title: A novel method to assess platelet inhibition by eptifibatide with thrombelastograph.
abstract: We examined a novel method to detect platelet inhibition with thrombelastography (TEG). We hypothesized that this method would be suitable for monitoring the antiplatelet effects of eptifibatide (Integrilin). Whole blood from healthy volunteers was anticoagulated with 3.2% citrate or unfractionated heparin (7 IU/mL). For the platelet aggregation test, both citrate and heparinized samples were spiked with increasing concentrations of eptifibatide (0, 0.2, 0.4, 0.8, 1.6, and 4 microg/mL). Conventional kaolin TEG was performed with citrated samples, and batroxobin-modified TEG was performed with heparinized samples, which were spiked with eptifibatide at concentrations of 0, 0.4, 0.8, 1.6, 4, 8, and 24 microg/mL. Adenosine 5'-diphosphate-induced platelet aggregation was reduced to 6.4% +/- 2.9% (citrate) and 10.3% +/- 4.8% (heparin) with eptifibatide at the concentration of 4 mug/mL. The kaolin TEG showed a decrease in maximum amplitude (MA) only at the eptifibatide concentration of 24 mug/mL and no change in alpha angle, whereas with the batroxobin-based TEG, the difference in MA and alpha angle was observed at concentrations >/=0.8 microg/mL. Additionally, the time to achieve maximum MA was much shorter for batroxobin TEG than for kaolin TEG. We conclude that the batroxobin-modified TEG is a sensitive method that detects platelet inhibition induced by eptifibatide.
authors.affiliation: Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Katori
authors.forename: Fania
authors.initials: F
authors.lastname: Szlam
authors.forename: Jerrold H
authors.initials: JH
authors.lastname: Levy
authors.forename: Kenichi A
authors.initials: KA
authors.lastname: Tanaka
mesh_terms: D000244:Adenosine Diphosphate; D000925:Anticoagulants / Q000494:pharmacology; D012103:Batroxobin; D001809:Blood Viscosity; D004305:Dose-Response Relationship, Drug; D000077542:Eptifibatide; D005343:Fibrinolytic Agents; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007616:Kaolin; D010455:Peptides / Q000494:pharmacology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D010976:Platelet Count; D013916:Thrombelastography
chemical_list: D000925:Anticoagulants; D005343:Fibrinolytic Agents; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D007616:Kaolin; D000244:Adenosine Diphosphate; D006493:Heparin; D012103:Batroxobin; D000077542:Eptifibatide