The effect of preoperative clopidogrel on bleeding after coronary artery bypass surgery

Clopidogrel treatment is associated with a reduction in thrombotic complications in coronary stent placement, improved outcome after acute coronary syndromes, and decreased mortality in patients with coronary artery disease. The purpose of this study was to analyze the effect of preoperative clopidogrel exposure on bleeding complications, blood transfusions requirements, and reoperations in patients undergoing coronary artery bypass grafting (CABG).

This study included 320 patients from a single institution that underwent an isolated CABG who were discharged between July 2003 and June 2004. The cohort of 320 patients was classified into 3 groups. The control group consisted of 255 patients that did not receive clopidogrel or stopped clopidogrel 7 days before surgery but were treated with aspirin instead. Clopidogrel I consisted of 25 patients that were taking clopidogrel within 3 days of surgery, and Clopidogrel II consisted of 40 patients that were taking clopidogrel 4 to 7 days before surgery. Patients were compared based on preoperative data (age, gender, use of clopidogrel, preoperative hemoglobin, and ejection fraction), intraoperative data (cross-clamp time), postoperative data (chest tube output, rate of reoperation, units of transfused blood, length of stay in the intensive care unit, and length of intubation).

There were no significant differences among the 3 groups concerning age, sex, ejection fraction, or preoperative hemoglobin. There were no differences in length of intensive care unit stay and length of intubation among the 3 groups of patients. Patients in the clopidogrel I group had more units of blood transfused than either the control or the Clopidogrel II group (p=0.027). There is also a trend toward more chest tube output in clopidogrel I group compared with the control group. Fifteen patients (4.6%) of the total group required reoperation secondary to bleeding: 2 (8.0%) in the Clopidogrel I group, 2 (5%) in the clopidogrel II group, and 11 (4.3%) in the control group (p=0.41).

This study demonstrated that clopidogrel within 3 days preoperatively increases the requirement for blood transfusion in patients undergoing CABG. Waiting more than 3 days after the last dose of clopidogrel decreases blood transfusion requirements. There is also a trend toward more postoperative bleeding for those patients that took clopidogrel within 3 days before their CABG. The reoperation rate of patients that took clopidogrel within 3 days of their procedure required almost twice as many reoperations as the patients that did not take clopidogrel.