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BOSTON – Results from the CABANA trial, the long-awaited, head-to-head comparison of percutaneous catheter ablation with drug therapy for the treatment of atrial fibrillation by restoring sinus rhythm, failed to accomplish what it was designed to prove.
That is, that catheter ablation was superior to medical management for a combined endpoint of all-cause death, stroke, serious bleeding, or cardiac arrest.
But by showing in a major trial with more than 2,200 randomized patients that catheter ablation was no worse than drugs for this combined endpoint, or for the solitary endpoint of all-cause mortality, the results seemed to establish first-line catheter ablation as at least a viable alternative to upfront antiarrhythmic drug management that some patients might find attractive, especially because the results also confirmed ablation as superior to medical treatment as a more definitive treatment of atrial fibrillation by cutting the rate of recurrent arrhythmia nearly in half.
The trial results also gave proponents of catheter ablation some tantalizing hints that this approach actually may have been superior to antiarrhythmic drugs, if only the randomization assignments had been more closely followed as the trial proceeded. But that didn’t happen, with about 30% of patients assigned to medical management crossing over to undergo catheter ablation, presumably because they had received inadequate symptom relief from their drug regimens. In addition, 10% of patients assigned to catheter ablation didn’t undergo it, primarily because they reconsidered after randomization and decided to not choose the invasive option. These crossovers produced a disparity in the outcomes between the standard, intention-to-treat analysis, which showed a neutral difference between the two study arms, and the per-protocol analysis that censored out crossover patients. The per-protocol analysis showed a statistically significant, 27% relative risk reduction in the primary endpoint among the patients randomized to and actually treated with catheter ablation, compared with those randomized to and exclusively treated medically.
“A patient can’t receive benefit from ablation if you don’t ablate,” noted the study’s lead investigation, Douglas L. Packer, MD, as he reported the results at the annual scientific sessions of the Heart Rhythm Society. “When you have this many crossovers and so many patients not getting their assigned treatments, then an on-treatment analysis is required, said Dr. Packer, a cardiac electrophysiologist and professor of medicine at the Mayo Clinic in Rochester, Minn.
The prespecified on-treatment analysis, which, instead of censoring crossover patients, analyzed outcomes based on the treatments that patients actually received, showed a statistically significant one-third reduction in the primary endpoint among the ablated patients and a statistically significant 40% relative reduction in all-cause mortality in the ablated arm, compared with those on medical management.
“For symptomatic treatment, and to restore and maintain sinus rhythm, there is no question that ablation is better. We knew that before this trial, and we know it even more convincingly now,” commented Jeremy N. Ruskin, MD, professor of medicine at Harvard Medical School and director of the cardiac arrhythmia service at Massachusetts General Hospital, both in Boston. “To a large extent, we do ablations for symptomatic benefit; to get patients feeling better. And I think this trial will confirm that because this will likely follow the better reduction in atrial fibrillation burden, which was quite impressive in the study.” Dr. Packer said that the quality of life data collected in CABANA will come out in a report later in 2018.
The dilemma that Dr. Ruskin and other physicians who heard the results voiced was how best to interpret the study’s primary results.
“This trial was designed to address whether ablation has an impact [compared with medical management] on hard endpoints, like mortality, and the intention-to-treat analysis showed no difference. I feel bound to adhere to the intention-to-treat analysis, the primary result” the traditional default arbiter of a randomized trial’s outcome, Dr. Ruskin said in an interview, “But intention-to-treat analyses are built on a foundation where most patients are maintained on their assigned treatment.”
“As a practicing physician, I’ll look at the on-treatment analysis because those are the patients who actually got the treatment,” commented Christine M. Albert, MD, professor of medicine at Harvard and director of the Center for Arrhythmia Prevention at Brigham and Women’s Hospital, Boston. She also highlighted a clear message from the trial about ablation.
The results “tell us that there wasn’t harm from ablation,” Dr. Albert said during a press conference. “That is really important because, before this, we didn’t know for sure. These data make me a little more confident about offering patients ablation. I now have data to discuss with patients that’s useful for decision making.”
“There was certainly no signal whatsoever of harm by taking patients to ablation early” in their management, agreed Dr. Ruskin. “I find that very reassuring and encouraging.”
