title: Factors Affecting Platelet Reactivity 2 Hours After P2Y₁₂ Receptor Antagonist Loading in Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction - Impact of Pain-to-Loading Time.
abstract: BACKGROUND
  Delay in the onset of antiplatelet action occurs in patients with ST-elevation myocardial infarction (STEMI) and is likely due to disturbed absorption. We hypothesized that patients presenting relatively late after the onset of symptoms would have faster antiplatelet action.
  
  
  RESULTS
  We analyzed patient-level data from 5 studies of 207 P2Y12 receptor antagonist-naïve patients with STEMI undergoing primary percutaneous coronary intervention (PCI). All patients had available platelet reactivity (PR) assessment with the VerifyNow assay (in P2Y12 reaction units; PRU) prior to and 2 h after loading. High PR (HPR) was defined as ≥ 208 PRU. Pain-to-antiplatelet loading time independently predicted PR at 2 h after loading: every 1-h increase in pain-to-antiplatelet loading time produced a 7% decrease in PR (P=0.001). Pretreatment PR, body mass index, morphine and novel P2Y12 receptor antagonist also affected PR 2 h after loading. Novel P2Y12 receptor antagonist use and per hour increase in pain-to-antiplatelet loading time were independently associated with lower probability for HPR with an OR (95% CI) of 0.145 (0.095-0.220) and 0.776 (0.689-0.873), P<0.001 for both (C-statistic, 0.752; 95% CI: 0.685-0.819).
  
  
  CONCLUSIONS
  In STEMI patients undergoing primary PCI, pain-to-antiplatelet loading interval is a newly described factor affecting PR shortly after P2Y12 receptor antagonist loading, according to patient-level data pooled analysis.
authors.affiliation: Department of Cardiology, Patras University Hospital.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Xanthopoulou
authors.forename: Periklis
authors.initials: P
authors.lastname: Davlouros
authors.forename: Grigorios
authors.initials: G
authors.lastname: Tsigkas
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Koutsogiannis
authors.forename: Sotirios
authors.initials: S
authors.lastname: Patsilinakos
authors.forename: Spyridon
authors.initials: S
authors.lastname: Deftereos
authors.forename: George
authors.initials: G
authors.lastname: Hahalis
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Alexopoulos
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000628:therapy*; D010146:Pain / Q000097:blood; D062645:Percutaneous Coronary Intervention; D015539:Platelet Activation / Q000187:drug effects*; D058921:Purinergic P2Y Receptor Antagonists / Q000008:administration & dosage*; D058925:Receptors, Purinergic P2Y12 / Q000097:blood*; D013997:Time Factors
chemical_list: C548576:P2RY12 protein, human; D058921:Purinergic P2Y Receptor Antagonists; D058925:Receptors, Purinergic P2Y12