Causes and predictors of mortality after transcatheter mitral valve implantation in patients with severe mitral annulus calcification

Objectives To evaluate the causes and predictors of mortality after valve-in-mitral annulus calcification (MAC) transcatheter mitral valve implantation (TMVI). Background Conventional surgical mitral valve replacement is associated with a high risk in patients with mitral valve disease associated with severe MAC. In this population, TMVI may be an attractive alternative option. However, its prognostic factors are poorly understood. Methods All patients undergoing valve-in-MAC TMVI from 2013 to 2018 in our center were included. Indication for TMVI relied on the judgment of the local heart team. Patients were followed at 30 days and 1 year. Results A total of 34 patients underwent valve-in-MAC TMVI. The mean age was 79 +/- 11 years and 73% of patients were women. Their mean EuroSCORE 2 was 8 +/- 7%. The transseptal approach was used in 79% of patients and a hybrid transatrial in 29%. Balloon expandable transcatheter heart valves were used in all the patients. Technical success was achieved in 76% of the patients. Thirty-day and 1-year all-cause mortality rates were 14.7% and 32.4%, respectively. The main two causes of 1-year mortality were congestive heart failure (8.8%) and infective endocarditis (5.9%). In multivariate analysis, the only predictor of 1-year mortality was the presence of periprothetic mitral regurgitation grade 2 (HR, 5.69; 95%CI, 1.59-27.88, p = 0.032). Conclusion Early and mid-term mortality remains high after valve-in-MAC TMVI and seems to be associated with the presence of paravalvular mitral regurgitation. However, whether the latter is a prognostic factor or marker remains to be determined to improve clinical outcomes in this high-risk population.