Differential Impact of Mitral Valve Repair on Outcome of Coronary Artery Bypass Grafting with or without Surgical Ventricular Reconstruction in the Surgical Treatment for Ischemic Heart Failure (STICH) Trial

Background: This study examined the impact of mitral valve repair (MVRe) on survival of patients with moderate or severe (≥2+) MR and ischemic cardiomyopathy randomized to coronary artery bypass grafting (CABG) versus CABG+surgical ventricular reconstruction (SVR) in the STICH trial. Methods: Among patients with moderate or severe MR and ischemic cardiomyopathy undergoing CABG or CABG+SVR, the impact of MVRe on mortality between the two treatment arms was compared. Results: Among 867 patients with assessment of baseline MR severity, 211 had moderate or severe MR. After excluding 7 patients who underwent mitral valve replacement, 50, 44, 62, and 48 patients underwent CABG, CABG+MVRe, CABG+SVR, and CABG+SVR+MVRe, respectively. Four-year mortality rates were lower following CABG+MVRe than CABG alone (16% vs. 55%; adjusted hazard ratio [HR] 0.30; 95% CI 0.13–0.71). In contrast, the CABG+SVR+MVRe and CABG+SVR groups had similar 4-year mortality of 39% vs. 39% (adjusted HR 0.88; 95% CI 0.46–1.70). MVRe had a more favorable effect on survival in patients undergoing CABG alone compared to CABG+SVR (p = 0.013). Baseline MR severity was similar between patients that received CABG+MVRe and those that underwent CABG+SVR+MVRe. A larger proportion of patients demonstrated a reduction in MR between 4 and 24 months after CABG+MVRe compared to CABG+SVR+MVRe (50.0% versus 25.0%, p = 0.023). Conclusion: In patients with moderate or severe MR and ischemic cardiomyopathy undergoing CABG, MVRe appears to have a favorable effect on survival. The addition of SVR to CABG may attenuate the anticipated benefits of MVRe by limiting the long-term reduction of MR with MVRe.