Shear-induced platelet aggregation in aspirin-treated patients: Initial experience with the novel PlaCor PRT® device

IntroductionWhole blood platelet function testing is widely used to evaluate the effect of antiplatelet agents. Most platelet function tests employ agonists to evaluate drug-specific platelet-activating pathways. Shear-based tests may better reflect physiological conditions in vivo compared with agonist-based tests. The novel PlaCor PRT® provides a global platelet reactivity test based on shear-induced platelet aggregation. We evaluated the PlaCor PRT® and its agreement with two widely used platelet function tests.Materials and MethodsWe evaluated platelet function in 85 patients with angiographically verified coronary artery disease on aspirin mono-therapy. Blood sampling was performed one hour after aspirin ingestion. The following platelet function tests were used: PlaCor PRT®, multiple electrode aggregometry (Multiplate®, agonists: arachidonic acid 1.0 mmol/L and collagen 1.0 μg/mL) and VerifyNow® Aspirin.ResultsPlaCor PRT® results correlated significantly with multiple electrode aggregometry induced by arachidonic acid (r = − 0.38, p < 0.001), but not with multiple electrode aggregometry induced by collagen (r = − 0.05, p = 0.64) or with turbidimetric aggregometry performed with VerifyNow® Aspirin (r = − 0.13, p = 0.23). There was a strong correlation between PlaCor PRT® results and platelet count (r = − 0.60, p < 0.0001), whereas no correlation with haematocrit or von Willebrand factor antigen was found. A relatively large number of instrument errors occurred with the PlaCor PRT® device in this initial testing.ConclusionsPlaCor PRT® is a portable, rapid and user-friendly point-of-care test. It shows a modest agreement with comparable tests, and results depend considerably on platelet count. Further validation of the PlaCor PRT® is warranted.