Effect of clopidogrel on bleeding after coronary artery bypass surgery

Objective: Platelet dysfunction is a common cause of bleeding after coronary artery bypass graft surgery. This study explores the effects of clopidogrel on bleeding complications after coronary artery bypass graft surgery. Design: Prospective observational study of patients undergoing coronary artery bypass graft. Setting: Tertiary care center. Patients: A total of 247 patients undergoing coronary artery bypass graft surgery. Interventions: None. Measurements: Primary end point was need for reexploration secondary to bleeding. Secondary end points included need for transfusion of blood products and chest tube output. Main results: Eight (3.3%) of 247 patients required reexploration secondary to bleeding. Clopidogrel recipients had higher incidence of reexploration for bleeding (9.8 vs. 1.6, p = .01) with an odds ratio of 6.9 (95% confidence interval, 1.6-30). Clopidogrel also increased the percentage of patients receiving packed red blood cell transfusion (72.6 vs. 51.6%, p = .007), the number of packed red blood cell units (3 vs. 1.6, p =0.0004), and the number of cryoprecipitate units (2.4 vs. 1.2, p = .04) transfused after coronary artery bypass graft surgery. Among clopidogrel recipients, a trend for increased transfusion of platelet units (4.3 vs. 1.7, p = .05) and fresh frozen plasma units (1.1 vs. 0.6, p = .08) also was found. Conclusions: Preoperative use of clopidogrel in combination with aspirin is associated with increased need for surgical reexploration as well as risk of packed red blood cell and cryoprecipitate transfusions after coronary artery bypass graft surgery.