title: Response to aspirin in healthy individuals. Cross-comparison of light transmission aggregometry, VerifyNow system, platelet count drop, thromboelastography (TEG) and urinary 11-dehydrothromboxane B(2).
abstract: Variable biological effect of aspirin is suggested to be related to pharmacological resistance. The incidence of this so-called "resistant" state varies with the study population and the assay used. We determined performance features of five assays used to assess aspirin effects in non-smoking healthy volunteers not taking any drug known to interfere with platelet function. Blood and urine samples were obtained immediately before and after 8-10 days of aspirin 80 mg intake. Forty-five participants 19-59 years old were enrolled. The sensitivity (SE), specificity (SP), and optimal cut-off (CO) value to detect the effect of aspirin were: light transmission aggregometry (LTA) with 1.6 mM arachidonic acid (AA) - SE 100%, SP 95.9%, CO 20%; LTA with adenosine diphosphate (ADP) 10 microM - SE 84.4%, SP 77.8%, CO 70%; VerifyNow Aspirin - SE 100%, SP 95.6%, CO 550 ARU; platelet count drop - SE 82.2%, SP 86,7%, CO 55%; TEG((R)) - SE 82,9%, SP 75,8%, CO 90%; and urinary 11-dehydrothromboxane B(2) levels (11-dHTB(2)) - SE 62.2%, SP 82.2%, CO 60 pg/ml. AA-induced LTA and the VerifyNow assay reliably detected aspirin intake in all subjects; there was wide overlap in pre- and post- aspirin results with ADP-induced LTA, platelet count drop, TEG((R)) and urinary 11-dHTB(2) assays. These results suggest that some of the variability in the reported incidence of "aspirin resistance" is unrelated to aspirin intake but related to inherent limitations of some assays to detect aspirin mediated effects or to underlying platelet reactivity variability independent of aspirin-mediated cyclooxygenase-1 inhibition.
authors: CHUM - Hôpital Notre-Dame, 6ième étage, Pavillon Deschamps, Montréal, Canada. n.blais@umontreal.ca
authors: Normand
authors: N
authors: Blais
authors: Chantal
authors: C
authors: Pharand
authors: Marie
authors: M
authors: Lordkipanidzé
authors: Ying K
authors: YK
authors: Sia
authors: Yahye
authors: Y
authors: Merhi
authors: Jean G
authors: JG
authors: Diodati
mesh_terms: D000328:Adult; D001241:Aspirin / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D010976:Platelet Count; D010979:Platelet Function Tests / Q000379:methods* / Q000706:statistics & numerical data; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013916:Thrombelastography; D013929:Thromboxane B2 / Q000031:analogs & derivatives / Q000652:urine; D055815:Young Adult
chemical_list: D010975:Platelet Aggregation Inhibitors; D013929:Thromboxane B2; C049235:11-dehydro-thromboxane B2; D001241:Aspirin