CABANA (Catheter Ablation vs. Antiarrhythmic Drug Therapy for Atrial Fibrillation Trial) started in 2009 and enrolled 2,204 patients with documented, new-onset paroxysmal or persistent atrial fibrillation (AF) at 110 centers in 10 countries. Patients averaged about 68 years of age, with about 15% at least 75 years old, and in general were what Dr. Packer characterized as a high-risk group, with a high prevalence of comorbidities: 23% with sleep apnea, 10% with cardiomyopathy, 15% with heart failure, 10% with a prior stroke or transient ischemic attack, and just over a third in a New York Heart Association functional class II or III. About 43% had paroxysmal AF, about 47% had persistent AF, and the remaining patients had long-standing persistent AF. The median duration of AF at the time of entry was just over 1 year.
The clinicians treating the patients assigned to medical management could decide on a case-by-case basis whether to use rate or rhythm control, and about 12% of patients received rate control. The trial design specified pulmonary-vein isolation as the method for left atrial ablation.
In the intention-to-treat analyses, ablation was linked to a 14% relative reduction in the composite primary endpoint, a nonsignificant difference. All-cause mortality was a relative 15% lower in the ablation arm, also not statistically significant. A third prespecified, secondary endpoint, all-cause mortality plus cardiovascular hospitalization, was 17% lower in the ablated patients than in those on drug treatment in the intention-to-treat analysis, a statistically significant difference (P = .002).
The adverse event rate in the ablation arm was “surprisingly” low, said Dr. Packer, with a 3.9% rate of complications from catheter insertion (more than half were hematomas), a 3.4% rate of complications from catheter manipulation within the heart (2.2% involved pericardial effusions that required no intervention), and a 1.8% rate of ablation-related events, most commonly severe pericardial chest pain. “The risks of ablation seem to be lower than we thought,” he said, but quickly added the caveat that all ablation operators in CABANA had to have performed at least 100 ablation cases prior to the trial. The observed safety applies to operators “who know what they’re doing,” he said. Adverse events in the medically treated patients were typical for patients treated with amiodarone, Dr. Packer said, with the most common events hyper- or hypothyroidism, in 1.6%, and an allergic reaction, in 0.6%. In the intention-to-treat analysis the incidence of recurrent AF following a 90-day blanking period after ablation was 47% lower in the ablated patients relative to the drug-treated patients (P less than .0001).
Dr. Packer also presented an intriguing subgroup analysis for the primary endpoint that showed ablation had the best performance relative to medical management in patients younger than 65 years, patients with a history of heart failure, minority patients, and those who entered the trial in NYHA functional class II or III. The subgroup analysis showed a signal for worse performance from ablation in patients who were at least 75 years old. “I’m concerned about these older patients; we need to look into this,” Dr. Packer said. He also expressed optimism that the good performance of ablation in heart failure patients, while an exploratory finding, suggested confirmation of the results reported recently from the CASTLE-AF trial, which also showed good outcomes from catheter ablation for treating patients with heart failure and AF (N Engl J Med. 2018 Feb 1;378[5]:417-27).
The main qualification Dr. Packer voiced about the CABANA results is that not every AF patient should get ablation. “All treatments are not right for all patients. Not everyone with AF needs ablation. You need to talk with patients about it.” But despite this caution, he declared that the results had already changed his practice.
“I much less often now say to patients ‘let’s go with a drug and see what happens.’ I’d still do that if I wasn’t sure that a patient’s symptoms were caused by their AF” as opposed to their underlying heart disease, but if I’m pretty certain that their symptoms are caused by their AF over the past few months, I’ve become more likely to say that front-line ablation is reasonable,” Dr. Packer said.
CABANA received partial funding from Biosense Webster, Boston Scientific, Medtronic, and St. Jude. Dr. Packer has been a consultant to and has received research funding from all four of these companies and also from several other companies. Dr. Ruskin has been a consultant to Biosense Webster and Medtronic and several other companies, has an ownership interest in Amgen, Cameron Health, InfoBionic, Newpace, Portola, and Regeneron, and has a fiduciary role in Pharmaco-Kinesis. Dr. Albert has been a consultant to Myokardia and Sanofi Aventis and has received research funding from Roche Diagnostics and St. Jude.
SOURCE: Packer DL et al. HRS 2018, Abstract B-LBCT01-05.
