Abstract
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.