Predicting the risk of early postoperative bleeding in comorbid patients undergoing on-pump coronary artery bypass grafting

On-pump coronary artery bypass grafting (CABG) is the main method for myocardial revascularization. In comorbid patients, postoperative bleeding is 2—3 times more common and associated with higher mortality, exploration rate and transfusions. Standard clotting tests do not reflect dynamics of hemostasis in vivo, and available predictive scales have trivial discriminative ability. Objective. To develop a predictive model and an integrated risk scale for postoperative bleeding in comorbid patients after on-pump CABG according to preoperative, intraoperative and early postoperative parameters. Material and methods. A prospective cohort study included 311 patients with coronary artery disease and comorbidities. Bleeding was classified according to the Universal Definition of Perioperative Bleeding (UDPB). Laboratory monitoring included thromboelastography and standard clotting tests. Patients were divided into groups: mild/moderate bleeding (UDPB 0—2, n=274) and severe bleeding (UDPB 3, n=37). Multivariate logistic regression analysis, ROC analysis and bootstrap validation were performed. Results. The incidence of severe bleeding was 11.9%. Independent factors were body mass index (OR (odds ratio) 0.920; p=0.013), Charlson Comorbidity Index (OR 1.219; p=0.017), CPB time (OR 1.036; p=0.002), serum fibrinogen at 1 hour after surgery (OR 0.446; p<0.001), and R parameter of thromboelastography at 1 hour (OR 1.056; p=0.008). ROC analysis of predicted probability demonstrated AUC 0.818 (95% CI 0.742—0.894). At optimal cut-off with maximum Youden index (J=0.534), sensitivity was 75.7%, specificity — 77.7%. Bootstrap validation confirmed model stability (AUC 0.802). According to threshold values, a point scale (0—12 points) was developed to stratify patients into three risk categories: low (0—2 points), moderate (3—5 points), and high (6—12 points). Conclusion. Original predictive model and point scale have high discriminative ability and can be used for timely risk stratification and targeted hemostatic therapy in comorbid patients after on-pump CABG.