title: Functional evaluation of platelet aspirin resistance after on-pump coronary bypass grafting using multiple aggregation tests.
abstract: OBJECTIVE
  The predominant mechanism of early graft failure after coronary artery bypass grafting (CABG) is associated with antiplatelet treatment using drugs such as acetylsalicylic acid (ASA). Impaired hemostasis of multiple etiologies is often present in patients undergoing on-pump cardiac surgery. We investigated the impact of intravenous ASA administration on platelet function in this setting.
  
  
  METHODS
  Forty-two patients were enrolled in the study. Patients received 100 mg oral ASA once daily, beginning in the early postoperative period. Noncompliance was eliminated by the administration of 300 mg ASA intravenously at 6-8 days post-operation. Blood was drawn immediately before, 1 h and 24 h after ASA administration.
  
  
  RESULTS
  A platelet function analyzer (PFA-100™) was used to evaluate closure time (CT), turbidimetric platelet aggregation (TPA) and impedance platelet aggregation (IPA) induced by arachidonic acid (AA), collagen and ADP and results were compared with the respective values from 120 healthy individuals. At 1 h and 24 h after administration, we found that intravenous ASA caused CEPI-CT to be significantly prolonged with a reduction of AA and collagen-induced IPA. Despite postoperative oral ASA administration for 6-8 days, PFA-100™ CEPI and CADP-CT were significantly shorter and ADP-TPA and IPA values induced by any agonist were significantly greater in patients than in controls. Intravenous ASA had no significant influence on CADP-CT or ADP-induced IPA (ADP-IPA).
  
  
  CONCLUSIONS
  Platelet tests for diagnosing patients as aspirin responders (ASA-R) or aspirin non-responders (ASA-NR) were found to be not comparable. Patients after CABG show augmented platelet dysfunction. Intravenous ASA administration may indicate a promising approach to reduce laboratory resistance after CABG procedure. The reason for this is not clear and requires additional clinical studies.
authors: Department of Cardiac Surgery, Academic City Hospital Ludwigshafen, Ludwigshafen, Germany. kammerei@klilu.de
authors: I
authors: I
authors: Kammerer
authors: J
authors: J
authors: Bach
authors: W
authors: W
authors: Saggau
authors: F
authors: F
authors: Isgro
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000008:administration & dosage*; D016022:Case-Control Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects; D004351:Drug Resistance; D005260:Female; D005858:Germany; D006801:Humans; D007275:Injections, Intravenous; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D010979:Platelet Function Tests; D011237:Predictive Value of Tests; D013927:Thrombosis / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin