title: Preoperative platelet aggregation predicts perioperative blood loss and rethoracotomy for bleeding in patients receiving dual antiplatelet treatment prior to coronary surgery.
abstract: BACKGROUND
  Patients scheduled for coronary artery bypass graft surgery (CABG) are commonly treated with clopidogrel. We sought to assess the relation between preoperative platelet aggregation and bleeds in CABG patients on clopidogrel.
  
  
  METHODS
  In a case-control study, we compared 52 consecutive patients undergoing isolated CABG on aspirin and clopidogrel 75mg/d versus 50 controls on aspirin monotherapy. Platelet aggregation induced by 10μmol/l adenosine di-phosphate (ADP) in platelet-rich plasma was measured in subjects on clopidogrel within 5days prior to surgery. ADP-induced aggregation of ≥50% was used to define subjects with satisfactory inhibition of platelet reactivity.
  
  
  RESULTS
  In 29 patients with preoperative ADP-induced aggregation ≥50%, compared with 23 subjects with aggregation <50%, lower chest-tube drainage volumes (after 6h, p=0.002; and 12h, p=0.001) and fewer rethoracotomies were observed (p=0.03). The former group was characterized with lower transfusion rates of packed red blood cells (p=0.009), platelet concentrate (p=0.04) and fresh frozen plasma (p=0.001). Patients with ADP-induced aggregation ≥50% did not differ from untreated controls regarding the postoperative drainage, transfusions and rethoracotomy. The incidence of thromboembolic events and death during perioperative period were similar in all groups. Multivariate logistic regression identified ADP-induced aggregation <50% as the only independent predictor of rethoracotomy (OR=2.94 [1.12-7.75], p=0.029).
  
  
  CONCLUSIONS
  Patients on aspirin and clopidogrel <5days before CABG who had preoperative ADP-induced platelet aggregation ≥50% have bleeding risk similar to those receiving aspirin monotherapy. Reduced platelet reactivity to ADP can predict postoperative bleeding in CABG patients on dual antiplatelet therapy.
authors.affiliation: John Paul II Hospital, Krakow, Poland.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Plicner
authors.affiliation: John Paul II Hospital, Krakow, Poland; Institute of Cardiology, Jagiellonian University Medical College, Krakow, Poland. Electronic address: piotr.k.mazur@gmail.com.
authors.forename: Piotr
authors.initials: P
authors.lastname: Mazur
authors.affiliation: John Paul II Hospital, Krakow, Poland.
authors.forename: Hubert
authors.initials: H
authors.lastname: Hymczak
authors.affiliation: John Paul II Hospital, Krakow, Poland.
authors.forename: Jarosław
authors.initials: J
authors.lastname: Stoliński
authors.affiliation: John Paul II Hospital, Krakow, Poland; Institute of Cardiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Radosław
authors.initials: R
authors.lastname: Litwinowicz
authors.affiliation: John Paul II Hospital, Krakow, Poland; Institute of Cardiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Drwiła
authors.affiliation: John Paul II Hospital, Krakow, Poland; Institute of Cardiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Anetta
authors.initials: A
authors.lastname: Undas
mesh_terms: D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects*; D016063:Blood Loss, Surgical / Q000517:prevention & control; D000077144:Clopidogrel; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects; D010979:Platelet Function Tests / Q000379:methods*; D019106:Postoperative Hemorrhage / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control; D011292:Premedication / Q000009:adverse effects; D011379:Prognosis; D012086:Reoperation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013903:Thoracic Surgery; D013927:Thrombosis / Q000517:prevention & control*; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D016896:Treatment Outcome
chemical_list: D004338:Drug Combinations; D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Bleeding; CABG; Clopidogrel; Coronary artery bypass grafting; Platelet aggregation; Transfusions