Multimodal Imaging Analysis and Early Outcomes of Coronary Artery Bypass Grafting in Patients with Different Ejection Fraction

Objective : To investigate the value of multimodal imaging in evaluating early postoperative outcomes in coronary artery disease (CAD) patients with different left ventricular ejection fraction (LVEF) undergoing coronary artery bypass grafting (CABG). Methods : A total of 192 patients undergoing CABG were enrolled and divided into three groups based on LVEF: normal (≥51%), reduced cardiac function(46%-50%), and low-ejection fraction groups (≤45%). Coronary computed tomography angiography (CCTA) was used to assess graft patency, and stress cardiac magnetic resonance (CMR) was performed to evaluate cardiac function, myocardial blood flow (MBF), and myocardial flow reserve (MFR) preoperatively and 6 months follow-up. Clinical characteristics, surgical risks, and imaging parameters were compared among groups. Results : The reduced LVEF group had significantly higher rates of intra-aortic balloon pump use (30.6%), unplanned conversion to cardiopulmonary bypass (13.9%), and early graft failure (25.9%) compared to the normal group ( P <0.05). Postoperatively, the low-ejection fraction group showed significant improvements in LVEF, reductions in left ventricular size and end-diastolic volume, and enhanced myocardial perfusion. However, 30-day mortality (5.6%) occurred only in this group. Multivariate analysis identified preoperative MFR in the left anterior descending artery territory (β=0.445) and NT-proBNP (β=-0.202) as independent determinants of preoperative LVEF (R²=0.552). Conclusion : Patients in both reduced cardiac function and low-ejection fraction groups achieve significant early improvements in cardiac structure, function, and myocardial perfusion after CABG, but they also face the higher intraoperative risks and challenges to graft patency. Multimodal imaging, particularly stress CMR-derived MFR, offers valuable insights for preoperative risk assessment.