The data from CABANA suggest that at the least, catheter ablation is the equivalent of drug therapy, and I think in many cases, it is probably superior. Patients with atrial fibrillation should be allowed to undergo ablation as their first treatment, performed by operators who know what they’re doing. These are excellent results, but they do not apply to every patient with atrial fibrillation; they apply to patients like those enrolled in the trial.
Some people will look at the results from the intention-to-treat analysis of the primary endpoint and say that this is a neutral result. The patients who I treat often ask me “if I get this treatment, what will likely happen to me.” They are not interested in what happened to patients in a trial who never received the treatment they were supposed to get. I recommend that people interested in CABANA, look at the full data set and do not limit themselves to a knee-jerk reaction to the intention-to-treat analysis.
The results also speak very loudly about the importance of sinus rhythm in patients with heart failure. The results in the subgroup of patients with heart failure appear to support the findings from CASTLE-AF (N Engl J Med. 2018 Feb 1;378[5]:417-27).
Eric N. Prystowsky, MD , is a cardiac electrophysiologist with the St. Vincent Medical Group in Indianapolis. He has been a consultant to CardioNet and Medtronic, has an equity interest in Stereotaxis, and receives fellowship support from Medtronic and St. Jude. He made these comments as designated discussant for CABANA.
The data from CABANA suggest that at the least, catheter ablation is the equivalent of drug therapy, and I think in many cases, it is probably superior. Patients with atrial fibrillation should be allowed to undergo ablation as their first treatment, performed by operators who know what they’re doing. These are excellent results, but they do not apply to every patient with atrial fibrillation; they apply to patients like those enrolled in the trial.
Some people will look at the results from the intention-to-treat analysis of the primary endpoint and say that this is a neutral result. The patients who I treat often ask me “if I get this treatment, what will likely happen to me.” They are not interested in what happened to patients in a trial who never received the treatment they were supposed to get. I recommend that people interested in CABANA, look at the full data set and do not limit themselves to a knee-jerk reaction to the intention-to-treat analysis.
The results also speak very loudly about the importance of sinus rhythm in patients with heart failure. The results in the subgroup of patients with heart failure appear to support the findings from CASTLE-AF (N Engl J Med. 2018 Feb 1;378[5]:417-27).
Eric N. Prystowsky, MD , is a cardiac electrophysiologist with the St. Vincent Medical Group in Indianapolis. He has been a consultant to CardioNet and Medtronic, has an equity interest in Stereotaxis, and receives fellowship support from Medtronic and St. Jude. He made these comments as designated discussant for CABANA.
The data from CABANA suggest that at the least, catheter ablation is the equivalent of drug therapy, and I think in many cases, it is probably superior. Patients with atrial fibrillation should be allowed to undergo ablation as their first treatment, performed by operators who know what they’re doing. These are excellent results, but they do not apply to every patient with atrial fibrillation; they apply to patients like those enrolled in the trial.
Some people will look at the results from the intention-to-treat analysis of the primary endpoint and say that this is a neutral result. The patients who I treat often ask me “if I get this treatment, what will likely happen to me.” They are not interested in what happened to patients in a trial who never received the treatment they were supposed to get. I recommend that people interested in CABANA, look at the full data set and do not limit themselves to a knee-jerk reaction to the intention-to-treat analysis.
The results also speak very loudly about the importance of sinus rhythm in patients with heart failure. The results in the subgroup of patients with heart failure appear to support the findings from CASTLE-AF (N Engl J Med. 2018 Feb 1;378[5]:417-27).
Eric N. Prystowsky, MD , is a cardiac electrophysiologist with the St. Vincent Medical Group in Indianapolis. He has been a consultant to CardioNet and Medtronic, has an equity interest in Stereotaxis, and receives fellowship support from Medtronic and St. Jude. He made these comments as designated discussant for CABANA.
BOSTON – Results from the CABANA trial, the long-awaited, head-to-head comparison of percutaneous catheter ablation with drug therapy for the treatment of atrial fibrillation by restoring sinus rhythm, failed to accomplish what it was designed to prove.
That is, that catheter ablation was superior to medical management for a combined endpoint of all-cause death, stroke, serious bleeding, or cardiac arrest.
But by showing in a major trial with more than 2,200 randomized patients that catheter ablation was no worse than drugs for this combined endpoint, or for the solitary endpoint of all-cause mortality, the results seemed to establish first-line catheter ablation as at least a viable alternative to upfront antiarrhythmic drug management that some patients might find attractive, especially because the results also confirmed ablation as superior to medical treatment as a more definitive treatment of atrial fibrillation by cutting the rate of recurrent arrhythmia nearly in half.
