to underestimate high LVEFs.

“We know the findings will be unexpected for cardiologists who don’t typically expect to get an estimate of systolic function or pump function just from an angiogram,” principal investigator Geoffrey H. Tison, MD, of the University of California, San Francisco, said in an interview.

In fact, he noted, “one of the challenges we face is a lack of trust by the health care community. They may not understand what drives the predictions behind our models. We have to translate that information in such a way that physicians trust that the algorithm is using the right features from the data they feed in to make the predictions.”

To help bolster that trust, “we display the ‘Model Facts,’ a nutrition-style label that describes how we train the algorithm, how it was validated, and the inclusion and exclusion criteria,” added lead author Robert Avram, MD, of the University of Montreal.

Model Facts is a safeguard against inappropriate use of the algorithm, Dr. Avram said. For example, if the algorithm was trained on patients between the ages of 40 and 90 and a clinician fed in data for a 35-year-old, a pop-up would appear warning the physician that the data being inputted are different from the data the algorithm was trained and validated on, and so any prediction “should be taken with a grain of salt.”

The study was published online in JAMA Cardiology.
 

Additional procedure

LVEF can be determined before coronary angiography with transthoracic echocardiography, but that is not always available, particularly for patients being seen emergently for acute coronary syndromes, the researchers wrote. LVEF can also be assessed using left ventriculography, an additional procedure that requires insertion of a pigtail catheter into the left ventricle and injection of more contrast and longer radiation exposure.

“Novel methods to assess LVEF at the point of care during coronary angiography would expand the available options to perform this important physiologic determination,” they wrote. “Video-based deep neural networks can learn subtle patterns from medical data to accomplish certain tasks beyond what physicians can achieve with that data, providing an opportunity to assess cardiac systolic function in real time from standard angiographic images without additional cost or procedures.”

The investigators conducted a cross-sectional study using UCSF patient data from 2012 to 2019. Data were randomly categorized into training, development, and test datasets.

External validation data were obtained from the University of Ottawa Heart Institute.

All adult patients who received a coronary angiogram and a transthoracic echocardiogram (TTE) within 3 months before or 1 month after receiving the angiogram were included.

A total of 4,042 angiograms with corresponding TTE LVEF from 3,679 UCSF patients were included in the analysis. The mean age of the patients was 64.3 years, and 65% were men.

The researchers’ video-based DNN, called CathEF, was used to discriminate reduced LVEF and to predict a continuous LVEF percentage from standard angiogram videos of the left coronary artery.

In the UCSF test dataset, CathEF discriminated reduced LVEF with an AUROC of 0.911; the diagnostic odds ratio for reduced LVEF was 22.7.

Furthermore, the CathEF-predicted that LVEF had a mean absolute error (MAE) of 8.5%, compared with TTE LVEF.

The CathEF-predicted LVEF differed 5% or less in comparison with the TTE LVEF in 38% of the test dataset studies; however, differences greater than 15% were seen in 15.2% of cases.

In the external validation, CathEF discriminated reduced LVEF with an AUROC of 0.906 and an MAE of 7%.

CathEF performance was consistent irrespective of patient characteristics, including sex, body mass index, low estimated glomerular filtration rate (< 45), acute coronary syndromes, obstructive coronary artery disease, and left ventricular hypertrophy.

However, as noted, it tended to overestimate low LVEFs and to underestimate high LVEFs.

“Further research can improve accuracy and reduce the variability of DNNs to maximize their clinical utility,” the authors concluded.

A validation study is underway at the Montreal Heart Institute, and similar studies are planned at UCSF and McGill University, Dr. Tison said. “We expect to present preliminary findings at medical conferences either before the end of the year or maybe for the American College of Cardiology meeting in March 2024.”
 

Potentially improved outcomes

In a comment, Alfonso H. Waller, MD, a member of the American College of Cardiology’s Imaging Council and director of cardiac imaging at New Jersey Medical School, Newark, said that, “at some centers, in patients presenting with an acute ST-segment elevation myocardial infarction, some argue that assessment of myocardial and valvular function with [left ventriculography] grams may provide important prognostic information and in part may help guide the management of the patient.

“Therefore, this novel approach may provide information that is not usually available without performing a classic LV gram ... [and] may lead to improved delivery of care, earlier therapies, and potentially improved outcomes and quality of life.”

If the technology is available in real time, “it could enable real-time, dynamic assessment of cardiac function during coronary angiography, which may be particularly helpful in acute STEMI cases where baseline cardiac function and renal function may be unknown and additional contrast may be detrimental,” he said.

However, patients who might benefit most from the technology are those with severely reduced LVEF, “and unfortunately, the LVEF may be overestimated in this group,” he said.

