A novel method to assess platelet inhibition by eptifibatide with thrombelaistograph®

We examined a novel method to detect platelet inhibition with thrombelastography (TEG(R)). 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 mug/mL). Conventional kaolin TEG(R) was performed with citrated samples, and batroxobin-modified TEG(R) was performed with heparinized samples, which were spiked with eptifibatide at concentrations of 0, 0.4, 0.8, 1.6, 4, 8, and 24 mug/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(R) showed a decrease in maximum amplitude (MA) only at the eptifibatide concentration of 24 mug/mL and no change in a angle, whereas with the batroxobin-based TEG(R), the difference in MA and alpha angle was observed at concentrations greater than or equal to0.8 mug/mL. Additionally, the time to achieve maximum MA was much shorter for batroxobin TEG(R) than for kaolin TEG(R). We conclude that the batroxobin-modified TEG(R) is a sensitive method that detects platelet inhibition induced by eptifibatide.