The trial results also gave proponents of catheter ablation some tantalizing hints that this approach actually may have been superior to antiarrhythmic drugs, if only the randomization assignments had been more closely followed as the trial proceeded. But that didn’t happen, with about 30% of patients assigned to medical management crossing over to undergo catheter ablation, presumably because they had received inadequate symptom relief from their drug regimens. In addition, 10% of patients assigned to catheter ablation didn’t undergo it, primarily because they reconsidered after randomization and decided to not choose the invasive option. These crossovers produced a disparity in the outcomes between the standard, intention-to-treat analysis, which showed a neutral difference between the two study arms, and the per-protocol analysis that censored out crossover patients. The per-protocol analysis showed a statistically significant, 27% relative risk reduction in the primary endpoint among the patients randomized to and actually treated with catheter ablation, compared with those randomized to and exclusively treated medically.
“A patient can’t receive benefit from ablation if you don’t ablate,” noted the study’s lead investigation, Douglas L. Packer, MD, as he reported the results at the annual scientific sessions of the Heart Rhythm Society. “When you have this many crossovers and so many patients not getting their assigned treatments, then an on-treatment analysis is required, said Dr. Packer, a cardiac electrophysiologist and professor of medicine at the Mayo Clinic in Rochester, Minn.
The prespecified on-treatment analysis, which, instead of censoring crossover patients, analyzed outcomes based on the treatments that patients actually received, showed a statistically significant one-third reduction in the primary endpoint among the ablated patients and a statistically significant 40% relative reduction in all-cause mortality in the ablated arm, compared with those on medical management.
“For symptomatic treatment, and to restore and maintain sinus rhythm, there is no question that ablation is better. We knew that before this trial, and we know it even more convincingly now,” commented Jeremy N. Ruskin, MD, professor of medicine at Harvard Medical School and director of the cardiac arrhythmia service at Massachusetts General Hospital, both in Boston. “To a large extent, we do ablations for symptomatic benefit; to get patients feeling better. And I think this trial will confirm that because this will likely follow the better reduction in atrial fibrillation burden, which was quite impressive in the study.” Dr. Packer said that the quality of life data collected in CABANA will come out in a report later in 2018.
The dilemma that Dr. Ruskin and other physicians who heard the results voiced was how best to interpret the study’s primary results.
“This trial was designed to address whether ablation has an impact [compared with medical management] on hard endpoints, like mortality, and the intention-to-treat analysis showed no difference. I feel bound to adhere to the intention-to-treat analysis, the primary result” the traditional default arbiter of a randomized trial’s outcome, Dr. Ruskin said in an interview, “But intention-to-treat analyses are built on a foundation where most patients are maintained on their assigned treatment.”
“As a practicing physician, I’ll look at the on-treatment analysis because those are the patients who actually got the treatment,” commented Christine M. Albert, MD, professor of medicine at Harvard and director of the Center for Arrhythmia Prevention at Brigham and Women’s Hospital, Boston. She also highlighted a clear message from the trial about ablation.
The results “tell us that there wasn’t harm from ablation,” Dr. Albert said during a press conference. “That is really important because, before this, we didn’t know for sure. These data make me a little more confident about offering patients ablation. I now have data to discuss with patients that’s useful for decision making.”
“There was certainly no signal whatsoever of harm by taking patients to ablation early” in their management, agreed Dr. Ruskin. “I find that very reassuring and encouraging.”
CABANA (Catheter Ablation vs. Antiarrhythmic Drug Therapy for Atrial Fibrillation Trial) started in 2009 and enrolled 2,204 patients with documented, new-onset paroxysmal or persistent atrial fibrillation (AF) at 110 centers in 10 countries. Patients averaged about 68 years of age, with about 15% at least 75 years old, and in general were what Dr. Packer characterized as a high-risk group, with a high prevalence of comorbidities: 23% with sleep apnea, 10% with cardiomyopathy, 15% with heart failure, 10% with a prior stroke or transient ischemic attack, and just over a third in a New York Heart Association functional class II or III. About 43% had paroxysmal AF, about 47% had persistent AF, and the remaining patients had long-standing persistent AF. The median duration of AF at the time of entry was just over 1 year.
