Multiple-Branch Alcohol Septal Ablation Is Associated with Reduced Cardiovascular Events: Insights from a Trans-Pacific Multicentre Registry.

Background: Alcohol septal ablation (ASA) is an established intervention for patients with drug-refractory obstructive hypertrophic cardiomyopathy. Whereas some patients require ASA with multiple target septal branches due to a residual pressure gradient, the prognostic effect of multiple-branch ablation remains unclear. Thus, we aimed to investigate the association of multiple-branch ablation with cardiovascular (CV) events after ASA. Methods: This multicentre trans-Pacific study enrolled patients who underwent ASA at 4 institutions in the US and Japan. Patients were categorized into single- and multiple-branch ablation groups. CV events, defined as a composite of CV death, repeated septal reduction therapy, and heart failure hospitalization, were compared in 2 groups within 1 year after ASA was performed. To address potential confounding, inverse probability of treatment weighting (IPTW) was performed, based on the propensity scores for multiple-branch ablation. Odds ratios (ORs) were examined for CV events before and after the IPTW was performed. Results: This study enrolled 151 patients who underwent ASA (single-branch, n = 66; multiple-branch, n = 85). The multiple-branch ablation group had higher peak gradients, which became comparable after ASA was performed. CV events were significantly lower in the multiple-branch ablation group, both before the IPTW (OR 0.33, 95% confidence interval [CI] 0.10-0.96, Conclusions: This study demonstrated that ASA with multiple target branches may be an effective treatment option for reducing CV events in morphologically and hemodynamically eligible patients with obstructive hypertrophic cardiomyopathy.