Influence of Mitral Regurgitation Repair on Survival in the Surgical Treatment for Ischemic Heart Failure Trial

BACKGROUND: Whether mitral valve repair during coronary artery bypass grafting (CABG) improves survival in patients with ischemic mitral regurgitation (MR) remains unknown. METHODS AND RESULTS: Patients with ejection fraction ≤35% and coronary artery disease amenable to CABG were randomized at 99 sites worldwide to medical therapy with or without CABG. The decision to treat the mitral valve during CABG was left to the surgeon. The primary end point was mortality. Of 1212 randomized patients, 435 (36%) had none/trace MR, 554 (46%) had mild MR, 181 (15%) had moderate MR, and 39 (3%) had severe MR. In the medical arm, 70 deaths (32%) occurred in patients with none/trace MR, 114 (44%) in those with mild MR, and 58 (50%) in those with moderate to severe MR. In patients with moderate to severe MR, there were 29 deaths (53%) among 55 patients randomized to CABG who did not receive mitral surgery (hazard ratio versus medical therapy, 1.20; 95% confidence interval, 0.77-1.87) and 21 deaths (43%) among 49 patients who received mitral surgery (hazard ratio versus medical therapy, 0.62; 95% confidence interval, 0.35-1.08). After adjustment for baseline prognostic variables, the hazard ratio for CABG with mitral surgery versus CABG alone was 0.41 (95% confidence interval, 0.22-0.77; P=0.006). CONCLUSION: Although these observational data suggest that adding mitral valve repair to CABG in patients with left ventricular dysfunction and moderate to severe MR may improve survival compared with CABG alone or medical therapy alone, a prospective randomized trial is necessary to confirm the validity of these observations. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00023595.