Objective To assess whether the dual antiplatelet therapy with aspirin and clopidogrel affects operative bleeding complications in elderly patients (over 65 years of age) to be treated by off-pump coronary artery bypass grafting (OPCABG).Methods Retrospective analysis of related clinical data from 276 patients (65-83 years of age)receiving OPCABG was performed.The patients were divided into 2 groups according to the type of antiplatelet therapy:216 cases were given both clopidogrel and aspirin (group AC),while 60 cases were given aspirin alone (group A).Preoperative basic clinical information,intraoperative and postoperative general data were compared between the two groups,and intraoperative bleeding volume,postoperative pleural drainage volume and consumption of blood products were recorded.Using multiple linear regression model,the factors influencing intraoperative blood loss were further analyzed.Results The average age of group AC was younger than that of group A.The platelet count of group AC was less than group A,and each result of blood coagulation test in group AC was slightly shorter than that in group A.However,that of platelet count and blood coagulation test results were in normal range.Other factors had no statistical difference (P>0.05).The two groups of patients had no serious complications and operative mortality.Compared with group A,the consumption of plasma (P=0.000) during operation was less in group AC,but the platelet consumption in surgery is more (P=0.013).There was no statistical difference in the operative time,number of transplant blood vessels,intraoperative blood loss,and consumption of red blood cells between the two groups.Postoperatively,the total time of chest drainage in group AC was longer than that in group A (P=0.002),but the mean postoperative hospital stay was shorter (P=0.005).There was no statistical difference in the postoperative mechanical ventilation time,consumption of red blood cells,plasma and platelet during the first 24 h after surgery,volume of chest drainage during the first 24 h after surgery,postoperative consumption of plasma and platelet,total volume of postoperative chest drainage and postoperative ICU stay time between the two groups (P>0.05).Combined multiple linear enter regression and stepwise regression model revealed that the type of anti-platelet therapy had no significant correlation to intraoperative blood loss (r=-0.044,P=0.996).And the operative time were slightly related to intraoperative blood loss (r=0.262,P=0.000).Conclusion In patients over 65 years of age to undergo OPCABG,preoperative dual antiplatelet therapy with combined aspirin and clopidogrel does not increase intraoperative blood loss,volume of postoperative drainage and consumption of postoperative blood products,compared to aspirin therapy alone.Also,the dual antiplatelet therapy does not increase the risk of operative bleeding complications.