title: The effect of correcting VerifyNow P2Y12 assay results for hematocrit in patients undergoing percutaneous coronary interventions.
abstract: Essentials Platelet reactivity is correlated with thrombotic risk after percutaneous coronary intervention (PCI). Hematocrit (HCT) is associated with platelet reactivity as measured with the VerifyNow P2Y12assay. We tested a formula proposed to correct VerifyNow measurements for HCT in 978 PCI patients. Correcting platelet reactivity for HCT did not improve the prediction of thrombotic events after PCI.
  
  
  
  Background High on-treatment platelet reactivity is predictive for the occurrence of atherothrombotic events following percutaneous coronary interventions (PCIs). A low hematocrit (HCT) value is associated with higher platelet reactivity values, expressed in P2Y12reaction units (PRU), as measured with the VerifyNow P2Y12assay. However, it is suggested that this is only an in vitro phenomenon. Objective To determine whether adjusting PRU for HCT improves the predictive value for thrombotic events following PCI. Material and methods The VerifyNow P2Y12assay was performed in clopidogrel-treated patients undergoing non-urgent PCI included in a prospective cohort study. PRU values were corrected for HCT with a formula proposed in recent literature. Receiver operating characteristic (ROC) curves were made to determine the optimal cut-off values to predict the occurrence of the primary endpoint, a composite of all-cause death and non-fatal myocardial infarction, stent thrombosis and ischemic stroke, during 1 year of follow-up. The chi-squared test was performed to determine whether correcting PRU for HCT improved the prediction of the primary endpoint. Results A total of 978 patients were analyzed. A negative correlation between PRU and HCT was observed (R2= 0.104). The optimal cut-off value for the corrected PRU was 215. ROC analyses showed that prediction of the primary endpoint did not differ for the corrected PRU (area under the curve, 0.61; sensitivity, 0.57; specificity, 0.64) and the uncorrected PRU (area under the curve, 0.61; sensitivity, 0.69; specificity, 0.53). Conclusion Correcting PRU for HCT does not improve the prediction of thrombotic events following PCI.
authors.affiliation: Department of Cardiology, St Antonius Hospital, Nieuwegein, the Netherlands.|St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: P W A
authors.initials: PW
authors.lastname: Janssen
authors.affiliation: Department of Cardiology, St Antonius Hospital, Nieuwegein, the Netherlands.|St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: T O
authors.initials: TO
authors.lastname: Bergmeijer
authors.affiliation: Department of Cardiology, St Antonius Hospital, Nieuwegein, the Netherlands.|St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: T C
authors.initials: TC
authors.lastname: Godschalk
authors.affiliation: Department of Cardiology, St Antonius Hospital, Nieuwegein, the Netherlands.|St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: T T D
authors.initials: TT
authors.lastname: Le
authors.affiliation: Department of Cardiology, St Antonius Hospital, Nieuwegein, the Netherlands.|St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: N J
authors.initials: NJ
authors.lastname: Breet
authors.affiliation: Department of Cardiology, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: J C
authors.initials: JC
authors.lastname: Kelder
authors.affiliation: St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, the Netherlands.|Department of Clinical Chemistry, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: C M
authors.initials: CM
authors.lastname: Hackeng
authors.affiliation: Department of Cardiology, St Antonius Hospital, Nieuwegein, the Netherlands.|St Antonius Center for Platelet Function Research, St Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Ten Berg
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001792:Blood Platelets / Q000187:drug effects; D000077144:Clopidogrel; D005260:Female; D005500:Follow-Up Studies; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D010979:Platelet Function Tests; D011446:Prospective Studies; D012372:ROC Curve; D058925:Receptors, Purinergic P2Y12 / Q000032:analysis* / Q000378:metabolism; D012306:Risk; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000097:blood / Q000188:drug therapy; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D058925:Receptors, Purinergic P2Y12; D000077144:Clopidogrel; D013988:Ticlopidine
keywords: clopidogrel; hematocrit; percutaneous coronary intervention; platelet aggregation; platelet function tests