The clinicians treating the patients assigned to medical management could decide on a case-by-case basis whether to use rate or rhythm control, and about 12% of patients received rate control. The trial design specified pulmonary-vein isolation as the method for left atrial ablation.
In the intention-to-treat analyses, ablation was linked to a 14% relative reduction in the composite primary endpoint, a nonsignificant difference. All-cause mortality was a relative 15% lower in the ablation arm, also not statistically significant. A third prespecified, secondary endpoint, all-cause mortality plus cardiovascular hospitalization, was 17% lower in the ablated patients than in those on drug treatment in the intention-to-treat analysis, a statistically significant difference (P = .002).
The adverse event rate in the ablation arm was “surprisingly” low, said Dr. Packer, with a 3.9% rate of complications from catheter insertion (more than half were hematomas), a 3.4% rate of complications from catheter manipulation within the heart (2.2% involved pericardial effusions that required no intervention), and a 1.8% rate of ablation-related events, most commonly severe pericardial chest pain. “The risks of ablation seem to be lower than we thought,” he said, but quickly added the caveat that all ablation operators in CABANA had to have performed at least 100 ablation cases prior to the trial. The observed safety applies to operators “who know what they’re doing,” he said. Adverse events in the medically treated patients were typical for patients treated with amiodarone, Dr. Packer said, with the most common events hyper- or hypothyroidism, in 1.6%, and an allergic reaction, in 0.6%. In the intention-to-treat analysis the incidence of recurrent AF following a 90-day blanking period after ablation was 47% lower in the ablated patients relative to the drug-treated patients (P less than .0001).
Dr. Packer also presented an intriguing subgroup analysis for the primary endpoint that showed ablation had the best performance relative to medical management in patients younger than 65 years, patients with a history of heart failure, minority patients, and those who entered the trial in NYHA functional class II or III. The subgroup analysis showed a signal for worse performance from ablation in patients who were at least 75 years old. “I’m concerned about these older patients; we need to look into this,” Dr. Packer said. He also expressed optimism that the good performance of ablation in heart failure patients, while an exploratory finding, suggested confirmation of the results reported recently from the CASTLE-AF trial, which also showed good outcomes from catheter ablation for treating patients with heart failure and AF (N Engl J Med. 2018 Feb 1;378[5]:417-27).
The main qualification Dr. Packer voiced about the CABANA results is that not every AF patient should get ablation. “All treatments are not right for all patients. Not everyone with AF needs ablation. You need to talk with patients about it.” But despite this caution, he declared that the results had already changed his practice.
“I much less often now say to patients ‘let’s go with a drug and see what happens.’ I’d still do that if I wasn’t sure that a patient’s symptoms were caused by their AF” as opposed to their underlying heart disease, but if I’m pretty certain that their symptoms are caused by their AF over the past few months, I’ve become more likely to say that front-line ablation is reasonable,” Dr. Packer said.
CABANA received partial funding from Biosense Webster, Boston Scientific, Medtronic, and St. Jude. Dr. Packer has been a consultant to and has received research funding from all four of these companies and also from several other companies. Dr. Ruskin has been a consultant to Biosense Webster and Medtronic and several other companies, has an ownership interest in Amgen, Cameron Health, InfoBionic, Newpace, Portola, and Regeneron, and has a fiduciary role in Pharmaco-Kinesis. Dr. Albert has been a consultant to Myokardia and Sanofi Aventis and has received research funding from Roche Diagnostics and St. Jude.
SOURCE: Packer DL et al. HRS 2018, Abstract B-LBCT01-05.
BOSTON – Results from the CABANA trial, the long-awaited, head-to-head comparison of percutaneous catheter ablation with drug therapy for the treatment of atrial fibrillation by restoring sinus rhythm, failed to accomplish what it was designed to prove.
That is, that catheter ablation was superior to medical management for a combined endpoint of all-cause death, stroke, serious bleeding, or cardiac arrest.
But by showing in a major trial with more than 2,200 randomized patients that catheter ablation was no worse than drugs for this combined endpoint, or for the solitary endpoint of all-cause mortality, the results seemed to establish first-line catheter ablation as at least a viable alternative to upfront antiarrhythmic drug management that some patients might find attractive, especially because the results also confirmed ablation as superior to medical treatment as a more definitive treatment of atrial fibrillation by cutting the rate of recurrent arrhythmia nearly in half.
