Transcatheter Mitral Valve Repair in Patients With Atrial Functional Mitral Regurgitation

BACKGROUND: Among patients with severe functional mitral regurgitation (FMR), atrial functional mitral regurgitation (aFMR) represents an underrecognized entity. Data regarding outcomes after mitral valve transcatheter edge-to-edge repair (M-TEER) in aFMR remain scarce.

OBJECTIVES: The objective of this study was to analyze the outcome of aFMR patients undergoing M-TEER.

METHODS: Using patients from the international EuroSMR (European Registry of Transcatheter Repair for Secondary Mitral Regurgitation) registry undergoing M-TEER for FMR, the authors analyzed baseline characteristics and 2-year outcomes in aFMR in comparison to non-aFMR and ventricular FMR. Additionally, the impact of right ventricular dysfunction (RVD) (defined as right ventricular to pulmonary artery uncoupling) on outcome after M-TEER was assessed.

RESULTS: Among 1,608 FMR patients treated by M-TEER, 126 (7.8%) were categorized as aFMR. All 126 aFMR patients had preserved left ventricular function without regional wall motion abnormalities, left arterial dilatation and Carpentier leaflet motion type I. Procedural success (defined as mitral regurgitation ≤2+ at discharge) was 87.2% (P < 0.001) and New York Heart Association (NYHA) functional class significantly improved during follow-up (NYHA functional class III/IV: 86.5% at baseline to 36.6% at follow-up; P < 0.001). The estimated 2-year survival rate in aFMR patients was 70.4%. Two-year survival did not differ significantly between aFMR, non-aFMR, and ventricular FMR. Besides NYHA functional class IV, RVD was identified as a strong independent predictor for 2-year survival (HR: 2.82 [95% CI: 1.24-6.45]; P = 0.014).

CONCLUSIONS: aFMR is a frequent cause of FMR and can be effectively treated with M-TEER to improve symptoms at follow-up. Advanced heart failure symptoms and RVD were identified as important risk factors for survival in aFMR patients.