JACC Cardiovasc Interv. 2026 Oct 31:S1936-8798(26)02917-1. doi: 10.1016/j.jcin.2026.10.013. Online ahead of print.
ABSTRACT
BACKGROUND: Secondary mitral regurgitation (MR) contributes to morbidity and mortality in patients with symptomatic valve disease. Although transcatheter edge-to-edge repair is beneficial, many patients remain suboptimal candidates. Posterior leaflet restoration (PLR) provides a prosthetic coaptation surface via an adaptive coaptation element that inflates during systole and deflates during diastole to facilitate leaflet coaptation.
OBJECTIVES: This study aims to evaluate the safety and feasibility of PLR using the MRace implant (Polares Medical, Inc).
METHODS: Early Feasibility Experience of Posterior Leaflet Restoration to Reduce Mitral Regurgitation Using the MRace Implant in Georgia and Brazil (EXPLORE MR) enrolled 78 symptomatic patients with severe secondary MR (≥3+), stratified post hoc by left ventricular end-diastolic volume: nonseverely enlarged left ventricle (NSELV) (N = 46) and severely enlarged left ventricle (SELV) (N = 32). The primary endpoint was 30-day mortality; secondary endpoints were MR reduction and functional outcomes.
RESULTS: The implant was successfully deployed in 96.2% of patients. All-cause mortality at 30 days was 6.4%. MR ≤2+ was achieved in 93.8% of patients at 30 days and was sustained in 90.6% at 1 year. Patients with NSELV showed better results in MR ≤1+ at every time point (94.4% at 30 days, 89.5% at 1 year) compared with the SELV group (79.3% and 69.2%, respectively). The NSELV subgroup demonstrated better functional recovery, with NYHA functional class I or II rising from 8.7% to 84.2%, vs a more attenuated response in the SELV group (15.6%-76.9%). The 6-minute walk test improved in the paired NSELV cohort (Δ +93.9 m), but not in paired patients with SELV (Δ -7.8 m). Kaplan-Meier 1-year all-cause mortality was 29.5% overall and was better in patients with NSELV (19.4%) than in SELV (41.7%).
CONCLUSIONS: PLR with the MRace implant achieves substantial MR reduction and meaningful functional improvement, most pronounced in patients without severely enlarged left ventricles. (XPLORE MRace [BR]: Early Feasibility Experience of Posterior Leaflet Restoration to Reduce Mitral Regurgitation Using the MRace Implant [EXPLORE MRace]; NCT06113354).
PMID:42967235 | DOI:10.1016/j.jcin.2026.10.013