Systematic Review Certainty of Evidence and Procedural Durability of Septal Reduction Therapies in Obstructive Hypertrophic Cardiomyopathy: An Umbrella Review of Meta-Analyses.

Abstract

Introduction: This umbrella review aimed to evaluate the certainty and consistency of the available evidence rather than to provide a new procedural comparison. We synthesized systematic reviews comparing surgical septal myectomy (SM) versus alcohol septal ablation (ASA) for symptomatic obstructive hypertrophic cardiomyopathy (oHCM) to critically assess the certainty of findings.

Methods: An umbrella review of meta-analyses was conducted following Cochrane and PRISMA guidelines. A systematic search of four databases was performed. Methodological quality, risk of bias, and study overlap were assessed. Quantitative synthesis was performed using a random-effects model, and the certainty of evidence was classified using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Results: Six meta-analyses comprising 31 unique primary studies and 12,860 patients were included, demonstrating very high study overlap. ASA was associated with a significantly higher risk of reoperation compared to SM, supported by high-certainty evidence. Conversely, for all other outcomes, including mortality and permanent pacemaker implantation, the certainty of evidence was consistently classified as very low due to inconsistency and imprecision.

Conclusion: High-certainty evidence supports SM as the more durable intervention for oHCM, demonstrated by a reduced need for reoperations. Notably, the evidence for mortality outcomes is of very low certainty, precluding definitive conclusions regarding clinical equivalence or technique superiority. This review identifies current knowledge gaps regarding survival benefits to inform clinical practice and future research.