title: Intrinsic platelet reactivity and thrombus burden in patients with ST-elevation myocardial infarction.
abstract: BACKGROUND
  In patients with ST elevation myocardial infarction (STEMI) increased platelet reactivity has been described to affect the primary percutanuous coronary intervention (PPCI) outcome. We aimed to evaluate the predictive accuracy of intrinsic platelet reactivity for intracoronary thrombus burden in P2Y12 inhibitor- naïve STEMI patients.
  
  
  METHODS
  In a prospective, observational, cohort study we enrolled 94 consecutive STEMI patients undergoing PPCI, subjected to platelet reactivity assessment prior to any P2Y12 blockade, with visible angiographic thrombus in the infarct related artery (stratified as Grade A, B and C). Platelet-function testing was performed with the VerifyNow point-of-care P2Y12 assay immediately prior to intervention.
  
  
  RESULTS
  Intrinsic platelet reactivity was higher with greater thrombus burden: Grade A 158.8±51.1 PRU, Grade B 217.4±62.1 PRU and Grade C 243.4±58.6 PRU, p=0.009 and Spearman r=0.32 (0.12-0.49 95% CI), p=0.002. ROC analysis revealed an AUC=0.7 (Standard error 0.07, p=0.03). An intrinsic platelet reactivity value of >220 PRU had 65% sensitivity (53-76 95%CI), 76% specificity (55-91 95%CI), 88% positive predictive value (76-96 95%CI) and 44% negative predictive value (29-60 95%CI) for detection of high thrombus burden. In multivariate analysis intrinsic platelet reactivity >220 PRU emerged as an independent predictor of high thrombus burden (RR=1.5, 1.15-2.07 95% CI, p=0.004).
  
  
  CONCLUSIONS
  In patients admitted with STEMI the intrinsic platelet reactivity -as assessed by a point-of-care assay- is positively associated with the degree of intracoronary thrombus, while having a moderate accuracy in predicting high thrombus burden.
authors.affiliation: Department of Cardiology, Patras University Hospital, Rion, Patras, Greece. dalex@med.upatras.gr
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Alexopoulos
authors.forename: Ioanna
authors.initials: I
authors.lastname: Xanthopoulou
authors.forename: Grigorios
authors.initials: G
authors.lastname: Tsigkas
authors.forename: Anastasia
authors.initials: A
authors.lastname: Damelou
authors.forename: Konstantinos C
authors.initials: KC
authors.lastname: Theodoropoulos
authors.forename: George
authors.initials: G
authors.lastname: Makris
authors.forename: Vassilios
authors.initials: V
authors.lastname: Gizas
authors.forename: George
authors.initials: G
authors.lastname: Kassimis
authors.forename: Periklis
authors.initials: P
authors.lastname: Davlouros
authors.forename: George
authors.initials: G
authors.lastname: Hahalis
mesh_terms: D001792:Blood Platelets / Q000473:pathology*; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000473:pathology / Q000601:surgery; D062645:Percutaneous Coronary Intervention; D010979:Platelet Function Tests; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013927:Thrombosis / Q000097:blood* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome