Outcomes of transatrial transcatheter mitral valve replacement with a balloon-expandable valve for severe mitral annular calcification

Objective: To evaluate operative and midterm outcomes, including 1-, 3-, and 5-year survival, of transatrial transcatheter mitral valve replacement (TA-TMVR) with a balloon-expandable valve for severe mitral annular calcification (MAC). Methods: We retrospectively reviewed patients with severe MAC who underwent TA-TMVR from 2014 to 2024 using a balloon-expandable prosthesis. Results: Twenty-five patients (68% were female, mean age 75 years) had TA-TMVR for mitral valve disease (92% severe stenosis, 52% moderate-to-severe mitral regurgitation). Previous cardiac surgery was common (48%). Median Society of Thoracic Surgeons Predicted Risk of Operative Mortality was 9% (2%-26%). Most patients were New York Heart Association class III or IV (76%). Preoperative left ventricular ejection fraction was 66%. Concomitant procedures were performed in 68% of cases (aortic valve replacement in 11, septal myectomy in 6, other procedures in 9). A SAPIEN 3 valve was used in 24 patients; most were modified with a felt skirt to improve sealing. Anterior leaflet resection was performed in 24 patients. Operative mortality was 12%. Median length of stay was 14 days. Postoperative left ventricular ejection fraction was 64%, and the mean mitral valve gradient was 5 mm Hg. Paravalvular leak were observed in 6 patients; 3 underwent successful transcatheter closure. One of these patients required a percutaneous valve-in-valve for on-going hemolysis. One-, 3-, and 5-year survival was 68%, 59.5%, and 50.6%, respectively. Conclusions: TA-TMVR with a balloon-expandable valve is a feasible and durable option for high-risk patients with severe MAC and those requiring concomitant procedures, offering an alternative to conventional surgery in anatomically complex or otherwise-inoperable cases.