1-Year Outcomes of Transfemoral Transcatheter Mitral Valve Replacement With the Eos System: The MISCEND Study

Transcatheter mitral valve replacement (TMVR) may benefit patients at high surgical risk with mitral regurgitation (MR).

The authors report 30-day and 1-year outcomes of transfemoral TMVR.

The MISCEND (Edwards Eos Mitral Valve Replacement: Investigation of Safety and Performance After Mitral Valve Replacement With Transcatheter Device) study is a prospective, single-arm, multicenter evaluation of the Eos transcatheter mitral valve replacement system for clinically significant, symptomatic MR. Performance and safety endpoints included device success, procedural success, 30-day rate of MR ≤1+ and 30-day composite major adverse event rate. Additional clinical, echocardiographic, functional, and quality-of-life outcomes were assessed through 1 year.

Sixty patients (median age 79.5 years, Society of Thoracic Surgeons score 5.2%, 40% men, 43.3% with functional MR) were enrolled. Device and procedural success rates were 100.0%. The 30-day composite major adverse event rate was 43.3%, including all-cause mortality (5.0%), all-cause hospitalization (21.7%), nonelective mitral valve reintervention (1.7%), severe bleeding (28.3%), renal complication requiring unplanned dialysis or renal replacement therapy (5.0%), and major cardiac structural complication (8.3%). The rate of MR ≤1+ was 98.1% at 30 days and 100.0% at 1 year, with none/trace MR in 63.0% and 78.4% of patients, respectively. One-year outcomes showed significant improvements in 6-minute walk distance (40.5 m; 95% CI: 13.8-97.2 m; P = 0.003) and Kansas City Cardiomyopathy Questionnaire overall score (17.7 points; 95% CI: 11.2-27.3 points; P < 0.01), with 86.8% of patients in NYHA functional class I/II. Rates of mortality and left ventricular pseudoaneurysm were 20.3% and 10.0%, respectively.

1-year MISCEND results demonstrate the feasibility of TMVR with the Eos system. Although safety concerns related to left ventricular pseudoaneurysm resulted in the cessation of study enrollment, learnings will inform future therapy development.