The trial results also gave proponents of catheter ablation some tantalizing hints that this approach actually may have been superior to antiarrhythmic drugs, if only the randomization assignments had been more closely followed as the trial proceeded. But that didn’t happen, with about 30% of patients assigned to medical management crossing over to undergo catheter ablation, presumably because they had received inadequate symptom relief from their drug regimens. In addition, 10% of patients assigned to catheter ablation didn’t undergo it, primarily because they reconsidered after randomization and decided to not choose the invasive option. These crossovers produced a disparity in the outcomes between the standard, intention-to-treat analysis, which showed a neutral difference between the two study arms, and the per-protocol analysis that censored out crossover patients. The per-protocol analysis showed a statistically significant, 27% relative risk reduction in the primary endpoint among the patients randomized to and actually treated with catheter ablation, compared with those randomized to and exclusively treated medically.
“A patient can’t receive benefit from ablation if you don’t ablate,” noted the study’s lead investigation, Douglas L. Packer, MD, as he reported the results at the annual scientific sessions of the Heart Rhythm Society. “When you have this many crossovers and so many patients not getting their assigned treatments, then an on-treatment analysis is required, said Dr. Packer, a cardiac electrophysiologist and professor of medicine at the Mayo Clinic in Rochester, Minn.
The prespecified on-treatment analysis, which, instead of censoring crossover patients, analyzed outcomes based on the treatments that patients actually received, showed a statistically significant one-third reduction in the primary endpoint among the ablated patients and a statistically significant 40% relative reduction in all-cause mortality in the ablated arm, compared with those on medical management.
“For symptomatic treatment, and to restore and maintain sinus rhythm, there is no question that ablation is better. We knew that before this trial, and we know it even more convincingly now,” commented Jeremy N. Ruskin, MD, professor of medicine at Harvard Medical School and director of the cardiac arrhythmia service at Massachusetts General Hospital, both in Boston. “To a large extent, we do ablations for symptomatic benefit; to get patients feeling better. And I think this trial will confirm that because this will likely follow the better reduction in atrial fibrillation burden, which was quite impressive in the study.” Dr. Packer said that the quality of life data collected in CABANA will come out in a report later in 2018.
The dilemma that Dr. Ruskin and other physicians who heard the results voiced was how best to interpret the study’s primary results.
“This trial was designed to address whether ablation has an impact [compared with medical management] on hard endpoints, like mortality, and the intention-to-treat analysis showed no difference. I feel bound to adhere to the intention-to-treat analysis, the primary result” the traditional default arbiter of a randomized trial’s outcome, Dr. Ruskin said in an interview, “But intention-to-treat analyses are built on a foundation where most patients are maintained on their assigned treatment.”
“As a practicing physician, I’ll look at the on-treatment analysis because those are the patients who actually got the treatment,” commented Christine M. Albert, MD, professor of medicine at Harvard and director of the Center for Arrhythmia Prevention at Brigham and Women’s Hospital, Boston. She also highlighted a clear message from the trial about ablation.
The results “tell us that there wasn’t harm from ablation,” Dr. Albert said during a press conference. “That is really important because, before this, we didn’t know for sure. These data make me a little more confident about offering patients ablation. I now have data to discuss with patients that’s useful for decision making.”
“There was certainly no signal whatsoever of harm by taking patients to ablation early” in their management, agreed Dr. Ruskin. “I find that very reassuring and encouraging.”
CABANA (Catheter Ablation vs. Antiarrhythmic Drug Therapy for Atrial Fibrillation Trial) started in 2009 and enrolled 2,204 patients with documented, new-onset paroxysmal or persistent atrial fibrillation (AF) at 110 centers in 10 countries. Patients averaged about 68 years of age, with about 15% at least 75 years old, and in general were what Dr. Packer characterized as a high-risk group, with a high prevalence of comorbidities: 23% with sleep apnea, 10% with cardiomyopathy, 15% with heart failure, 10% with a prior stroke or transient ischemic attack, and just over a third in a New York Heart Association functional class II or III. About 43% had paroxysmal AF, about 47% had persistent AF, and the remaining patients had long-standing persistent AF. The median duration of AF at the time of entry was just over 1 year.
The clinicians treating the patients assigned to medical management could decide on a case-by-case basis whether to use rate or rhythm control, and about 12% of patients received rate control. The trial design specified pulmonary-vein isolation as the method for left atrial ablation.
