Abstract 12588: Invasive Therapies Reduce Cardiovascular Death but Not Sudden Cardiac Death in Obstructive Hypertrophic Cardiomyopathy

Background: Data on survival after medical therapy, alcohol septal ablation (ASA) and myectomy of Asian patients with obstructive hypertrophic cardiomyopathy (HCM) were lacking. Besides, long-term effects of ASA and myectomy, especially on sudden cardiac death were controvertial. Hypothesis: We assessed the hypothesis that patients with obstructive HCM who were treated with invasive therapy had a favorable survival, similar to that of patients with non-obstructive HCM. Methods: This study included 1,065 consecutive patients with HCM (mean age 48±13 years, 64.3% male ) from 4 centers. A total of 750 patients (70.4%) had left ventricular outflow tract gradients ≥ 50 mm Hg, of whom 254 (23.8%) were treated medically, 236 (22.2%) underwent ASA, and 260 (24.4%) underwent myectomy. Primary endpoints were and aborted cardiac arrest. Results: The mean follow-up period was 5.5±3.7 years. The 5- and 10-year endpoint-free survival rates were similar among ASA patients(94.6% and 93.6%), myectomy patients (93.8% and 91.2%), and non-obstructive patients (95.6% and 93.4%), and better than that of medical therapy (85.9%, and 81.6%; log-rank p =0.004, = 0.025 and <0.001, respectively). The incidence of sudden cardiac death was similar among the ASA group (2.2%), myectomy group (1.6%), medically treated group (3.5%) and non-obstructive HCM (1.6%) (P=0.53). For the total study population, independent determinants of the endpoints were female (HR: 1.65, 95% CI: 1.03-2.66, P=0.037), unexplained syncope (HR: 1.70, 95% CI: 1.07-2.71, P=0.026), and left atrial diameter (HR: 1.06, 95% CI: 1.03-1.10, P<0.001). For the obstructive HCM patients, invasive therapy (HR: 0.50, 95% CI: 0.29-0.88, P=0.016), female (HR: 1.82, 95% CI:1.06-3.12, P=0.03) and left atrial diameter (HR: 1.05, 95% CI: 1.01-1.09, P=0.01) were independently associated with primary endpoints. Conclusions: ASA and myectomy in patients with obstructive HCM have a low incidence of cardiovascular death, similar to that of patients with non-obstructive HCM. But sudden cardiac death was not improved after invasive therapies.