Two-Year Clinical and Hemodynamic Outcomes After Transcatheter Mitral Valve Replacement in Severe Mitral Annular Calcification

The SUMMIT-MAC trial is evaluating the safety and effectiveness of the Tendyne Transcatheter Mitral Valve Replacement (TMVR) system in patients with severe mitral annular calcification (MAC). Primary outcomes demonstrated significant improvements in mitral regurgitation severity, heart failure symptoms, and quality-of-life; leading to FDA approval of Tendyne. Intermediate term TMVR outcomes have not been reported. The SUMMIT-MAC cohort (NCT03433274) enrolled high surgical-risk patients with severe MAC (average volume 5,679 ± 5,670; range 741 to 37,437 mm3) and significant mitral valve dysfunction. Independent assessments of mitral disease were performed at an echocardiography core laboratory and adverse events were adjudicated by a clinical events committee. Two-year follow-up visits were achieved in 95% of available patients, with an average follow-up of 18.7 months. The cohort included 103 patients from 37 sites. Mean age was 78.0±6.5 years, 55% were women, 74% were in NYHA functional class III/IV, and mitral regurgitation was present in nearly all patients at baseline (97% grade >2+). At 2 years all-cause mortality was 32.3% (32 patients) and cardiovascular mortality was 23.6% (23 patients). 97% (56/58) of patients with available echocardiograms at 2 years had ≤1+ mitral regurgitation. Additionally, at 2 years, 84% of patients were in NYHA functional class I/II and quality-of-life improved significantly (KCCQ-OS, Δ24.2±19.6 points; p<0.0001). In a high-risk cohort of patients with mitral valve disease and severe MAC, Tendyne TMVR had acceptable sustained clinical outcomes and quality-of-life over 2 years. The reduction of mitral regurgitation severity was sustained through 2-years post TMVR.