Aims Functional mitral regurgitation (FMR) contributes to morbidity and mortality in heart failure (HF) patients. The aim of this study was to determine whether percutaneous mitral annuloplasty could safely and effectively reduce FMR and yield durable long-term clinical benefit.Methods and resultsThe impact of mitral annuloplasty (Carillon Mitral Contour System) was evaluated in HF patients with at least moderate FMR. Patients in whom the device was placed then acutely recaptured for clinical reasons served as a comparator group. Quantitative measures of FMR, left ventricular (LV) dimensions, New York Heart Association (NYHA) class, 6 min walk distance (6MWD), and quality of life were assessed in both groups up to 12 months. Safety and key functional data were assessed in the implanted cohort up to 24 months. Thirty-six patients received a permanent implant; 17 had the device recaptured. The 30-day major adverse event rate was 1.9. In contrast to the comparison group, the implanted cohort demonstrated significant reductions in FMR as represented by regurgitant volume [baseline 34.5 ±11.5 mL to 17.4 ±12.4 mL at 12 months (P < 0.001)]. There was a corresponding reduction in LV diastolic volume [baseline 208.5 ±62.0 mL to 178.9 ±48.0 mL at 12 months (P = 0.015)] and systolic volume [baseline 151.8 ±57.1 mL to 120.7 ±43.2 mL at 12 months (P = 0.015)], compared with progressive LV dilation in the comparator. The 6MWD markedly improved for the implanted patients by 102.5 ±164 m at 12 months (P = 0.014) and 131.9 ±80 m at 24 months (P < 0.001).ConclusionPercutaneous reduction of FMR using a coronary sinus approach is associated with reverse LV remodelling. Significant clinical improvements persisted up to 24 months. © 2012 The European Society of Cardiology.