Dr. Waller also noted that the model was developed using echocardiograms obtained 3 months before or up to 1 month after the angiogram, during which time “LVEF may change significantly. Typically, if someone presents with an acute coronary syndrome, there can be myocardial stunning, which can lead to regional wall motion abnormalities and lowering of LVEF.”

The validation study is evaluating patients with acute coronary syndrome for whom an echocardiogram was performed within 48 hours of the angiogram, he added.

The study was supported by grants from the Fonds de la Recherche en Santé du Québec, the Montreal Heart Institute Research Centre, the Montreal Heart Institute Foundation, the Des Groseillers-Bérard Research Chair, the National Institutes of Health, and the Heart and Stroke Foundation of Ontario. Dr. Tison, Dr. Avram, and Dr. Waller disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The largest multicenter randomized trial to date of CT angiography before left atrial appendage closure (LAAC) to treat atrial fibrillation has added to the evidence that the imaging technique on top of transesophageal echocardiography achieves a higher degree of short- and long-term success than TEE alone.

The results are from a subanalysis of the Swiss-Apero trial, a randomized comparative trial of the Watchman and Amulet devices for LAAC, which published results in Circulation.

“Our observational data support to use of CT for LAAC procedure planning,” senior investigator Lorenz Räber, MD, PhD, said in an interview. “This is not very surprising given the high variability of the LAA anatomy and the associated complexity of the procedure.” Dr. Räber is director of the catheterization laboratory at Inselspital, Bern (Switzerland) University Hospital.

The study, published online in JACC: Cardiovascular Interventions, included 219 LAAC procedures in which the operators performed coronary CT angiography (CTTA) beforehand. When the investigators designed the study, LAAC procedures were typically planned using TEE alone, and so participating operators were blinded to preprocedural CCTA imaging. Soon after the study launch, European cardiology societies issued a consensus statement that included CCTA as an option for procedure planning. So the Swiss-Apero investigators changed the subanalysis protocol to unblind the operators – that is, they were permitted to plan LAAC procedures with CCTA imaging in addition to TEE. In this subanalysis, most patients had implantation with blinding to CCTA (57.9% vs. 41.2%).
 

Study results

The subanalysis determined that operator unblinding to preprocedural CCTA resulted in better success with LAAC, both in the short term, at 93.5% vs. 81.1% (P = .009; adjusted odds ratio, 2.76; 95% confidence interval, 1.05-7.29; P = .40) and the long term, at 83.7% vs. 72.4% (P = .050; aOR, 2.12; 95% CI, 1.03-4.35; P = .041).

Dr. Räber noted that this is only the third study to date that examined the potential impact of preprocedural CCTA plus TEE. One was a small study of 24 consecutive LAAC procedures with the Watchman device that compared TEE alone and CCTA plus TEE, finding better outcomes in the group that had both imaging modalities . A larger, single-center cohort study of 485 LAAC Watchman procedures found that CCTA resulted in faster operation times and higher successful device implantation rates, but no significant difference in procedural complications.

Dr. Räber explained why his group’s subanalysis may have found a clinical benefit with CCTA on top of TEE. “Our study was much larger, as compared to the randomized clinical trial, and there was no selection bias as in the second study mentioned before, as operators did not have the option to decide whether or not to assess the CCTA prior to the procedure,” he said. “Finally, in the previous studies there was no random allocation of device type” – that is, Amulet versus Watchman.

One study limitation Dr. Räber noted was that significantly more patients in the blinded group were discharged with dual-antiplatelet therapy. “The lower rate of procedure complications observed in unblinded procedures was mostly driven by a lower number of major bleedings and in particular of pericardial tamponade,” he said. “We cannot therefore exclude that the higher percentage of patients under dual-antiplatelet therapy in the CCTA-blinded group might have favored this difference.”

However, he noted the investigators corrected their analysis to account for differences between the groups. “Importantly, the numerical excess in major procedural bleeding was observed within both the single-antiplatelet therapy and dual-antiplatelet therapy subgroups of the TEE-only group.”

In an accompanying editorial, coauthors Brian O’Neill, MD, and Dee Dee Wang, MD, both with the Center for Structural Heard Disease at Henry Ford Hospital in Detroit, noted that the Swiss-Apero subanalysis “reinforced” the benefit of CCTA before LAAC.  

“This study demonstrated, for the first time, improved short- and long-term procedural success using CT in addition to TEE for left atrial appendage occlusion,” Dr. O’Neill said in an interview. “This particular study may serve as a guide to an adequately powered randomized trial of CT versus TEE in left atrial appendage occlusion.” Future LAAC trials should incorporate preprocedural CCTA.

