Postoperative blood loss in patients undergoing coronary artery bypass surgery after preoperative treatment with clopidogrel. A prospective randomised controlled study.

OBJECTIVE

The optimal timing for discontinuation of clopidogrel before surgery remains under debate. The purpose of this study is to determine the effect of preoperative clopidogrel administration on postoperative blood loss and the total requirements of homologous blood products after coronary artery bypass grafting (CABG). We also evaluated the perioperative complications.

METHODS

Consecutive patients (n=130) undergoing elective CABG were recruited and randomised between 2006 and 2007. In 38 patients (group 1), treatment with clopidogrel was discontinued 5 days prior to surgery, in 40 patients (group 2) 3 days before surgery and in 40 other patients (group 3) clopidogrel was stopped on the day of surgery.

RESULTS

Significantly more postoperative blood loss was observed in group 3 compared to group 1 (929+/-472 ml vs 664+/-312 ml; p=0.009). Other group comparisons were not significant. Blood loss after 12 h and at drain removal was also significantly higher in group 3. Patients in group 3 also had higher total requirements of homologous blood products (p=0.046) and a significantly higher need for fresh frozen plasma (FFP) transfusion (p=0.034). Univariable regression analyses revealed that continuing clopidogrel till the day of surgery (group 3) was predictive for postoperative blood loss (beta=0.289; p=0.007) and the total requirements of homologous blood products after surgery (beta=0.280; p=0.008). These effects remained the same in multivariable analyses.

CONCLUSIONS

Continuation of clopidogrel until the day of surgery induces significantly more postoperative blood loss and increases significantly the total requirements of homologous blood products and FFP transfusion after surgery. The blood loss and the use of blood products in the group that stopped at 3 days preoperatively were similar to that of the group that stopped at 5 days preoperatively.