SNOWMASS, COLO. – Recent data on long-term outcomes of alcohol septal ablation for hypertrophic obstructive cardiomyopathy are “quite favorable” and will be considered in the deliberations of the task force charged with revising the 2011 American College of Cardiology/American Heart Association guidelines.
, a member of the task force and director of the Center of Valve and Structural Heart Disease at the Minneapolis Heart Institute, explained that the 2011 ACC/AHA guidelines on hypertrophic cardiomyopathy took an appropriately cautious stance regarding alcohol septal ablation (ASA) in light of a 2010 Dutch report warning of an increased risk of sudden cardiac death following the procedure ( ) and a dearth of evidence to the contrary.
The 2011 guidelines recommend surgical myectomy performed in an experienced center as the class I treatment of choice for patients with severely symptomatic, drug-refractory hypertrophic obstructive cardiomyopathy (HOCM). ASA gets a class IIa recommendation for patients at high surgical risk, and is class III – meaning don’t do it – for patients under age 40 years if myectomy is a viable option (), Dr. Sorajja noted at the Annual Cardiovascular Conference at Snowmass sponsored by the American College of Cardiology.
However, the cautionary Dutch study that influenced the 2011 guidelines is considered controversial, he explained. It was small – just 91 patients – and the operators used twice the normal volume of alcohol, with a resultant much larger, potentially arrhythmogenic myocardial ablation scar. So, many experts have been eagerly awaiting additional long-term studies. And that long-sought data has recently been piling up. Since the 2011 guidelines, six long-term studies have been published, including one led by Dr. Sorajja (). The results have been consistently favorable, with 5-year survival rates of 87%-96%, in line with rates in the general population.
The largest of these studies included 1,197 patients who underwent ASA at seven centers in four European countries. The 30-day mortality and pacemaker implantation rates were significantly lower in patients aged up to 50 years, compared with those aged 65 and up. The annual mortality rate during a mean follow-up of 5.4 years was 1% in patients age 50 years and younger, 2.1% in those aged 51-64, and 5.1% in the oldest group. Arrhythmic events occurred at a rate of about 1% per year in all three age groups. And 95% of patients in the youngest group were in New York Heart Association class I or II at last follow-up ().
In an accompanying editorial,, of Massachusetts General Hospital, Boston, commented that “high-volume surgical myectomy centers are few and far between” and there is “a clear inverse relation between [surgical] procedure volume and outcomes.”
The study “provides the most robust data to date regarding the outcomes of ASA in younger patients, precisely the type of data that were missing at the time of writing of the ACCF/AHA and European Society of Cardiology guidelines. Given the favorable outcomes of ASA in this age group, and the unavailability of high-volume myectomy programs in many geographic regions, the time has come to liberalize the indication for ASA in younger patients,” declared Dr. Fifer ().