Dr. O’Neill noted that, as a subanalysis of a randomized trial, the “results are hypothesis generating.” However, he added, “the results are in line with several previous studies of CT versus TEE in left atrial appendage occlusion.”

Dr Räber disclosed financial relationships with Abbott Vascular, Boston Scientific, Biotronik, Infraredx, Heartflow, Sanofi, Regeneron, Amgen, AstraZeneca, CSL Behring, Canon, Occlutech, and Vifor. Dr. O’Neill disclosed financial relationships with Edwards Lifesciences, Medtronic, and Abbott Vascular.

The largest multicenter randomized trial to date of CT angiography before left atrial appendage closure (LAAC) to treat atrial fibrillation has added to the evidence that the imaging technique on top of transesophageal echocardiography achieves a higher degree of short- and long-term success than TEE alone.

The results are from a subanalysis of the Swiss-Apero trial, a randomized comparative trial of the Watchman and Amulet devices for LAAC, which published results in Circulation.

“Our observational data support to use of CT for LAAC procedure planning,” senior investigator Lorenz Räber, MD, PhD, said in an interview. “This is not very surprising given the high variability of the LAA anatomy and the associated complexity of the procedure.” Dr. Räber is director of the catheterization laboratory at Inselspital, Bern (Switzerland) University Hospital.

The study, published online in JACC: Cardiovascular Interventions, included 219 LAAC procedures in which the operators performed coronary CT angiography (CTTA) beforehand. When the investigators designed the study, LAAC procedures were typically planned using TEE alone, and so participating operators were blinded to preprocedural CCTA imaging. Soon after the study launch, European cardiology societies issued a consensus statement that included CCTA as an option for procedure planning. So the Swiss-Apero investigators changed the subanalysis protocol to unblind the operators – that is, they were permitted to plan LAAC procedures with CCTA imaging in addition to TEE. In this subanalysis, most patients had implantation with blinding to CCTA (57.9% vs. 41.2%).
 

Study results

The subanalysis determined that operator unblinding to preprocedural CCTA resulted in better success with LAAC, both in the short term, at 93.5% vs. 81.1% (P = .009; adjusted odds ratio, 2.76; 95% confidence interval, 1.05-7.29; P = .40) and the long term, at 83.7% vs. 72.4% (P = .050; aOR, 2.12; 95% CI, 1.03-4.35; P = .041).

Dr. Räber noted that this is only the third study to date that examined the potential impact of preprocedural CCTA plus TEE. One was a small study of 24 consecutive LAAC procedures with the Watchman device that compared TEE alone and CCTA plus TEE, finding better outcomes in the group that had both imaging modalities . A larger, single-center cohort study of 485 LAAC Watchman procedures found that CCTA resulted in faster operation times and higher successful device implantation rates, but no significant difference in procedural complications.

Dr. Räber explained why his group’s subanalysis may have found a clinical benefit with CCTA on top of TEE. “Our study was much larger, as compared to the randomized clinical trial, and there was no selection bias as in the second study mentioned before, as operators did not have the option to decide whether or not to assess the CCTA prior to the procedure,” he said. “Finally, in the previous studies there was no random allocation of device type” – that is, Amulet versus Watchman.

One study limitation Dr. Räber noted was that significantly more patients in the blinded group were discharged with dual-antiplatelet therapy. “The lower rate of procedure complications observed in unblinded procedures was mostly driven by a lower number of major bleedings and in particular of pericardial tamponade,” he said. “We cannot therefore exclude that the higher percentage of patients under dual-antiplatelet therapy in the CCTA-blinded group might have favored this difference.”

However, he noted the investigators corrected their analysis to account for differences between the groups. “Importantly, the numerical excess in major procedural bleeding was observed within both the single-antiplatelet therapy and dual-antiplatelet therapy subgroups of the TEE-only group.”

In an accompanying editorial, coauthors Brian O’Neill, MD, and Dee Dee Wang, MD, both with the Center for Structural Heard Disease at Henry Ford Hospital in Detroit, noted that the Swiss-Apero subanalysis “reinforced” the benefit of CCTA before LAAC.  

“This study demonstrated, for the first time, improved short- and long-term procedural success using CT in addition to TEE for left atrial appendage occlusion,” Dr. O’Neill said in an interview. “This particular study may serve as a guide to an adequately powered randomized trial of CT versus TEE in left atrial appendage occlusion.” Future LAAC trials should incorporate preprocedural CCTA.

Dr. O’Neill noted that, as a subanalysis of a randomized trial, the “results are hypothesis generating.” However, he added, “the results are in line with several previous studies of CT versus TEE in left atrial appendage occlusion.”

