title: Changes in platelet function independent of pharmacotherapy following coronary intervention in non-ST-elevation myocardial infarction patients.
abstract: BACKGROUND
  High on treatment platelet reactivity (HTPR) is common in patients receiving clopidogrel following an acute coronary syndrome (ACS); it's also associated with increased morbidity and mortality. More potent and predictable antiplatelet drugs have addressed this issue at the expense of increased bleeding. Identification of HTPR and the targeted use of more potent antiplatelet drugs has, so far, broadly failed. We investigate this approach in terms of the timing of platelet function testing and how this can impact on the ability of these bedside tests to predict HTPR around the time of coronary intervention.
  
  
  METHODS
  High risk ACS patients treated with 5 days of clopidogrel had platelet function assessed using the multiple electrode aggregometry system (MEA) pre, post and 24 h following percutaneous coronary intervention (PCI). Simultaneous detailed analysis of platelet status was undertaken with quantification of platelet bound and soluble p-selectin and mass spectrometry quantification of the eicosanoid 12-HETE.
  
  
  RESULTS
  As assessed by MEA 40.5% of patients had HTPR pre-PCI; mean aggregation units (AU) in response to ADP were 499.1 ± 46.3 pre-PCI, 407.6 ± 37.7 post-PCI and 269.1 ± 24.6 AU 24 h post-PCI (pre to post PCI p > 0.05, pre to 24 h post-PCI p = 0.0002). This highly significant drop in platelet reactivity was contrasted with on-going expression of platelet bound p-selectin, increased soluble p-selectin and rising 12-HETE concentrations.
  
  
  CONCLUSIONS
  This study outlines significant changes in ex-vivo platelet aggregation that occur within 24 h of PCI in high risk NSTEMI patients using bedside PFT. Whilst there were no changes in antiplatelet therapy during the study period its clear that timing is crucial when assessing high on treatment residual platelet activity.
authors.affiliation: Cardiff University School of Medicine, Institute of Molecular and Experimental Medicine, UK; Cardiothoracic Directorate, University Hospital of Wales, UK. Electronic address: phillip@fischerfreeman.com.
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Freeman
authors.affiliation: Cardiff University School of Medicine, Institute of Molecular and Experimental Medicine, UK.
authors.forename: Konstantinos E
authors.initials: KE
authors.lastname: Moschonas
authors.affiliation: Cardiff University School of Medicine, Institute of Infection and Immunity, UK.
authors.forename: Christine
authors.initials: C
authors.lastname: Hinz
authors.affiliation: Cardiff University School of Medicine, Institute of Infection and Immunity, UK.
authors.forename: Valerie B
authors.initials: VB
authors.lastname: O'Donnell
authors.affiliation: Cardiothoracic Directorate, University Hospital of Wales, UK.
authors.forename: Tim D
authors.initials: TD
authors.lastname: Kinnaird
authors.affiliation: Cardiff University School of Medicine, Institute of Molecular and Experimental Medicine, UK.
authors.forename: Philip E
authors.initials: PE
authors.lastname: James
authors.affiliation: Cardiothoracic Directorate, University Hospital of Wales, UK.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Anderson
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000737:chemistry; D054058:Acute Coronary Syndrome / Q000097:blood* / Q000188:drug therapy*; D000244:Adenosine Diphosphate / Q000737:chemistry; D000368:Aged; D001792:Blood Platelets / Q000166:cytology*; D002853:Chromatography, Liquid; D000077144:Clopidogrel; D004566:Electrodes; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D049449:Luminescence; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009203:Myocardial Infarction / Q000628:therapy*; D019007:P-Selectin / Q000378:metabolism; D062645:Percutaneous Coronary Intervention; D010974:Platelet Aggregation; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry; D010979:Platelet Function Tests; D011446:Prospective Studies; D053719:Tandem Mass Spectrometry; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; C546937:SELP protein, human; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000244:Adenosine Diphosphate; D000077144:Clopidogrel; D013988:Ticlopidine
keywords: Acute coronary syndrome; Clopidogrel; Platelet function testing; Residual platelet reactivity