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.