Atrial fibrillation and clinical outcomes after mitral transcatheter edge-to-edge repair: A mechanism-stratified cohort study

Background: Mitral regurgitation (MR) and atrial fibrillation (AF) both contribute to heart failure (HF) morbidity and mortality. Transcatheter edge-to-edge repair (TEER) is an established treatment for MR in high surgical risk patients. The combined impact of AF and MR mechanisms on TEER outcomes is not yet investigated. Methods: Patients who underwent TEER were classified by MR mechanism: degenerative (DMR), atrial functional (aFMR) or ventricular functional (vFMR). The cohort was further stratified by combination of MR mechanism and baseline AF status. The primary endpoint was event-free survival (freedom from HF hospitalization or all-cause mortality), estimated by Kaplan-Meier. Multivariate Cox regression adjusted for confounders. Results: This study included 221 consecutive TEER procedures; AF was present in 50.2 % of patients. TEER achieved reduction in MR severity and immediate left-atrial unloading across mechanisms. One-year survival and event-free survival were 87.8 % and 74.7 %, respectively. Event-free survival was lower with AF than with sinus rhythm (P = 0.027), and higher in DMR than with FMR (P = 0.016). In multivariable analysis, AF remained independently associated with the composite outcome. When mechanism and rhythm were combined, aFMR and vFMR with AF carried ∼3-fold higher adjusted hazards versus DMR without AF (adjHR∼2.7–3.0). Conclusions: AF, more than MR mechanism, was strongly associated with HF hospitalization or death after TEER; the poorest clinical outcomes were observed in aFMR and in vFMR with AF despite similar acute MR reduction and left-atrial unloading. These findings support the hypothesis that in significant MR without AF, earlier TEER may improve outcome before AF develops.