Impact of anatomical complexity in Mitral Transcatheter Edge-To-Edge Repair (M-TEER) outcomes in patients with primary mitral regurgitation (PMR) at high or prohibitive surgical risk are scarce and conflicting.

The aim of this study was to assess mid-term prognosis after M-TEER and identify prognostic factors according to PMR aetiology and anatomy.

Patients who underwent M-TEER for PMR between July 2013 and October 2023 at two high-volume centres in Switzerland were classified according to the anatomy: A2P2 Prolapse/Flail vs Non-A2P2 Prolapse/Flail. In a sub-group of patients, we estimated survival after M-TEER based on mitral valve (MV) anatomical complexity (defined as presence of≥1 of the following criteria:≥moderate calcifications, Barlow disease, multiple or commissural prolapses).

A total of 315 patients (mean age 82.2 (±6.3) years, 46.3% female,EuroScore II 5.1% (±4.1)) with symptomatic PMR (15.6% grade 3+, 84.4% grade 4+) underwent M-TEER. WIth a median follow up of 13 months, compared with the Non-A2P2 Prolapse/Flail group, the A2P2 Prolapse/Flail group demonstrated more effective reduction in MR at discharge (residual MR≤1+: 70.5% vs. 60.4%, P=0.031). A2P2 Prolapse/Flail group showed superior symptomatic improvement at 1 year (NYHA class≤II: 91.4% vs. 74.5%, P=0.017). No significant difference was observed between both groups in all-cause mortality at 1 year (15.1% vs. 18.8%, P=0.492). In a subgroup of patients classified according to MV anatomy (n=143), patients with complex MV anatomy (n=68) had a higher all-cause mortality at a median last follow-up of 22 months compared with patients with non-complex MV anatomy (51.5% vs 34.7%, P=0.042). Using multivariate analysis, complex MV anatomy (HR 10.01 [1.30–77.04], P=0.027) and severe renal failure (HR 19.80 [2.68–146.04], P=0.003) were identified as predictors of 1-year mortality (Figure 1, Figure 2).

Complex anatomical characteristics are strongly associated with poorer outcomes in patients with PMR undergoing M-TEER.