title: PlaCor PRT measurement of shear-activated platelet aggregate formation in stable patients treated with single and dual antiplatelet therapy.
abstract: Shear forces play a key role in thrombus formation and shear-based tests may better reflect physiological conditions in vivo compared with agonist-based tests. We evaluated the PlaCor PRT®, a novel platelet reactivity test based on shear-induced platelet aggregation, in patients with stable coronary artery disease (CAD) treated with single (SAPT) and dual antiplatelet therapy (DAPT). We examined 100 patients with multiple risk factors for CAD and/or documented stable CAD: 38 treated with SAPT, aspirin 100 mg qd, 62 treated with DAPT, aspirin 100 mg + clopidogrel 75 mg qd, compared with age- and sex-matched healthy volunteers without antiplatelet therapy (HV, n = 35). Measures of shear-induced platelet aggregation were performed with the PlaCor PRT®. In 25 patients in SAPT, the PlaCor test was also performed before and after a 12-hour-loading dose of clopidogrel 600 mg. The mean ± SD PRT time (seconds) in HV was 78 ± 13 and was significantly lower compared with SAPT (118 ± 16, p = 0.030) and to DAPT patients (242 ± 11, p < 0.0001). A statistically significant difference was also reported between SAPT and DAPT patients (p < 0.0001). After a loading dose of clopidogrel, the PRT time of SAPT patients increased significantly from 112 ± 20 to 254 ± 17, p < 0.0001. 2.7 and 26% of patients were considered as "poor responders" to single and dual antiplatelet therapy, respectively. This study shows that in patients with multiple risk factors for CAD and/or documented stable CAD, SAPT and DAPT play an important role in reducing platelet aggregation mediated by shear forces as evaluated with the novel PlaCor PRT®. Further studies will be required to confirm and assess the extent of these findings in patients with acute coronary syndromes.
authors: Cardio-Thoracic-Vascular Department, San Raffaele Institute , Milan , Italy.
authors: Cosmo
authors: C
authors: Godino
authors: Anna Giulia
authors: AG
authors: Pavon
authors: Antonio
authors: A
authors: Mangieri
authors: Giacomo Maria
authors: GM
authors: Viani
authors: Stefano
authors: S
authors: Galaverna
authors: Marco
authors: M
authors: Spartera
authors: Alaide
authors: A
authors: Chieffo
authors: Alberto
authors: A
authors: Cappelletti
authors: Alberto
authors: A
authors: Margonato
authors: Antonio
authors: A
authors: Colombo
mesh_terms: D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects*; D001800:Blood Specimen Collection / Q000379:methods*; D000077144:Clopidogrel; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D010979:Platelet Function Tests / Q000295:instrumentation / Q000379:methods*; D012307:Risk Factors; D033081:Shear Strength; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Aggregation; aspirin; clopidogrel; platelets; shear stress