The long-term safety of alcohol septal ablation (ASA) to decrease the pressure gradient of the left ventricle (LV) in patients with hypertrophic cardiomyopathy has been questioned despite single-center trials and the establishment of national registries. Josef Veselka, MD, PhD, Charles University, Prague, Czech Republic, presented long-term clinical outcomes from the multinational Euro-ASA registry. The study end points were (1) survival and clinical outcome in patients treated with ASA; (2) predictors of mortality events and clinical outcome; and (3) relationships among the dose of alcohol injected during ASA, the improvement of LV outflow tract pressure gradient, and the occurrence of complete heart block.

The study population included 1275 consecutive patients treated with ASA at 10 centers in Europe. The mean age of the patients was 58 ± 14 years, and 49% were female. Patient characteristics at baseline and follow-up are presented in Table 1.

Thirteen patients (1%) died within 30 days of ASA, and 16 patients (1.3%) experienced intraprocedural and early (within 2 days) postprocedural sustained ventricular tachycardia/ventricular fibrillation requiring electrical cardioversion. Thirty-seven percent of patients (n = 468) had intraprocedural complete heart block, with 151 cases (12%) requiring permanent pacemaker implantation. There was a significant association between higher doses of alcohol and complete heart block (HR, 1.19; 95% CI, 1.05 to 1.35; P = .006). Optimal doses of alcohol appear to be 1.5 to 2.5 mL.

A lower LV outflow tract gradient at the last clinical visit was independently associated with the final NYHA class ≤ 2 (HR, 0.98; 95% CI, 0.97 to 0.99; P < .01).

A total of 171 patients (13%) died during follow-up, resulting in a post-ASA all-cause mortality rate of 2.42 deaths per 100 patient-years (95% CI, 2.07 to 2.82). Significant independent predictors of all-cause mortality included higher age at ASA (HR, 1.06; 95% CI, 1.05 to 1.08; P < .01), septum thickness before ASA (HR, 1.05; 95% CI, 1.01 to 1.09; P < .01), NYHA class before ASA (HR, 1.5; 95% CI, 1.00 to 2.10; P = .047), and the LV gradient at the last check-up (HR, 1.01; 95% CI, 1.00 to 1.01; P = .048).

Sixty-eight patients (5.3%) had a sudden mortality event (0.98 per 100 patient-years; 95% CI, 0.76 to 1.12). The only independent predictor of sudden death was septum thickness before ASA (HR, 1.07; 95% CI, 1.01 to 1.12; P = .014).

“After 2 decades of the introduction of ASA, we can state that this procedure is safe and this procedure is effective,” Prof Veselka said. Because the residual obstruction post ASA is a significant factor influencing both long-term functional status and survival, clinicians should take steps to eliminate LV outflow obstruction in these patients.