Meta-Analysis of Usefulness of Concomitant Mitral Valve Repair or Replacement for Moderate Ischemic Mitral Regurgitation With Coronary Artery Bypass Grafting

Moderate ischemic mitral regurgitation (MR) is often present in patients undergoing coronary artery bypass grafting (CABG). However, the clinical benefit of repairing moderate MR during CABG is unproven. We searched multiple databases to identify original studies comparing isolated CABG versus combined CABG and MR surgery (mitral valve surgery with coronary artery bypass grafting [MVCABG]); survival (either early or midterm) was the primary end point. Risk ratio (RR) or standardize mean difference was selected as the effect estimates; survival was compared by pooling hazard ratios. All results are presented with 95% CIs; p <0.05 is statistically significant. Eleven studies (7 retrospective and 4 randomized controlled trials; 547 MVCABG and 900 CABG patients) were included in our meta-analysis. Concomitant mitral valve repair significantly prolonged surgical duration (p <0.01). Early mortality (MVCABG 6.9% and CABG 6%) was comparable (RR 1.3 [0.9 to 1.8]; p = 0.11). At follow-up, the MVCABG patients had similar New York Heart Association class (standardize mean difference -0.73 (-1.64 to 0.18; p = 0.11). However, patients who underwent concomitant mitral valve surgery had less MR at follow-up (recurrent significant MR, RR 0.37 [0.22 to 0.62]; p = 0.001; mean MR grade, mean difference = 0.39 [0.26 to 0.59]; p <0.001). Midterm survival rate (mean follow-up 5 years) was comparable in both groups (hazard ratio for mortality in the MVCABG cohort 1.1 [0.9 to 1.3]; p = 0.38). In conclusion, concomitant repair of moderate ischemic MR leads to improved mitral valve competence at follow-up; however, this was not translated into any functional or survival benefit for adding valve repair to CABG for these patients at 5 years of follow-up.