Midterm Outcomes of Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation According to Anatomical Characteristics.

Background Mitral transcatheter edge-to-edge repair (M-TEER) is an established option for high-risk primary mitral regurgitation (PMR) patients, but data on the impact of anatomical complexity on prognosis are scarce and conflicting. Objectives The aims of this study were to characterize patients with severe PMR undergoing M-TEER, assess mid-term prognosis after M-TEER, and identify prognostic factors based on PMR mechanism. Methods Data from symptomatic PMR patients with severe PMR treated with M-TEER between July 2013 and October 2023 at two Swiss centers were collected retrospectively until 2017 and prospectively thereafter. Patients were categorized by lesion type: A2-P2 prolapse/flail vs. non-A2-P2 prolapse/flail. A subset was classified by mitral valve (MV) anatomical complexity (defined by the presence of ≥1 of the following: ≥moderate calcifications, Barlow's disease, multiple prolapses, or commissural prolapses). Cox regression identified predictors of 1-year all-cause mortality. Results Among 315 patients (mean age 82.2 ± 6.3 years, 46.3% female, European System for Cardiac Operative Risk Evaluation II 5.1% ± 4.1%) followed for a median (interquartile range [IQR]) of 13 months (5-33), technical success was 93.0%. Compared with the non-A2-P2 prolapse/flail group (n = 186), the A2-P2 prolapse/flail group (n = 129) had better echocardiographic outcomes at discharge (residual mitral regurgitation [MR] ≤ 1+: 70.5 vs. 60.4%; p = 0.031) and superior symptomatic improvement at 1 year (New York Heart Association class ≤ II: 91.4 vs. 74.5%; p = 0.017) but similar 1-year all-cause mortality (15.1 vs. 18.8%; p = 0.492). Among patients classified by MV anatomical complexity (n = 143), patients with complex MV anatomy (n = 68) had a higher mortality at a median (IQR) follow-up of 22 months (9-36) compared to those with noncomplex MV anatomy (n = 75) (51.5 vs. 34.7%; p = 0.042). Multivariate analysis identified complex MV anatomy and severe renal failure as predictors of 1-year all-cause mortality. Conclusions MV anatomical characteristics have a significant influence on symptomatic improvement and all-cause mortality at 1 year and should be carefully considered during the selection of PMR patients for M-TEER.