Mitral Transcatheter Edge-to-Edge Repair in Ventricular Functional Mitral Regurgitation and Very Severe Left Ventricular Dysfunction

BACKGROUND: Patients with functional mitral regurgitation (MR) and very severe left ventricular (LV) dysfunction (LV ejection fraction [LVEF] <20%) have been largely excluded from randomized trials of mitral transcatheter edge-to-edge repair (M-TEER), leaving a substantial knowledge gap regarding the role of M-TEER in this high-risk population. OBJECTIVES: This study aimed to evaluate the safety, feasibility, and 1-year outcomes of M-TEER in patients with functional MR and LVEF <20%. METHODS: The OCEAN (Optimized Catheter Valvular Intervention)-Mitral registry prospectively enrolled patients undergoing M-TEER. Among patients with functional MR and LVEF ≤40% (n = 1,538), outcomes were compared between those with LVEF <20% (n = 103) and 20%≤ LVEF ≤40% (n = 1,435). The primary endpoint was the composite of all-cause death and heart failure (HF) hospitalization at 1 year. Secondary endpoints included cardiovascular (CV) death and procedural outcomes. RESULTS: Acute procedural success was similar between groups (n = 103 [100%, LVEF <20%] vs n = 1,390 [97%, 20%≤ LVEF ≤40%]), with comparable residual MR and postprocedural transmitral pressure gradients. In-hospital mortality did not differ by LVEF category (n = 5 [5%] vs n = 58 [4%]). Both groups showed significant improvement in NYHA functional class at 1 year, although functional status remained worse in patients with LVEF <20%. After adjustment, the primary endpoint did not differ significantly between groups (LVEF <20% vs 20%≤ LVEF ≤40%; HR: 1.24; 95% CI: 0.82-1.88). However, LVEF <20% was independently associated with higher CV mortality (HR: 2.00; 95% CI: 1.08-3.68). CONCLUSIONS: In patients with ventricular functional MR and LVEF <20%, M-TEER was feasible and associated with meaningful symptomatic improvement without excess risk of death or HF hospitalization, although CV mortality remained higher, likely reflecting advanced myocardial disease.