Patient Selection for Septal Ablation in HOCM Refined

NEW YORK – Preliminary data from the Mayo Clinic may provide insight into differentiating patients with hypertrophic obstructive cardiomyopathy who would benefit most from either surgical septal myectomy or percutaneous septal ablation, according to an investigator’s report at the annual New York Cardiology Symposium.

Dr. Steve Ommen presented data showing that the percutaneous procedure had higher mortality and complication rates than did surgical myectomy, but noted that emerging data have identified patient characteristics that can guide a clinician’s choice of procedure. Either procedure can be indicated for a symptomatic patient with HOCM in whom drug treatment has failed. "If medications don’t work, if the patient’s quality of life is not satisfactory, that’s where we get into the controversy over whether or percutaneous alcohol ablation ought to be considered," he said.

Surgical myectomy has been considered the standard for HOCM treatment, but alcohol septal ablation has gained attention in recent years as a less-invasive approach. The determining factor for intervention is the left ventricular outflow tract (LVOT) pressure gradient, Dr. Ommen said: An LVOT gradient measure of 50 mm Hg or higher portends significant symptoms, but a measure of 30 mm Hg at rest in an otherwise symptomatic patient with a negative echocardiogram may require further testing. "You owe it to that patient to see if he or she can be easily provoked to a higher gradient on testing," he said.

Surgical myectomy has been shown to reduce the mortality rate in HOCM patients by half (from 2% to 1%), Dr. Ommen said. However, he noted that no randomized data have been published on outcomes of myectomy in HOCM. "These observational data show that overall survival in myectomy is similar to that of the general population," he said. "Survival is better than the historic population reports of HOCM, and arrhythmogenic death rates appear to be dramatically lower than other reports of patients with similar risk profiles."

On the other hand, published mortality rates in HOCM patients who had septal alcohol ablation have averaged 1.9% (range, 0%-4%), according to an analysis of 19 series that Dr. Ommen reported. The same analysis showed an overall complication rate of 20%. "The complication rates are largely driven by the need for a permanent pacemaker because of the complete cardioblock the ablation induced," he said.

The analysis also showed a technical success rate of 75% with septal alcohol ablation, he said. A separate study in which Dr. Ommen participated showed that HOCM patients younger than age 65 were more likely than myectomy patient to regress to New York Heart Association class III or IV symptoms within 4 years (JACC Cardiovasc. Interv. 2008;1:552-60) "On this basis, we generally prefer surgery for our younger patients," he said.

The Mayo analysis has provided clarity on who may succeed with septal alcohol ablation, according to Dr. Ommen. The patients who have the best success with ablation are over age 65 [and] have mild to moderate hypertrophy and a gradient that’s not severe," he said. HOCM patients with all three of those factors have a success rate of 90%; if they have just one of those factors, the success rate drops below 60%, he said.

"We can start to get our hands around patient selection for those who would succeed with the percutaneous procedure rather than the surgical procedure," he said.

He also cited two large 2008 studies that showed a long-term, annualized death rate of 1.5%-3% with percutaneous septal ablation. "These data would suggest that there may not be an increase in the death rate with ablation, but perhaps not the decrease that we saw with the surgical data," Dr. Ommen added.

He acknowledged the concern among some clinicians that septal ablation may raise the risk for arrhythmia in this patient population. "HOCM patients who have no risk for sudden cardiac death can still have a sudden cardiac death rate of 0.8% a year, but in patients who had ablation, about 2.8% had inappropriate implantable cardioverter defibrillator discharge," he said. "If they had one or more risk factors for sudden cardiac death, that then went to 13.4%, which is comparable to secondary prevention ICD discharge rates in the acute myocardial infarction CT from the National Registry of Myocardial Infarction."

Dr. Ommen had no relationships to disclose.

NEW YORK – Preliminary data from the Mayo Clinic may provide insight into differentiating patients with hypertrophic obstructive cardiomyopathy who would benefit most from either surgical septal myectomy or percutaneous septal ablation, according to an investigator’s report at the annual New York Cardiology Symposium.

Dr. Steve Ommen presented data showing that the percutaneous procedure had higher mortality and complication rates than did surgical myectomy, but noted that emerging data have identified patient characteristics that can guide a clinician’s choice of procedure. Either procedure can be indicated for a symptomatic patient with HOCM in whom drug treatment has failed. "If medications don’t work, if the patient’s quality of life is not satisfactory, that’s where we get into the controversy over whether or percutaneous alcohol ablation ought to be considered," he said.

Surgical myectomy has been considered the standard for HOCM treatment, but alcohol septal ablation has gained attention in recent years as a less-invasive approach. The determining factor for intervention is the left ventricular outflow tract (LVOT) pressure gradient, Dr. Ommen said: An LVOT gradient measure of 50 mm Hg or higher portends significant symptoms, but a measure of 30 mm Hg at rest in an otherwise symptomatic patient with a negative echocardiogram may require further testing. "You owe it to that patient to see if he or she can be easily provoked to a higher gradient on testing," he said.

Surgical myectomy has been shown to reduce the mortality rate in HOCM patients by half (from 2% to 1%), Dr. Ommen said. However, he noted that no randomized data have been published on outcomes of myectomy in HOCM. "These observational data show that overall survival in myectomy is similar to that of the general population," he said. "Survival is better than the historic population reports of HOCM, and arrhythmogenic death rates appear to be dramatically lower than other reports of patients with similar risk profiles."

