Clopidogrel treatment before coronary artery bypass graft surgery increases postoperative morbidity and blood product requirements.

OBJECTIVES: An increasing number of patients are referred for coronary artery bypass graft surgery while treated with clopidogrel. This agent inhibits the platelet P2Y12 adenosine-5'-diphosphate (ADP) receptor, which results in an inhibition of platelet aggregation. The aim of this study was to determine the effect of preoperative clopidogrel treatment on postoperative bleeding, mortality, and morbidity in patients after coronary artery bypass graft surgery.

DESIGN: Retrospective cohort study.

SETTING: University hospital (single institution).

PARTICIPANTS: One hundred forty-four patients who underwent isolated coronary artery bypass graft surgery.

INTERVENTIONS: Seventy-two patients who received clopidogrel during the preoperative period formed the study group. Seventy-two patients (matched based on age, sex, and preoperative risk profile) served as the control group.

MEASUREMENTS AND MAIN RESULTS: Clopidogrel-treated patients received significantly more platelet (4.4 +/- 5.7 v 1.3 +/- 3.2 U, p < 0.001) and red blood cell (5.1 +/- 4.2 v 2.6 +/- 2.6 U, p < 0.001) transfusions compared with the control group. All-cause mortality and morbidity were significantly higher in clopidogrel-treated patients (n = 7, 9% v n = 1, 1%; p = 0.031). In addition, the lengths of stay in the intensive care unit and the hospital were significantly longer in these patients (2.5 +/- 2.7 v 1.4 +/- 0.9 days, p = 0.002; 9.9 +/- 11 v 6 +/- 2.5 days, p = 0.003). Despite an increased morbidity in the clopidogrel group, the midterm survival was similar between the 2 groups (1-year and 5-year survival 97% +/- 2% and 95.7% +/- 3% v 100% +/- 0% and 87% +/- 10%, respectively; p = 0.885).

CONCLUSIONS: Preoperative clopidogrel is associated with increased transfusion requirement after coronary artery bypass graft surgery. The present data suggest that all-cause mortality and major morbidity may also increase in these patients. In clopidogrel-treated patients, coronary artery bypass graft surgery should be delayed in the absence of specific medical indications as recommended by recent American Heart Association guidelines.