Bleeding post coronary artery bypass surgery: Clopidogrel-Cure or culprit?

ABSTRACT

Clopidogrel, in addition to aspirin, has become a common treatment of acute coronary syndrome and for stent thrombosis prevetion, when given before precutaneous transluminal coronary angioplasty. However, some patients turn out to have surgical coronary artery disease and are sent for coronary artery bypass grafting [CABG] where the irreversible effect of aspirin and clopidogrel on platelet function becomes a concern. This study was conducted to evaluate the role of preoperrative use of clopidogrel in bleeding complications after CABG. A total of 462 patients who underwent CABG between 2001 and 2003 were studied as a retrospective cohort. Comparison was made between patients who had taken clopidogoral within 7 days of surgery [n=162], and those who were not exposed to clopidogeral [n=300]. Chest tube output and bleeding index [a modified TIMI criteria], were primary outcomes measured. Our data showed that patients taking clopidogrel within 7 days of surgery have a higher bleeding index than those who were not exposed to the drug [p=0.024]. Similarlly, chest tube output was significantly higher in those who were exposed to clopidogrel within 7 days compared to those not taking clopidogrel [p=0.01]. To further dissect this rela tionship, we divided our population into three categories. We found that patients taking clopidogrel within 3 days prior to CABG [immediate exposure] have a higher bleeding index and TIMI major bleeding than either patients taking the drug between 3 and 7 days [recent exposure] or patients not exposed to clopidogrel at all [p=0.009] and 0.03 respectively for inter-groups comparsion]. The same was true for chest tube output [p=0.05 and 0.01 respectively]. Clopidogrel increased the risk of post-CABG bleeding if taken within three days prior to surgery but not if taken before that