The MITRAL (Mitral Implantation of Transcatheter Valves) experiment was the first prospective investigation employing balloon-expandable aortic transcatheter heart valves to treat valve-in-mitral annular calcification (ViMAC), mitral valve-in-ring (MViR), and mitral valve-in-valve (MViV). Beyond a year, procedural results need to be better reported. In the MITRAL trial, researchers assessed 2-year outcomes for ViMAC, MViR, and MViV.

Patients with severe MAC, past failed mitral annuloplasty ring repair, or prior failed bioprosthetic MV replacement at high surgical risk participated in this multicenter prospective trial at 13 U.S. hospitals.

Over 91 patients (31 with ViMAC, 30 with MViR, and 30 with MViV) were enrolled between February 1, 2015, and December 31, 2017. The 2-year all-cause mortality rate in the ViMAC group was 39.3%, 66.7% of participants were functional classes I-II of the New York Heart Association (NYHA), and the mean MV gradient was 5.6±2.0 mm Hg. The 2-year all-cause death rate in the MViR group was 50%, 65% of the patients were NYHA functional classes I-II, and the average MV gradient was 6.5±2.7 mm Hg. The 2-year all-cause death rate in the MViV group was 6.7%, 85% of the patients were NYHA functional classes I-II, and the average MV gradient was 6.9±2.4 mm Hg. All patients had moderate mitral regurgitation at 2 years, and survivors in all 3 groups had persistent improvements in their baseline Kansas City Cardiomyopathy Questionnaire ratings.

In certain patients with severe MAC, a failed annuloplasty ring, and bioprosthetic MV failure, balloon-expandable aortic transcatheter heart valves were linked to improvements in symptoms, quality of life, and stable prosthesis function at a 2-year follow-up. In comparison to the MViV and ViMAC groups. The MViR group had greater death rates between 1 and 2 years.

Reference: jacc.org/doi/10.1016/j.jacc.2022.09.037