Effect of hypothermic versus normothermic cardiac bypass in patients undergoing coronary artery bypass grafting surgery on coagulation: a randomized controlled trial

Abstract

Objectives To assess and compare early postoperative (PO) hematological and coagulation profile of patients undergoing on-pump coronary artery bypass grafting surgery with hypothermic (HT) versus normothermic (NT) cardiopulmonary bypass. Patients and methods A total of 86 patients were divided into two equal groups: NT group included patients who received warm bypass and HT group included patients who received cold bypass. PO monitoring included changes in 2-h PO hematological and coagulation profile in relation to preoperative profile and amount of PO daily blood loss and number of transfused blood units and its relation to change in coagulation profile. Results Mean activated clotting time estimated before wound closure was significantly longer in patients of HT group. At 2-h PO, hemoglobin concentration and platelet count (PC) were significantly lower, ADP-induced platelet aggregation (IPA) was significantly decreased, whereas activated partial thromboplastin time (aPTT) and international normalized ratio (INR) were significantly increased in HT patients. Estimated activated clotting time, IPA, INR, aPTT, and PC showed a negative significant correlation with the use of HT. The amount of PO daily bleeding and number of transfused units showed a positive significant correlation with the use of HT, 2-h PO aPTT, and INR, whereas showed a negative significant correlation with 2-h PO estimated IPA and hemoglobin concentration Regression analysis and receiver operating characteristic curve analysis defined the use of HT and prolonged aPTT as significant predictors for development of PO bleeding. Conclusion On-pump coronary artery bypass grafting surgery deleteriously affects hematological and coagulation profiles of patients, and this effect was accentuated by the use of HT. Two-hour PO altered PC and function and prolonged clotting times correlated with amount of PO daily bleeding and number of transfused blood units, but prolonged aPTT is the best predictor for these events.