On the other hand, published mortality rates in HOCM patients who had septal alcohol ablation have averaged 1.9% (range, 0%-4%), according to an analysis of 19 series that Dr. Ommen reported. The same analysis showed an overall complication rate of 20%. "The complication rates are largely driven by the need for a permanent pacemaker because of the complete cardioblock the ablation induced," he said.

The analysis also showed a technical success rate of 75% with septal alcohol ablation, he said. A separate study in which Dr. Ommen participated showed that HOCM patients younger than age 65 were more likely than myectomy patient to regress to New York Heart Association class III or IV symptoms within 4 years (JACC Cardiovasc. Interv. 2008;1:552-60) "On this basis, we generally prefer surgery for our younger patients," he said.

The Mayo analysis has provided clarity on who may succeed with septal alcohol ablation, according to Dr. Ommen. The patients who have the best success with ablation are over age 65 [and] have mild to moderate hypertrophy and a gradient that’s not severe," he said. HOCM patients with all three of those factors have a success rate of 90%; if they have just one of those factors, the success rate drops below 60%, he said.

"We can start to get our hands around patient selection for those who would succeed with the percutaneous procedure rather than the surgical procedure," he said.

He also cited two large 2008 studies that showed a long-term, annualized death rate of 1.5%-3% with percutaneous septal ablation. "These data would suggest that there may not be an increase in the death rate with ablation, but perhaps not the decrease that we saw with the surgical data," Dr. Ommen added.

He acknowledged the concern among some clinicians that septal ablation may raise the risk for arrhythmia in this patient population. "HOCM patients who have no risk for sudden cardiac death can still have a sudden cardiac death rate of 0.8% a year, but in patients who had ablation, about 2.8% had inappropriate implantable cardioverter defibrillator discharge," he said. "If they had one or more risk factors for sudden cardiac death, that then went to 13.4%, which is comparable to secondary prevention ICD discharge rates in the acute myocardial infarction CT from the National Registry of Myocardial Infarction."

Dr. Ommen had no relationships to disclose.

NEW YORK – Preliminary data from the Mayo Clinic may provide insight into differentiating patients with hypertrophic obstructive cardiomyopathy who would benefit most from either surgical septal myectomy or percutaneous septal ablation, according to an investigator’s report at the annual New York Cardiology Symposium.

Dr. Steve Ommen presented data showing that the percutaneous procedure had higher mortality and complication rates than did surgical myectomy, but noted that emerging data have identified patient characteristics that can guide a clinician’s choice of procedure. Either procedure can be indicated for a symptomatic patient with HOCM in whom drug treatment has failed. "If medications don’t work, if the patient’s quality of life is not satisfactory, that’s where we get into the controversy over whether or percutaneous alcohol ablation ought to be considered," he said.

Surgical myectomy has been considered the standard for HOCM treatment, but alcohol septal ablation has gained attention in recent years as a less-invasive approach. The determining factor for intervention is the left ventricular outflow tract (LVOT) pressure gradient, Dr. Ommen said: An LVOT gradient measure of 50 mm Hg or higher portends significant symptoms, but a measure of 30 mm Hg at rest in an otherwise symptomatic patient with a negative echocardiogram may require further testing. "You owe it to that patient to see if he or she can be easily provoked to a higher gradient on testing," he said.

Surgical myectomy has been shown to reduce the mortality rate in HOCM patients by half (from 2% to 1%), Dr. Ommen said. However, he noted that no randomized data have been published on outcomes of myectomy in HOCM. "These observational data show that overall survival in myectomy is similar to that of the general population," he said. "Survival is better than the historic population reports of HOCM, and arrhythmogenic death rates appear to be dramatically lower than other reports of patients with similar risk profiles."

On the other hand, published mortality rates in HOCM patients who had septal alcohol ablation have averaged 1.9% (range, 0%-4%), according to an analysis of 19 series that Dr. Ommen reported. The same analysis showed an overall complication rate of 20%. "The complication rates are largely driven by the need for a permanent pacemaker because of the complete cardioblock the ablation induced," he said.

The analysis also showed a technical success rate of 75% with septal alcohol ablation, he said. A separate study in which Dr. Ommen participated showed that HOCM patients younger than age 65 were more likely than myectomy patient to regress to New York Heart Association class III or IV symptoms within 4 years (JACC Cardiovasc. Interv. 2008;1:552-60) "On this basis, we generally prefer surgery for our younger patients," he said.

The Mayo analysis has provided clarity on who may succeed with septal alcohol ablation, according to Dr. Ommen. The patients who have the best success with ablation are over age 65 [and] have mild to moderate hypertrophy and a gradient that’s not severe," he said. HOCM patients with all three of those factors have a success rate of 90%; if they have just one of those factors, the success rate drops below 60%, he said.

"We can start to get our hands around patient selection for those who would succeed with the percutaneous procedure rather than the surgical procedure," he said.

He also cited two large 2008 studies that showed a long-term, annualized death rate of 1.5%-3% with percutaneous septal ablation. "These data would suggest that there may not be an increase in the death rate with ablation, but perhaps not the decrease that we saw with the surgical data," Dr. Ommen added.

He acknowledged the concern among some clinicians that septal ablation may raise the risk for arrhythmia in this patient population. "HOCM patients who have no risk for sudden cardiac death can still have a sudden cardiac death rate of 0.8% a year, but in patients who had ablation, about 2.8% had inappropriate implantable cardioverter defibrillator discharge," he said. "If they had one or more risk factors for sudden cardiac death, that then went to 13.4%, which is comparable to secondary prevention ICD discharge rates in the acute myocardial infarction CT from the National Registry of Myocardial Infarction."

Dr. Ommen had no relationships to disclose.