Changes and predictors of secondary mild mitral regurgitation after coronary artery bypass grafting

Background: Secondary mitral regurgitation (SMR) has been related to left ventricular (LV) remodeling and geometric deformation of the mitral apparatus after myocardial infarction (MI), and proved to be associated with adverse cardiac events. We assessed the proportion of mild SMR before and after isolated coronary artery bypass grafting (CABG) surgery, and further study to evaluate dynamic changes of MR and the determinants of such process on 1 year follow-up. Methods: From 2019 to 2021, cohort study of 171 consecutive hospitalized patients who underwent selective isolated CABG surgery were included and divided into the control group and mild MR group according to whether mild MR occurred at baseline. Univariate analysis and multivariate logistic regression analysis were used to test the associations of changes in MR after CABG, and p < 0.05 was considered significant. Results: The mean age of the cohort was 61.31 +/- 8.71 years and 78.95% were male at baseline, divided into the control group (74.85%) and mild MR group (25.15%), respectively. The LV volumetric and size parameters were higher in the mild MR group, with decline in LV and left atrial (LA) strain measurements. About half participants with mild MR at baseline persisted in that category and the rest reverted to none MR on follow-up, while preoperative left main coronary artery occlusion may impede the improvement (p < 0.05). The control group at baseline tended to maintain none MR and one-eighth progressed to mild MR on follow-up, moreover older age and lower LVEF emerged as key correlation of this development. LA volume index (LAVi) was associated with an increased risk of developing mild MR (p < 0.05). Conclusions: Patients with secondary mild MR had LA dysfunction and CABG surgery promoted regression of MR. LAV has an incremental role for early detection of change in MR over time after surgery.