Dr Räber disclosed financial relationships with Abbott Vascular, Boston Scientific, Biotronik, Infraredx, Heartflow, Sanofi, Regeneron, Amgen, AstraZeneca, CSL Behring, Canon, Occlutech, and Vifor. Dr. O’Neill disclosed financial relationships with Edwards Lifesciences, Medtronic, and Abbott Vascular.

The largest multicenter randomized trial to date of CT angiography before left atrial appendage closure (LAAC) to treat atrial fibrillation has added to the evidence that the imaging technique on top of transesophageal echocardiography achieves a higher degree of short- and long-term success than TEE alone.

The results are from a subanalysis of the Swiss-Apero trial, a randomized comparative trial of the Watchman and Amulet devices for LAAC, which published results in Circulation.

“Our observational data support to use of CT for LAAC procedure planning,” senior investigator Lorenz Räber, MD, PhD, said in an interview. “This is not very surprising given the high variability of the LAA anatomy and the associated complexity of the procedure.” Dr. Räber is director of the catheterization laboratory at Inselspital, Bern (Switzerland) University Hospital.

The study, published online in JACC: Cardiovascular Interventions, included 219 LAAC procedures in which the operators performed coronary CT angiography (CTTA) beforehand. When the investigators designed the study, LAAC procedures were typically planned using TEE alone, and so participating operators were blinded to preprocedural CCTA imaging. Soon after the study launch, European cardiology societies issued a consensus statement that included CCTA as an option for procedure planning. So the Swiss-Apero investigators changed the subanalysis protocol to unblind the operators – that is, they were permitted to plan LAAC procedures with CCTA imaging in addition to TEE. In this subanalysis, most patients had implantation with blinding to CCTA (57.9% vs. 41.2%).
 

Study results

The subanalysis determined that operator unblinding to preprocedural CCTA resulted in better success with LAAC, both in the short term, at 93.5% vs. 81.1% (P = .009; adjusted odds ratio, 2.76; 95% confidence interval, 1.05-7.29; P = .40) and the long term, at 83.7% vs. 72.4% (P = .050; aOR, 2.12; 95% CI, 1.03-4.35; P = .041).

Dr. Räber noted that this is only the third study to date that examined the potential impact of preprocedural CCTA plus TEE. One was a small study of 24 consecutive LAAC procedures with the Watchman device that compared TEE alone and CCTA plus TEE, finding better outcomes in the group that had both imaging modalities . A larger, single-center cohort study of 485 LAAC Watchman procedures found that CCTA resulted in faster operation times and higher successful device implantation rates, but no significant difference in procedural complications.

Dr. Räber explained why his group’s subanalysis may have found a clinical benefit with CCTA on top of TEE. “Our study was much larger, as compared to the randomized clinical trial, and there was no selection bias as in the second study mentioned before, as operators did not have the option to decide whether or not to assess the CCTA prior to the procedure,” he said. “Finally, in the previous studies there was no random allocation of device type” – that is, Amulet versus Watchman.

One study limitation Dr. Räber noted was that significantly more patients in the blinded group were discharged with dual-antiplatelet therapy. “The lower rate of procedure complications observed in unblinded procedures was mostly driven by a lower number of major bleedings and in particular of pericardial tamponade,” he said. “We cannot therefore exclude that the higher percentage of patients under dual-antiplatelet therapy in the CCTA-blinded group might have favored this difference.”

However, he noted the investigators corrected their analysis to account for differences between the groups. “Importantly, the numerical excess in major procedural bleeding was observed within both the single-antiplatelet therapy and dual-antiplatelet therapy subgroups of the TEE-only group.”

In an accompanying editorial, coauthors Brian O’Neill, MD, and Dee Dee Wang, MD, both with the Center for Structural Heard Disease at Henry Ford Hospital in Detroit, noted that the Swiss-Apero subanalysis “reinforced” the benefit of CCTA before LAAC.  

“This study demonstrated, for the first time, improved short- and long-term procedural success using CT in addition to TEE for left atrial appendage occlusion,” Dr. O’Neill said in an interview. “This particular study may serve as a guide to an adequately powered randomized trial of CT versus TEE in left atrial appendage occlusion.” Future LAAC trials should incorporate preprocedural CCTA.

Dr. O’Neill noted that, as a subanalysis of a randomized trial, the “results are hypothesis generating.” However, he added, “the results are in line with several previous studies of CT versus TEE in left atrial appendage occlusion.”

Dr Räber disclosed financial relationships with Abbott Vascular, Boston Scientific, Biotronik, Infraredx, Heartflow, Sanofi, Regeneron, Amgen, AstraZeneca, CSL Behring, Canon, Occlutech, and Vifor. Dr. O’Neill disclosed financial relationships with Edwards Lifesciences, Medtronic, and Abbott Vascular.