Long-term clinical outcomes after alcohol septal ablation for hypertrophic obstructive cardiomyopathy in Japan: a retrospective study

Hypertrophic cardiomyopathy is characterized by significant left ventricular wall thickening, often leading to obstructive symptoms. Alcohol septal ablation (ASA) has emerged as an effective treatment for patients with hypertrophic obstructive cardiomyopathy (HOCM) who remain symptomatic despite maximal medical therapy. However, the detailed long-term effects of ASA in Japanese patients with HOCM remain unclear. Therefore, this study aimed to investigate the long-term effects of ASA for HOCM by evaluating changes in symptoms, pressure gradient, hemodynamics, prognosis, and predictive factors for cardiovascular events over time. In this retrospective study, we examined 239 highly symptomatic patients (age, 64 ± 13 years; median follow-up, 6.9 years) treated with ASA for drug-refractory HOCM between 1998 and 2021. Patients were assessed using transthoracic echocardiography, magnetic resonance imaging, and cardiac catheterization. Follow-up evaluations included clinical assessments, electrocardiography, and echocardiography. Data analysis included descriptive statistics, Kaplan–Meier analysis, and multivariate regression. ASA reduced the left ventricular outflow tract gradient from 90.5 ± 52.8 to 14.4 ± 17.1 mmHg (P < 0.01) and New York Heart Association (NYHA) class from 3 [2.5–3] to 1 [1–2] at 10 years after ASA (P < 0.01). The 30-day mortality rate following ASA was 1%. Overall, 31 patients (13%) died during the follow-up period. The survival rates at 1, 5, 10, and 15 years after ASA were 97.4%, 89.9%, 83.7%, and 77.6%, respectively. Multivariable analysis revealed NYHA functional class before ASA (odds ratio [OR], 3.09; 95% confidence interval [CI], 1.40–6.82; P = 0.005), beta-blocker use (OR, 0.25; 95% CI, 0.07–0.91; P = 0.036), and class Ia agent use (OR, 0.31; 95% CI, 0.13–0.75; P = 0.009) as independent predictors of all-cause mortality. This study demonstrated low periprocedural and long-term mortality rates following ASA in patients with HOCM, suggesting that ASA provides durable symptomatic relief and reduces left ventricular outflow tract obstruction in selected highly symptomatic patients with HOCM.