title: Inhibition of platelet aggregation after intake of acetylsalicylic acid detected by a platelet function analyzer (PFA-100).
abstract: OBJECTIVE
  The aim of the investigation was to determine the inhibition of platelet aggregation detected by the platelet function analyzer PFA-100 in patients with coronary artery disease who routinely take 100 mg acetylsalicylic acid once daily.
  
  
  METHODS
  The PFA-100 (Dade International Inc., Miami, USA) is a new device for in vitro measurement of platelet function in citrated whole blood. The time needed to form a platelet plug occluding the aperture cut into a collagen/epinephrine- or collagen/ADP-coated membrane is determined under high shear conditions. Typically, acetylsalicylic acid-induced inhibition of platelet aggregation is detected by prolonged closure time in collagen/epinephrine or and normal values for collagen/ADP. Blood samples of 48 patients were investigated, the control group consisted of 10 healthy volunteers without intake of acetylsalicylic acid. The upper limits of normal values of the control group were 137 sec closure time for collagen/epinephrine and 150 sec for collagen/ADP (mean + 2 SD).
  
  
  RESULTS
  Statistical analysis (Wilcoxon test) did not show a significant difference (p = 0.46) between the patient group (129 +/- 11 sec) and the control group (92 +/- 7 sec) for collagen/epinephrine (mean +/- SEM). Only 31% of patients had closure time values above those upper limits defined above.
  
  
  CONCLUSIONS
  The effect of 100 mg acetylsalicylic acid daily appears to be too small and too variable to detect a sufficient inhibition of platelet aggregation by the PFA-100 in all patients with coronary artery disease.
authors.affiliation: Institute of Clinical Pharmacology, Faculty of Clinical Medicine Mannheim, University of Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Feuring
authors.forename: K
authors.initials: K
authors.lastname: Haseroth
authors.forename: C P
authors.initials: CP
authors.lastname: Janson
authors.forename: E
authors.initials: E
authors.lastname: Falkenstein
authors.forename: B M
authors.initials: BM
authors.lastname: Schmidt
authors.forename: M
authors.initials: M
authors.lastname: Wehling
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D003327:Coronary Disease / Q000097:blood / Q000188:drug therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D010979:Platelet Function Tests / Q000379:methods
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin