Abstract: Objective This study sought to evaluate the effects of preoperative continued dual antiplatelet therapy (DAPT) with aspirin and clopidogrel on early outcomes in patients undergoing off-pump coronary artery bypass grafting (OPCABG). Methods We conducted an observational cohort study of 279 patients who underwent first-time isolated OPCABG from January 2015 to May 2016 at our institution. Patients were divided into two groups, in which preoperative DAPT was given until the time of surgery (DAPT group, n = 148) or was stopped for 5 days before surgery (control group, n = 131). Baseline characteristics, total chest-tube output, rate of re-exploration for bleeding, blood-product transfusion requirements, and other perioperative and postoperative data were collected and compared. Results Demographic and preoperative clinical characteristics were similar in both groups. Total chest-tube drainage volume (DAPT group vs. control group, 899 ± 227 mL vs. 801 ± 242 mL, P = 0.001) and perioperative transfusion requirements (rate and volume) were statistically higher in the continued DAPT group compared to the control group. There were no significant differences between the groups in hemostatic re-exploration rate (DAPT group vs. control group, 3.4% vs. 0.8%, P=0.219), length of operation (DAPT group vs. control group, 4.932 ± 0.69 h vs. 4.82 ± 0.69 h， P=0.168)，ICU stay (DAPT group vs. control group, 51.82± 13.95 h vs. 50.56± 13.04 h, P=0.434), ventilation time (DAPT group vs. control group, 16.23 ± 2.57 h vs. 16.12 ± 2.61 h, P=0.729), duration of postoperative hospitalization (DAPT group vs. control group, 10.6 ± 5.4 d vs. 9.6 ± 4.8 d, P=0.108), postoperative nonfatal myocardial infarction (DAPT group vs. control group, 4.7% vs. 3.8%, P=0.708). Stroke and other severe outside chest bleeding and all-cause mortality were not observed in both groups during the postoperative period, prior to discharge. Conclusions Preoperative continued DAPT is associated with increased chest-tube drainage and higher blood-product transfusion requirements but not significant clinically. This antiplatelet strategy does not alter other investigated outcomes in primary isolated OPCABG patients. If clinically indicated, preoperative DAPT may be able to be safely continued in patients referred for primary isolated OPCABG.

Key words: off-pump, CABG, dual antiplatelet therapy, aspirin, clopidogrel.