Point-of-care platelet function testing in patients undergoing PCI: between a rock and a hard place

Abstract

Point-of-care platelet function testing in patients undergoing PCI: between a rock and a hard place Since recent studies have linked an impaired response to antiplatelet therapy with a higher incidence of atherothrombotic events, the monitoring of the efficacy of antiplatelet therapy in the individual patient has attracted much attention. In the present report, we demonstrate that platelet function testing with several point-of-care assays results in ambiguous and conflicting results: some assays indicated that the patient's platelets were insufficiently inhibited by clopidogrel whereas other assays reported an adequate response. Therefore, platelet function assays should not be used solely to guide treatment decisions, and tailor-made antithrombotic treatment has to wait for the most predictive platelet function test to emerge for measuring the risk for thrombotic complications after stenting. Until then, daily clinical practice should not be guided by point-of-care platelet function testing. (Neth Heart J 2007;15:299-305).

P2Y12 Platelet Function Assay for Assessment of Bleeding Risk in Coronary Artery Bypass Grafting

“…However, in the same study, they reported that results from two other platelet aggregation tests, PFA‐100 and platelet works, were not predictive of perioperative bleeding and transfusions . Subsequent studies have also demonstrated substantial variability and even conflicting results from different point‐of‐care platelet function assays . This suggests that individual assays must be independently validated.…”

“…13 Subsequent studies have also demonstrated substantial variability and even conflicting results from different point-of-care platelet function assays. 17 This suggests that individual assays must be independently validated.…”

Pharmacokinetic, pharmacodynamic, and pharmacogenetic assays to monitor clopidogrel therapy

“…Usually, reference platelet count taken from the K3-EDTA anticoagulant blood without ADP and other count is taken from citrated anticoagulant sample with ADP agonist. 71 In normal patients, the platelets get aggregated in the presence of agonist and the resultant platelet count is considered to be zero.…”

“…72 When the platelet aggregates Minimum studies have been conducted to show the prediction of outcomes of cardiovascular diseases. 71,73,76 In the determination of the cut-off values for Plateletworks assay, it had shown 63% sensitivity and 58.5% specificity using ROC curve analysis. 74 Around 5%-40% of patients who are under clopidogrel therapy may show resistance to clopidogrel and the cause may be due to impaired drug absorption by the hepatic cells or impaired drug metabolic activity.…”

Cangrelor increases the magnitude of platelet inhibition and reduces interindividual variability in clopidogrel-pretreated subjects

“…9,10 However, platelet function was measured with impedance aggregometry, a method that has not been very well studied with respect to P2Y 12 inhibition. 11 Therefore, we aimed to study the effect of cangrelor on platelet aggregation in patients pretreated with aspirin and clopidogrel using the 'gold standard' light transmittance aggregometry (LTA).…”