Outcome of Patients Having Transcatheter Mitral Valve Implantation for the Treatment of Degenerated Mitral Bioprostheses.

Transcatheter mitral valve implantation (TMVI) is at various levels of preclinical investigation and has proven to be more challenging than transcatheter aortic valve implantation due to more complex anatomy. The purpose of this study is to evaluate the short-term and long-term outcomes of high-risk patients who underwent TMVI for degenerated mitral bioprostheses. In this retrospective, observational study, we reviewed data on the first 26 patients with previous surgical mitral valve replacement or repair with annular ring that underwent TMVI using the balloon-expandable heart-valve system at our institution from 2014 to 2019. We reviewed pre/postprocedure echocardiographic data, in-hospital, 30-day data and 1-year outcomes. The indication for TMVI was mitral regurgitation (MR) in 9 patients, mitral stenosis in 9 patients and mixed mitral disease in 8 patients. There was a 100% device implantation success rate and a 96% in-hospital survival rate. Survival was 96% at 30 days and 85% at 1 year. Mean mitral gradient (MMG) improved postprocedure (13.3 mm Hg to 6.8 mm Hg, p <0.0001) and was sustained at 1 year (13.3 mm Hg to 7.2 mm Hg, p <0.0001). MR grade improved postprocedure (3+ to 1+, p <0.0001) and was sustained at 1 year (3+ to 0, p <0.0001). Additionally there was significant 30-day and 1-year improvements in patients' Kansas City Cardiomyopathy Questionnaire score after TMVI (47.8 to 75.7 to 84.0, p = <0.0001). In conclusion, our early experience with treatment of degenerated mitral bioprostheses using TMVI in high-risk patients resulted in significant short-term and sustained long-term improvements in mean mitral gradient, MR and heart failure symptoms.