title: Modified thromboelastography evaluation of platelet dysfunction in patients undergoing coronary artery surgery.
abstract: OBJECTIVE
  Anti-platelet therapy is associated with increased perioperative bleeding. Although current guidelines call for its caessation 5-10 days prior to cardiac surgery, this could constitute an increased risk of preoperative myocardial infarction. The optimal safe period from discontinuation of anti-platelet therapy to surgery is as yet unknown for the individual patient. We investigated whether preoperative thromboelastography (TEG) with platelet mapping could predict bleeding tendency in patients (on recent anti-platelet therapy) undergoing coronary artery bypass grafting (CABG).
  
  
  METHODS
  We prospectively evaluated 59 patients on aspirin and clopidogrel therapy who underwent CABG. Of them, 25 patients received aspirin alone. TEG with platelet mapping was performed immediately prior to surgery in all 59 patients.
  
  
  RESULTS
  During the first 24h post-surgery, 9/59 patients bled excessively (1216 + or - 310 ml in excessive bleeding vs 576 + or - 155 ml in non-bleeding patients). Of the patients bled excessively, eight received clopidogrel treatment prior to surgery. However, 26 of the remaining 34 patients receiving clopidogrel did not bleed significantly. Clopidogrel-induced platelet dysfunction diagnosed by platelet mapping discerned between patients who demonstrated excessive bleeding and those who did not (78% - sensitivity, 84% - specificity, p=0.004). Aspirin-induced platelet dysfunction did not reflect a bleeding tendency. Of all patients, 85% did not respond to a standard dose of clopidogrel, whereas 44% did not respond to aspirin.
  
  
  CONCLUSIONS
  TEG with platelet mapping is able to predict excessive postoperative blood loss among patients who underwent CABG and recent anti-platelet therapy. The prevalence of non-responsiveness to anti-platelet therapy, including clopidogrel, is higher in patients undergoing coronary artery bypass grafting than in the general population. In this study, aspirin-induced platelet dysfunction did not influence postoperative blood loss.
authors.affiliation: Department of Anesthesiology and Intensive Care, Sheba Medical Center, Tel Hashomer, Ramat Gan 52621, Tel Aviv University, Sackler School of Medicine, Tel Aviv, Israel. Sergey.Preisman@sheba.health.gov.il
authors.forename: Sergey
authors.initials: S
authors.lastname: Preisman
authors.forename: Alexander
authors.initials: A
authors.lastname: Kogan
authors.forename: Kira
authors.initials: K
authors.lastname: Itzkovsky
authors.forename: Gleb
authors.initials: G
authors.lastname: Leikin
authors.forename: Ehud
authors.initials: E
authors.lastname: Raanani
mesh_terms: D000368:Aged; D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects; D001791:Blood Platelet Disorders / Q000139:chemically induced / Q000150:complications / Q000175:diagnosis*; D000077144:Clopidogrel; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D004334:Drug Administration Schedule; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*; D019106:Postoperative Hemorrhage / Q000209:etiology; D011300:Preoperative Care / Q000379:methods*; D011379:Prognosis; D013916:Thrombelastography / Q000379:methods; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin