title: Tissue factor as the main activator of the coagulation system during cardiopulmonary bypass.
abstract: OBJECTIVE
  This study investigates the influence of foreign material and blood aspirated from nonvascular structures on activation of coagulation, hemolysis, and blood loss.
  
  
  METHODS
  The series comprises 3 randomized groups (groups C, S, and S+P) of 10 patients undergoing routine coronary artery bypass grafting with cardiopulmonary bypass. In group C, the control group, all aspirated blood was returned into the circulation. In group S suction blood was discarded, whereas group S+P was identical to group S, with surfaces coated with phosphorylcholine. Plasma concentrations of beta-thromboglobulin, thrombin generation, haptoglobin, and free hemoglobin, as well as blood loss, were measured.
  
  
  RESULTS
  A steady increase in free plasma hemoglobin, as well as an increased generation of thrombin, was noticed in group C. Moreover, a close correlation (r = 0.916) between the generation of thrombin and its inhibition (thrombin-antithrombin complexes) was observed. Platelets were clearly activated in group C and, to a lesser extent, in group S. In contrast, platelet activation in group S+P was negligible, resulting in a 30% decrease in blood loss (P =.05).
  
  
  CONCLUSIONS
  Aspirated blood contaminated by tissue contact is the most important activator of the coagulation system and the principal cause of hemolysis during cardiopulmonary bypass. Contact with a foreign surface is not a main variable in the procoagulant effect of bypass. Mimicking the outer cell membrane structure resulted in decreased platelet activation and decreased blood loss.
authors.affiliation: Heart Centre, University Hospital Gent, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: De Somer
authors.forename: Y
authors.initials: Y
authors.lastname: Van Belleghem
authors.forename: F
authors.initials: F
authors.lastname: Caes
authors.forename: K
authors.initials: K
authors.lastname: François
authors.forename: H
authors.initials: H
authors.lastname: Van Overbeke
authors.forename: J
authors.initials: J
authors.lastname: Arnout
authors.forename: Y
authors.initials: Y
authors.lastname: Taeymans
authors.forename: G
authors.initials: G
authors.lastname: Van Nooten
mesh_terms: D000368:Aged; D001777:Blood Coagulation / Q000502:physiology; D016063:Blood Loss, Surgical; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods*; D001026:Coronary Artery Bypass / Q000379:methods; D003327:Coronary Disease / Q000601:surgery; D005260:Female; D006242:Haptoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011300:Preoperative Care; D011446:Prospective Studies; D011516:Prothrombin / Q000032:analysis*; D012016:Reference Values; D018709:Statistics, Nonparametric; D001620:beta-Thromboglobulin / Q000032:analysis*
chemical_list: D006242:Haptoglobins; D001620:beta-Thromboglobulin; D011516:Prothrombin