Meta-analyses of septal reduction therapies for obstructive hypertrophic cardiomyopathy: comparative rates of overall mortality and sudden cardiac death after treatment.

BACKGROUND: Septal reduction for obstructive hypertrophic cardiomyopathy may be performed by surgical myectomy or alcohol septal ablation (ASA). Unlike surgical myectomy, ASA creates an intramyocardial scar that may potentiate the risk of ventricular arrhythmias and sudden cardiac death (SCD). METHODS AND
RESULTS: Systematic reviews for ASA and surgical myectomy were performed. Study selection and data extraction were completed independently by 2 investigators. Comparative data analyses were completed using a random effects model and regression analysis. Kappa statistics for agreement on initial study inclusion were high for both ASA (0.78; 95% CI, 0.68 to 0.88) and surgical myectomy studies (0.95; 95% CI, 0.84 to 1.0). Nineteen ASA studies (2207 patients) and 8 surgical myectomy studies (1887 patients) were included. Median follow-up was shorter for ASA than for myectomy studies (51 versus 1266 patient-years; P<0.001). For ASA and surgical myectomy, unadjusted rates (events/patient-years) of all-cause mortality (0.021 versus 0.018, respectively; P=0.37) and SCD (0.004 versus 0.003, respectively; P=0.36) were similar. Patients treated with ASA were older (weighted mean, 55 versus 44 years; P<0.001) and had less septal hypertrophy (weighted mean, 21 versus 23 mm; P<0.001) compared with those treated with myectomy. After adjustment for available baseline characteristics, odds ratios for treatment effect on all-cause mortality and SCD were 0.28 (95% CI, 0.16 to 0.46) and 0.32 (95% CI, 0.11 to 0.97), respectively, favoring ASA.
CONCLUSIONS: Rates of all-cause mortality and SCD after both ASA and surgical myectomy were similarly low. Adjusted for baseline characteristics, the odds ratios for treatment effect on all-cause mortality and SCD were lower in ASA cohorts compared with surgical myectomy cohorts.