National experience of alcohol septal ablation in patients with obstructive hypertrophic cardiomyopathy: A long-term multicenter retrospective study.

Objectives: Hypertrophic cardiomyopathy (HCM) is a widespread disease with an incidence of 1:200 in the general population and its surgical and interventional treatment is well-developed in western countries. This study is focusing on outcomes of HCM patients after alcohol septal ablation in Russian Federation.

Methods: We conducted a multicenter registry to evaluate outcomes of obstructive hypertrophic cardiomyopathy (oHCM) patients after ASA. Our study was focused on the following outcomes: (i) 30-day mortality, (ii) 30-day permanent pacemaker implantations, (iii) a residual obstruction occurrence, (iv) final maximal left ventricular outflow tract gradient, (v) long-term mortality, (vi) final heart failure functional class, (vii) freedom from sudden cardiac death. We conducted secondary analysis to assess outcomes in patients with single versus repeated ASA. The mean follow-up was 71±47 months.

Results: A total of 597 consecutive patients (54.9% female) were enrolled in the Russian Alcohol Septal Reduction (RASA) registry from three interventional groups. The mean age was 56±14 years. Thirty-day mortality rate was 0.7% (4 patients). Permanent pacemakers were implanted in 42 (7%) cases in 30-days follow-up. The resting LVOT gradient reduced from 64±28 to 20±13 mmHg (P<0.0001), and the mean NYHA class decreased from 2.3±0.7 to 1.3±0.5 (P<0.001). Long-term survival rates were as follows: 97.4 (95%CI: 96.2-98.7) %, 93.2 (95%CI: 91.0-95.3) %, 84.9 (95%CI: 80.7-89.4) % at 1-, 5-, 10-year follow-up, respectively. Patients after repeated ASA had similar long-term survival comparing to those who underwent single ASA (weighted log rank P value = 0.254). Heart failure class in the long-term and final gradient at the last follow-up were not statistically different between groups under study (P>0.05).

Conclusions: In our registry, alcohol septal ablation in patients with obstructive hypertrophic cardiomyopathy was safe in the short- and long-term follow-up. Outcomes of patients underwent repeated ASA were non-inferior to those after single ASA.