In the intention-to-treat analyses, ablation was linked to a 14% relative reduction in the composite primary endpoint, a nonsignificant difference. All-cause mortality was a relative 15% lower in the ablation arm, also not statistically significant. A third prespecified, secondary endpoint, all-cause mortality plus cardiovascular hospitalization, was 17% lower in the ablated patients than in those on drug treatment in the intention-to-treat analysis, a statistically significant difference (P = .002).
The adverse event rate in the ablation arm was “surprisingly” low, said Dr. Packer, with a 3.9% rate of complications from catheter insertion (more than half were hematomas), a 3.4% rate of complications from catheter manipulation within the heart (2.2% involved pericardial effusions that required no intervention), and a 1.8% rate of ablation-related events, most commonly severe pericardial chest pain. “The risks of ablation seem to be lower than we thought,” he said, but quickly added the caveat that all ablation operators in CABANA had to have performed at least 100 ablation cases prior to the trial. The observed safety applies to operators “who know what they’re doing,” he said. Adverse events in the medically treated patients were typical for patients treated with amiodarone, Dr. Packer said, with the most common events hyper- or hypothyroidism, in 1.6%, and an allergic reaction, in 0.6%. In the intention-to-treat analysis the incidence of recurrent AF following a 90-day blanking period after ablation was 47% lower in the ablated patients relative to the drug-treated patients (P less than .0001).
Dr. Packer also presented an intriguing subgroup analysis for the primary endpoint that showed ablation had the best performance relative to medical management in patients younger than 65 years, patients with a history of heart failure, minority patients, and those who entered the trial in NYHA functional class II or III. The subgroup analysis showed a signal for worse performance from ablation in patients who were at least 75 years old. “I’m concerned about these older patients; we need to look into this,” Dr. Packer said. He also expressed optimism that the good performance of ablation in heart failure patients, while an exploratory finding, suggested confirmation of the results reported recently from the CASTLE-AF trial, which also showed good outcomes from catheter ablation for treating patients with heart failure and AF (N Engl J Med. 2018 Feb 1;378[5]:417-27).
The main qualification Dr. Packer voiced about the CABANA results is that not every AF patient should get ablation. “All treatments are not right for all patients. Not everyone with AF needs ablation. You need to talk with patients about it.” But despite this caution, he declared that the results had already changed his practice.
“I much less often now say to patients ‘let’s go with a drug and see what happens.’ I’d still do that if I wasn’t sure that a patient’s symptoms were caused by their AF” as opposed to their underlying heart disease, but if I’m pretty certain that their symptoms are caused by their AF over the past few months, I’ve become more likely to say that front-line ablation is reasonable,” Dr. Packer said.
CABANA received partial funding from Biosense Webster, Boston Scientific, Medtronic, and St. Jude. Dr. Packer has been a consultant to and has received research funding from all four of these companies and also from several other companies. Dr. Ruskin has been a consultant to Biosense Webster and Medtronic and several other companies, has an ownership interest in Amgen, Cameron Health, InfoBionic, Newpace, Portola, and Regeneron, and has a fiduciary role in Pharmaco-Kinesis. Dr. Albert has been a consultant to Myokardia and Sanofi Aventis and has received research funding from Roche Diagnostics and St. Jude.
SOURCE: Packer DL et al. HRS 2018, Abstract B-LBCT01-05.
REPORTING FROM HEART RHYTHM 2018
Key clinical point: Catheter atrial fib ablation showed no significant benefit over medical management for the CABANA’s primary endpoint.
Major finding: The composite endpoint that included all-cause death was a nonsignificant 14% lower with ablation than with medical management in the intention-to-treat analysis.
Study details: CABANA, a multicenter, randomized trial with 2,204 patients.
Disclosures: CABANA received partial funding from Biosense Webster, Boston Scientific, Medtronic, and St. Jude. Dr. Packer has been a consultant to and has received research funding from all four of these companies and from several other companies. Dr. Ruskin has been a consultant to Biosense Webster and Medtronic and several other companies, has an ownership interest in Amgen, Cameron Health, InfoBionic, Newpace, Portola, and Regeneron, and has a fiduciary role in Pharmaco-Kinesis. Dr. Albert has been a consultant to Myokardia and Sanofi-Aventis and has received research funding from Roche Diagnostics and St. Jude.
Source: Packer D et al. HRS 2018, Abstract B-LBCT01-05.