Abstract 12382: The Significance of Cardiac Resynchronization Therapy in Eligible Patients Undergoing Transcatheter Edge-to-Edge Repair for Functional Mitral Regurgitation

Introduction: Current guidelines prioritize the utilization of cardiac resynchronization therapy (CRT) over transcatheter edge-to-edge repair (TEER) in eligible patients with functional mitral regurgitation (FMR). However, the data in support of this recommendation are limited. Objective: To examine the effect of performing TEER for FMR in patients without prior CRT. Methods: This is a single-center, retrospective analysis encompassing 440 days (IQR, 135-915 days) of follow-up after TEER for FMR in patients who fulfilled guideline criteria for CRT. The study cohort was divided according to CRT status prior to the procedure. The primary outcome was the composite of all-cause mortality and heart failure hospitalization at one year. Secondary outcomes included components of the primary outcome, as well as 1-year all-cause hospitalization, and 1-month MR severity, indexed left atrial volume, and indexed left ventricular mass. Results: A total of 126 patients were included in the analysis, of whom 70 (56%) did not have CRT at the time of TEER. Baseline characteristics and immediate procedural success were mostly comparable between those with and those without CRT. The no-CRT group experienced higher rates of the primary outcome (43% vs 25%, p=0.041), which were accounted for by increased mortality (26% vs 11%, p=0.033). After multivariate analysis, the absence of CRT was associated with more than twice the risk of the primary outcome (HR 2.36, 95% CI 1.1-4.98, p=0.024). Secondary endpoints did not differ between the groups. Conclusions: In CRT eligible patients undergoing mitral TEER for FMR, 1-year outcome is less favorable when the procedure is not preceded by CRT.