Long-Term Survival After Alcohol Septal Ablation For Hypertrophic Obstructive Cardiomyopathy: A 16-Year Experience

Background. Alcohol septal ablation (ASA) is an accepted treatment for medically refractory hypertrophic obstructive cardiomyopathy (HOCM). The procedural and medium-term outcomes have been reassuring. The iatrogenic targeted septal infarction has raised theoretical concerns about risk of arrhythmia and long-term survival. In this study, we describe the long-term survival in a large cohort of patients from a single referral center and the iterative improvement in procedural technique since its inception. Methods. This cohort includes 580 consecutive patients who underwent 664 ASA procedures between the years 1999 and 2015. Procedural details and outcomes are described. Long-term survival is compared with expected survival of demographically similar controls. Results. Fifty-four percent were women and 85% were Caucasian. At the time of ablation, mean age was 57 +/- 15 years, septal thickness was 2.1 +/- 0.5 cm, and left ventricular outflow tract (LVOT) gradient was 72 +/- 40 mm Hg at rest and 102 +/- 58 mm Hg with Valsalva provocation. Mean follow-up was 8.0 +/- 4.3 years. LVOT gradient reduction >50% was achieved in 94% of patients with reduction in New York Heart Association functional class scores and increase in exercise treadmill duration. Procedural mortality was 0.9%. Over the 16-year period, survival estimates at 1, 5, 10, and 15 years were 98%, 92%, 84%, and 81%, respectively, which are comparable to demographically similar controls. The standardized mortality ratio was 0.84 (95% confidence interval, 0.66-1.06); P=.09. Conclusions. ASA appears to be a safe and effective treatment for symptomatic HOCM refractory to medical therapy with long-term survival comparable to a demographically similar United States population.