Transcatheter Mitral Valve Replacement for Severe Mitral Annular Calcification: Primary Outcomes From the SUMMIT-MAC...

Severe mitral annular calcification (MAC) carries significant risk. Safe and effective transcatheter options are needed for patients with MAC.

The goal of this study was to evaluate the safety and effectiveness of the Tendyne Transcatheter Mitral Valve System (Abbott Structural Heart) in symptomatic patients with mitral disease due to severe MAC.

This analysis reports results from the severe MAC cohort of the SUMMIT (Safety and Effectiveness of Using the Tendyne Transcatheter Mitral Valve System for the Treatment of Symptomatic Mitral Regurgitation) study, which was 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 at 12 months' postindex procedure.

Overall, 103 patients (mean age 78.0 ± 6.5 years; 55% female) with severe MAC and mitral regurgitation or stenosis underwent treatment with Tendyne. Mitral regurgitation was present in nearly all patients at baseline (ie, 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 heart failure hospitalization was 60.4% at 12 months (performance goal: 43%; P = 0.0002). Heart failure symptoms improved significantly (NYHA functional 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).

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.