Late outcome of coronary artery bypass grafting with or without mitral repair for moderate or moderate–severe ischemic mitral regurgitation

Background Operative indication of the additional mitral repair for moderate ischemic mitral regurgitation (MR) in the setting of coronary artery bypass grafting (CABG) is still unclear. Methods This study was designed as the nation-wide multi-center retrospective analysis with additional survival data. CABGs without past heart surgery registered in 2014 and 2015 were included. Concomitant surgery other than tricuspid or arrhythmia surgery, mitral replacement, and off-pump cases, was excluded. Grade 1 or 4 MR, and ejection fraction < 20 or > 50 were excluded. Additional questionnaire was sent to each hospital, regarding the pathology of MR and clinical outcomes. Additional data were registered between May 28, 2021 and Dec 31, 2021, and the primary outcomes were all-death and cardiac death. The secondary outcomes were heart failure and cerebrovascular event requiring admission, mitral re-intervention. Patients underwent on-pump CABG (CABG only group 221 cases) and CABG with mitral repair (CABG + Mitral repair group 276 cases) were enrolled. Results After Propensity score matching, 362 cases (CABG only 181cases vs CABG + mitral repair 181 cases) were matched. Cox regression model showed no statistical difference in the long-term survival between CABG alone group and combined procedure group ( p = 0.52). Cardiac death ( p = 1.00), heart failure ( p = 0.68), and cerebrovascular event ( p − 0.80) requiring admission were not different between groups as well. The incidence of mitral re-intervention was very few (2 cases in CABG only group, 4 cases in CABG + mitral repair group). Conclusions In patients with moderate ischemic MR, additional mitral repair to CABG did not improve long-term survival, freedom from heart failure, or cerebrovascular event.