The Effect of Preoperative Epicardial Adipose Tissue Thickness on Postoperative Morbidity and Mortality in Patients Undergoing Isolated Coronary Artery Bypass Grafting

Background and Objective: Despite advances in operative techniques and perioperative care, complications following coronary artery bypass grafting (CABG) remain an important cause of postoperative morbidity and organ dysfunction. This study aimed to evaluate the association between preoperative epicardial adipose tissue (EAT) thickness measured using computed tomography and postoperative morbidity and mortality in patients undergoing isolated CABG, and to explore whether EAT thickness may serve as a potential imaging-based risk marker for postoperative complications. Materials and Methods: The study was a retrospective single-center observational cohort study. Patients who underwent isolated coronary artery bypass grafting between 1 January 2019 and 2 January 2023, and had available preoperative computed tomography (CT) imaging were retrospectively reviewed. Epicardial adipose tissue thickness was measured on CT images at three predefined anatomical regions, yielding two parameters: total EAT thickness and right ventricular EAT thickness. Postoperative complications were evaluated using established definitions, with atrial fibrillation (AF) assessed according to European Society of Cardiology (ESC) criteria and acute kidney injury defined based on Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Results: Patients who developed postoperative complications after coronary artery bypass grafting tended to have thicker epicardial adipose tissue. Increased total epicardial adipose tissue thickness was associated with postoperative paroxysmal atrial fibrillation, whereas greater right ventricular epicardial adipose tissue thickness was associated with postoperative acute kidney injury. Multivariable analysis confirmed that both total and right ventricular epicardial adipose tissue thickness were independently associated with postoperative complications (total EAT: OR 1.74, 95% CI 1.10–2.76; right ventricular EAT: OR 2.03, 95% CI 1.31–3.15). ROC analysis showed modest discrimination for postoperative atrial fibrillation (AUC 0.69) and acceptable discrimination for acute kidney injury (AUC 0.79). No association was observed between epicardial adipose tissue measurements and postoperative mortality. Conclusions: Increased preoperative epicardial adipose tissue thickness was associated with several early postoperative complications following coronary artery bypass grafting, including atrial fibrillation, acute kidney injury, and in-hospital infection. Preoperative epicardial adipose tissue thickness measured by computed tomography may represent a potentially useful imaging-based risk marker for early postoperative complications following isolated CABG, although confirmation in larger prospective studies is required.