Transcatheter Mitral Valve Replacement for Severe Mitral Annular Calcification

BACKGROUND Severe mitral annular calcification (MAC) carries significant risk. Safe and effective transcatheter options are needed for these patients. OBJECTIVE To evaluate the safety and effectiveness of the Tendyne Transcatheter Mitral Valve System in symptomatic patients with mitral disease due to severe MAC. METHODS The SUMMIT-MAC study is the first prospective clinical trial designed to assess the use of the Tendyne system for severe MAC. All patients had severe MAC with significant mitral valve dysfunction and were at high surgical risk. An echocardiography core laboratory performed independent assessments of mitral disease. Adverse events were adjudicated by an independent clinical events committee. The primary endpoint was freedom from all-cause mortality and heart failure hospitalization (HFH) at 12 months post-index procedure. RESULTS Overall, 103 patients (78.0±6.5 years; 55% women) with severe MAC and mitral regurgitation (MR) or stenosis underwent treatment with Tendyne. MR was present in nearly all patients at baseline (i.e., 97% of patients with grade >2+). Technical success was achieved in 94.2%, with a 30-day mortality of 6.8%. The primary endpoint was met - freedom from all-cause mortality and HFH was 60.4% at 12 months (performance goal: 43%; p=0.0002) Heart failure symptoms improved significantly (NYHA Class I/II, 30.6% vs. 87.5%, paired baseline vs 12 months; p<0.0001) and quality-of-life improved significantly (mean paired increase in the Kansas City Cardiomyopathy Questionnaire overall summary, 18.7±24.4 points; p<0.0001). CONCLUSION In this first report of the primary outcomes of the SUMMIT-MAC clinical trial, transcatheter mitral valve replacement with Tendyne led to successful treatment of mitral valve disease due to MAC and significant improvements in heart failure symptoms and quality-of-life.