Impact of aspirin with or without clopidogrel on postoperative bleeding and blood transfusion in coronary surgical patients treated prophylactically with a low-dose of aprotinin

AIMS: Aspirin combined with clopidogrel is the treatment of choice for acute coronary syndromes. Although the maintenance of aspirin until surgery does not affect postoperative bleeding after coronary artery bypass graft (CABG) surgery, the latter may be dramatically increased when clopidogrel is continued over a period of 5 days preoperatively. METHODS AND RESULTS: This prospective observational study included 217 consecutive patients scheduled for first-time CABG. Postoperative bleeding and blood transfusion requirements were compared (equivalence) between patients pretreated during a period of 5 days prior surgery by either aspirin alone (n = 157) or combined with clopidogrel (n = 60). Aprotinin was systematically used in all these patients considered as high risk for bleeding. We found no significant difference between both groups concerning the preoperative characteristics except for unstable angina (33 vs. 19%, P = 0.02) and left main coronary artery stenosis (27 vs. 13%, P = 0.02), which were more frequent in patients receiving clopidogrel. The median chest tube output was similar in both groups 24 h postoperatively at 350 mL (95% CI 150-850) vs. 375 mL (95% CI 175-875), and the difference between groups (7%, 95% CI -9 to 22) did not encompass the predetermined margins of equivalence (25%). No significant difference was found on blood transfusion use (38 vs. 38%, P = 0.99). After adjustment by a propensity score, we found that clopidogrel was not associated with an increased risk of excessive bleeding. CONCLUSION: In patients undergoing first-time CABG and treated prophylactically with aprotinin, aspirin and clopidogrel may be continued until surgery without increasing postoperative bleeding or transfusion requirements.