Measurement of shear-activated platelet aggregate formation in non-anticoagulated blood: utility in detection of clopidogrel-aspirin-induced platelet dysfunction

• Published in: Clinical and applied thrombosis/hemostasis Vol. 18; no. 2; p. 140
• Main Authors: Johnson, Gerhard J, Sharda, Anish V, Rao, Gundu H R, Ereth, Mark H, Laxson, David D, Owen, Whyte G
• Format: Journal Article
• Language: English
• Published: United States 01-03-2012
• Subjects: Adult; Aged; Aged, 80 and over; Aspirin - administration & dosage; Aspirin - adverse effects; Aspirin - pharmacology; Aspirin - therapeutic use; Blood Platelet Disorders - blood; Blood Platelet Disorders - chemically induced; Blood Platelet Disorders - diagnosis; Blood Specimen Collection - methods; Cardiovascular Diseases - blood; Collagen - pharmacology; Cross-Sectional Studies; Drug Synergism; Drug Therapy, Combination; Equipment Design; Female; Humans; Male; Middle Aged; Platelet Activation; Platelet Aggregation - drug effects; Platelet Aggregation Inhibitors - adverse effects; Platelet Aggregation Inhibitors - pharmacology; Platelet Aggregation Inhibitors - therapeutic use; Platelet Function Tests - instrumentation; Reproducibility of Results; Risk Factors; Stress, Mechanical; Thrombophilia - blood; Thrombophilia - drug therapy; Ticlopidine - administration & dosage; Ticlopidine - adverse effects; Ticlopidine - analogs & derivatives; Ticlopidine - pharmacology; Ticlopidine - therapeutic use; Warfarin - adverse effects; Warfarin - pharmacology; Warfarin - therapeutic use
• ISSN: 1938-2723
• DOI: 10.1177/1076029611423387

We studied the ability of a new instrument, the PlaCor PRT that measures shear-induced platelet aggregation in fingerstick, non-anticoagulated blood without added agonists, to detect platelet dysfunction ex vivo. Platelet reactivity time (PRT) and whole blood aggregation (WBA) were measured in 160 healthy volunteers, before and after aspirin and in 170 participants with established vascular disease or risk factors thereof treated with aspirin ± clopidogrel. Pretreatment PRT and WBA were significantly correlated (collagen r = -.63; arachidonate r = -.65; P < .0001). Following aspirin, the mean PRT increased from 82 to 142 seconds (P < .0001), and in participants treated with clopidogrel-aspirin, the mean PRT (286 seconds, n = 65) was significantly longer than with aspirin alone (166 seconds, n = 105; P < .001). Only 13% of PRTs of participants treated with clopidogrel and aspirin were within the normal range. We conclude that the PlaCor PRT is a simple, rapid, point-of-care instrument that compares favorably with published descriptions of other platelet function instruments.