Alcohol septal ablation versus surgical septal myectomy of obstructive hypertrophic cardiomyopathy: systematic review and meta-analysis

OBJECTIVES: To elucidate the optimal septal reduction therapy for obstructive hypertrophic cardiomyopathy, we conducted a meta-analysis comparing alcohol septal ablation (ASA) and septal myectomy. METHODS: MEDLINE, EMBASE and Cochrane CENTRAL were searched to identify studies investigating the outcomes of ASA and septal myectomy in patients with obstructive hypertrophic cardiomyopathy in January 2023. The primary outcome of interest was all-cause mortality in studies with ≥1 year of follow-up. The secondary outcomes of interest comprised left ventricular outflow tract (LVOT) pressure gradient reduction and reoperations of LVOT. A subgroup analysis of all-cause mortality including studies with follow-up ≥5 years was performed. RESULTS: 27 observational studies were included (15 968 patients). Analysis demonstrated similar all-cause mortality [hazard ratio (HR) (95% confidence interval) (CI) 1.24 (0.88-1.76); P = 0.21; I2 = 56%]. In contrast, ASA was associated with less reduction of LVOT pressure gradient and a reoperation rate [weighted mean difference (95% CI) 11.04 mmHg (5.60-16.48); P < 0.01; I2 = 64%, HR (95% CI) 9.14 (6.55-12.75); P < 0.001; I2 = 0%, respectively]. The subgroup analysis with follow-up ≥5 years revealed higher long-term mortality with ASA [HR (95% CI) 1.50 (1.04-2.15); P = 0.03; I2 = 52%]. CONCLUSIONS: Although both septal reduction therapies were associated with similar all-cause mortality, ASA was associated with a higher rate of reoperation and less reduction of LVOT pressure gradient. Furthermore, all-cause mortality with follow-up ≥5 years showed favourable outcomes with septal myectomy, although the result is only hypothesis-generating given a subgroup analysis.