Introduction: Clopidogrel is a non-competitive antagonist of P2Y12, the platelet adenosine diphosphate receptor and a potent inhibitor of platelet aggregation. Clopidrogel is used in the prevention of thrombotic events in patients with recent myocardial infarction, stroke, and in patients with established peripheral arterial disease. Clopidrogel is also utilized in patients with acute coronary syndromes and those undergoing percutaneous coronary intervention. After discontinuation of the drug, recovery of platelet function takes from 7 to 14 days. The anti-platelet effect of clopidogrel is additive to that of aspirin and has shown clinical benefit in the setting of cardiovascular disease . Thus, the two agents are being administered in combination with increasing frequency. Accordingly, more patients now present for cardiac surgery on combined aspirin and clopidogrel antiplatelet therapy and this may lead to increased perioperative blood loss and transfusion requirement.
The aim of this study was to evaluate the effect of preoperative clopidogrel on bleeding and transfusion requirements after coronary artery bypass graft (CABG) surgery.
Method: We prospectively analysed 200 consecutive cardiac patients undergoing first time CABG surgery. Bleeding rates and blood ± blood product transfusion requirements in patients taking clopidogrel and aspirin were compared to those on aspirin alone. Aspirin and clopidrogel were discontinued 7 days prior to surgery as per departmental protocol. Blood loss was determined by recording maximum blood volume collected by chest drain in the 24-hour intra-operative and post-operative period.
Results: Results are reported as percentages for discrete variables and mean and standard deviation for continuous variables. Student's t-test was used to compare continuous data and Fisher's exact test for discrete data. A two-tailed P < 0.05 was considered statistically significant. Categorical data is presented as percentage.
Patient requirement for transfusion (overall transfusion rate) was significantly higher in the clopidogrel and aspirin group when compared to aspirin only.
Conclusion: The combination of clopidogrel with aspirin in patients presenting for cardiac surgery results in increased requirement for perioperative blood transfusion. There is also a trend towards increased blood loss in the peri-operative period. These findings raise concerns about continued clopidogrel administration in the immediate pre-operative period and have particular implications for patients undergoing non-emergent CABG . As our study is in effect only a pilot study it cannot make definitive recommendations, however we feel that a large multicentred clinical trial would support our research findings.
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2 Hongo RH, Ley J, Dick SE, et al. The effect of clopidogrel in combination with aspirin when given before coronary artery bypass grafting. J Am Coll Cardiol
3 Yusuf S, Mehta SR, Zhao F, et al. Early and late effects of clopidogrel in patients with acute coronary syndromes. Circulation