title: Clopidogrel increases blood transfusion and hemorrhagic complications in patients undergoing cardiac surgery.
abstract: BACKGROUND
  Utilization of the irreversible antiplatelet agent clopidogrel is increasing in the treatment acute coronary syndrome patients. Consequently, more patients are presenting for urgent cardiac surgery with an irreversible defect in platelet function. The objective of this study was to determine whether recent clopidogrel administration predicts transfusion and hemorrhagic complication in cardiac surgery patients.
  
  
  METHODS
  This retrospective study included all patients undergoing isolated coronary artery bypass graft surgery (CABG), isolated valve, or CABG plus valve at a single center between 2004 and 2008. The outcomes of interest were transfusion and hemorrhagic complication. Clopidogrel stop interval was defined as the time between last dose and presentation to the operating room, and was examined in daily increments from 0 to 5 days, more than 5 days, and not receiving clopidogrel preoperatively. By logistic regression, the association of clopidogrel stop interval with transfusion and with hemorrhagic complication was examined after adjusting for other risk factors.
  
  
  RESULTS
  Of 3,779 patients included in this study, 26.4% (999) received clopidogrel preoperatively. The overall rates of transfusion and hemorrhagic complication were 34.1% and 4.1%, respectively. Clopidogrel use within 24 hours was an independent predictor of transfusion (odds ratio 2.4; 95% confidence interval: 1.8 to 3.3) and of hemorrhagic complication (odds ratio 2.1; 95% confidence interval: 1.3 to 3.6).
  
  
  CONCLUSIONS
  Patients receiving clopidogrel within 24 hours of surgery are at increased risk for transfusion and hemorrhagic complication. Timing of surgery for patients receiving clopidogrel should take into account the interval from the last dose.
authors.affiliation: Division of Cardiac Surgery, Queen Elizabeth II Health Sciences Center, Halifax, Nova Scotia, Canada.
authors.forename: Christine R
authors.initials: CR
authors.lastname: Herman
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Buth
authors.forename: Blaine A
authors.initials: BA
authors.lastname: Kent
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Hirsch
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001803:Blood Transfusion; D002315:Cardiopulmonary Bypass; D000077144:Clopidogrel; D001026:Coronary Artery Bypass; D047549:Coronary Artery Bypass, Off-Pump; D004334:Drug Administration Schedule; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*; D019106:Postoperative Hemorrhage / Q000139:chemically induced* / Q000628:therapy; D011300:Preoperative Care; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine