Coronary Artery Bypass Grafting Versus Combined Coronary Artery Bypass Grafting and Mitral Valve Repair in Treating Ischaemic Mitral Regurgitation: A Meta-analysis

Background Ischaemic mitral regurgitation (IMR) is commonly manifested after coronary artery disease, but it is still controversial as to whether coronary artery bypass grafting (CABG) alone improves postoperative outcome. Objectives A focussed clinical question was designed and a meta-analysis of published studies was performed to identify the impact of mitral valve repair (MVR) in patients with IMR undergoing CABG versus those undergoing CABG alone. Methods Using the Medline database, the Cochrane clinical trials database and online clinical trial databases, we reviewed all RCTs and observational studies examining the impact of MVR and CABG in treating patients with IMR. We searched for literature published before September 2013 and earlier. Results This analysis identified five studies which examined the impact of CABG alone versus combined CABG and MVR in treating patients with IMR, involving 1038 patients, with 423 patients undergoing CABG alone and 615 were performed combined CABG and MVR procedures. There was significant improvement in postoperative mitral regurgitation (MR) grade in combined group, comparing with CABG alone group (WMD: 1.34, 95% CI: 0.47 to 2.21, p = 0.003), but no significant differences were noted between the CABG plus MVR group and CABG alone group in terms of in-hospital mortality (OR: 0.84, 95% CI: 0.44 to 1.61, p = 0.60), MR grade improvement rate (OR: 0.19, 95% CI: 0.02 to 1.66, p = 0.13), postoperative mean NYHA functional class (WMD: 0.33, 95% CI: -0.29 to 0.94, p = 0.30) and five-year survival (OR: 0.77, 95% CI: 0.34 to 1.73, p = 0.53). Conclusions Compared with CABG alone, patients who underwent combined CABG and MVR procedures showed a greater improvement in postoperative MR grade, but in terms of in-hospital mortality, MR grade improvement rate, postoperative mean NYHA functional class and five-year survival, adding MVR to CABG surgery lacks evidence to show its superiority.