Comparative Analysis of Clinical, Echocardiographic, and Hemodynamic Features Across Functional Mitral Regurgitation Subtypes

Functional mitral regurgitation (FMR) includes atrial (aFMR), ventricular (vFMR), or combined atrial and ventricular (avFMR) phenotypes. This study evaluated differences in clinical, echocardiographic, and invasive hemodynamic features among aFMR, vFMR, and avFMR in patients undergoing transcatheter edge-to-edge repair (TEER). We retrospectively analyzed patients who underwent TEER for significant FMR at the Cleveland Clinic from 2019 to 2023. FMR was diagnosed in patients with structurally normal mitral leaflets and regurgitation secondary to atrial or ventricular remodeling. aFMR was defined by isolated left atrial (LA) dilation (left atrial volume index ≥40 mL/m²) without left ventricular (LV) dysfunction; vFMR by LV dysfunction without LA dilation; and avFMR by both. A total of 127 patients were included. Mean age was 71.7 years, and 59% were male. Thirty patients (24%) had aFMR, 23 (18%) had vFMR, and 74 (58%) had avFMR. aFMR patients had higher lateral/septal e' and lower E/e'. LV volumes, LVEF, and LV global longitudinal strain were more impaired in vFMR/avFMR. aFMR patients had lower baseline LA mean pressure (p=0.031) and V-wave (p=0.012). After TEER, all groups demonstrated significant reductions in LA pressures, with no adjusted differences in post-procedural LA mean pressure (p=0.140) or V-wave (p=0.238). Procedural success (MR ≤2+) was high across groups (94%). In conclusion, FMR phenotype is associated with differences in echocardiographic and hemodynamic profiles, with lower baseline LA pressures in aFMR. All subtypes showed favorable reductions in LA pressures and V-waves after TEER, with high procedural success, supporting TEER as an effective therapy across FMR subtypes.