Should moderate ischemic mitral regurgitation be corrected during coronary artery bypass grafting? a systematic review and meta‐analysis

Ischemic mitral regurgitation (IMR) is associated with increased risks of mortality and heart failure. However, the optimal management of moderate IMR remains controversial. We conducted a meta-analysis to appraise whether moderate IMR should be corrected during coronary artery bypass grafting (CABG). We searched PubMed, Embase, and Cochrane databases from its inception up to 15 October 2022 for studies that assessed CABG alone versus CABG with mitral valve (MV) surgery in patients with moderate IMR. The primary outcome was perioperative mortality. Four randomized controlled trials and three observational studies with propensity-matched data including 1209 patients assessing CABG alone ( n = 598) versus CABG with MV surgery ( n = 611) were included. Compared to CABG alone, the addition of MV surgery did not significantly increase perioperative mortality (RR, 1.01; 95% CI, 0.52–1.96; p = 0.98) and stroke (RR, 2.14; 95% CI, 0.97–4.72; p = 0.06), whereas a longer cardiopulmonary bypass duration (MD, 54.91; 95% CI, 42.13–67.68; p < 0.01) and an increased incidence of renal failure were observed in the combined-procedure group. At follow-up, the addition of MV surgery was significantly associated with reduced rates of residual MR (RR, 0.26; 95% CI, 0.13–0.51; p < 0.01) and NYHA class III-IV (RR, 0.54; 95% CI, 0.37–0.78; p < 0.01). However, there was no difference in either mid-term mortality (RR, 1.05; 95% CI, 0.65–1.70; p = 0.82) or late mortality (RR, 91; 95% CI, 0.49–1.71; p = 0.78) between the CABG alone group and the combined-procedure group. In patients with moderate IMR, the addition of MV surgery to CABG did not increase perioperative mortality. Despite the reduced rates of moderate MR and NYHA class III-IV at follow-up, the addition of MV surgery did not translate in a reduction in mid-term or late mortality.