OBJECTIVES: we sought to determine whether patients with functional mitral regurgitation (FMR) would benefit from ventricular reshaping by the Coapsys device (Myocor, Inc., Maple Grove, Minnesota). BACKGROUND: FMR occurs when ventricular remodeling impairs valve function. Coapsys is a ventricular shape change device placed without cardiopulmonary bypass to reduce FMR. It compresses the mitral annulus and reshapes the ventricle. We hypothesized that Coapsys for FMR would improve clinical outcomes compared with standard therapies. METHODS: RESTOR-MV (Randomized Evaluation of a Surgical Treatment for Off-Pump Repair of the Mitral Valve) was a randomized, prospective, multicenter study of patients with FMR and coronary disease with core laboratory analysis. After enrollment, patients were stratified to the standard indicated surgery: either coronary artery bypass graft alone or coronary artery bypass graft with mitral valve repair. In each stratum, randomization was to either control (indicated surgery) or treatment (coronary artery bypass graft with Coapsys ventricular reshaping). RESULTS: the study was terminated when the sponsor failed to secure ongoing funding; 165 patients were randomized. Control and Coapsys both produced decreases in left ventricular (LV) end-diastolic dimension and MR at 2 years (p < 0.001); Coapsys provided a greater decrease in LV end-diastolic dimension (p = 0.021). Control had lower MR grades during follow-up (p = 0.01). Coapsys showed a survival advantage compared with control at 2 years (87% vs. 77%) (hazard ratio: 0.421; 95% confidence interval: 0.200 to 0.886; stratified log-rank test; p = 0.038). Complication-free survival (including death, stroke, myocardial infarction, and valve reoperation) was significantly greater with Coapsys at 2 years (85% vs. 71%) (hazard ratio: 0.372; 95% confidence interval: 0.185 to 0.749; adjusted log-rank test; p = 0.019). CONCLUSIONS: analysis of RESTOR-MV indicates that patients with FMR requiring revascularization treated with ventricular reshaping rather than standard surgery had improved survival and a significant decrease in major adverse outcomes. This trial validates the concept of the ventricular reshaping strategy in this subset of patients with heart failure. (Randomized Evaluation of a Surgical Treatment for Off-Pump Repair of the Mitral Valve [RESTOR-MV]; NCT00120276).