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

INTRODUCTION: This umbrella review aims to evaluate the certainty and consistency of the available evidence rather than to provide a new procedural comparison. We combined systematic reviews that looked at surgical septal myectomy (SM) and alcohol septal ablation (ASA) for treating symptoms of obstructive hypertrophic cardiomyopathy (oHCM) 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 encompassing 33 distinct primary studies and 12,860 patients were incorporated, indicating substantial study overlap. ASA was associated with a significantly higher risk of reintervention compared to SM, supported by high-certainty evidence. On the other hand, for all other results, like death rates and the need for permanent pacemakers, the evidence was often considered very weak because it was inconsistent and unclear. CONCLUSION: Strong evidence shows that SM is a longer-lasting treatment for oHCM, as it leads to fewer reinterventions. The evidence for mortality outcomes is of very low certainty, making it impossible to draw firm conclusions about which technique is better. This review identifies current knowledge gaps regarding survival benefits to inform clinical practice and future research.