title: The golden hour of prehospital reperfusion with triple antiplatelet therapy: a sub-analysis from the Ongoing Tirofiban in Myocardial Evaluation 2 (On-TIME 2) trial early initiation of triple antiplatelet therapy.
abstract: BACKGROUND
  It is known that the efficacy of thrombolytic therapy in ST-segment elevation myocardial infarction (STEMI) is highly time dependent with the best efficacy when given within the so-called golden hour. This analysis from the On-TIME 2 trial evaluated the efficacy of triple antiplatelet therapy on initial patency and ST-segment resolution (STR) in relation to time from symptom onset to first medical contact.
  
  
  METHODS
  The On-TIME 2 trial included 1,398 consecutive STEMI patients referred for primary percutaneous coronary intervention (PCI). Patients were randomized to dual (500 mg aspirin and 600 mg clopidogrel) or triple antiplatelet (500 mg aspirin, 600 mg clopidogrel, and tirofiban 25 μg/kg bolus and 0.15 μg/kg per minute maintenance infusion for 18 hours) pretreatment in the ambulance. Primary outcome of this sub-analysis was initial patency of the infarct-related vessel and STR before PCI according to time from symptom onset to first medical contact in quartiles. In addition, the incidence of aborted myocardial infarction, defined as the absence of a rise in creatinine kinase, was assessed.
  
  
  RESULTS
  Initial patency, STR before PCI, and the incidence of aborted myocardial infarction gradually increased with shorter time from symptom onset to first medical contact. Initial Thrombolysis in Myocardial Infarction flow was present in 21.2% in the total population and 26.2%, 21.5%, 18.1%, and 18.8% in the time quartiles, respectively (P for trend=.01). The incidence of complete STR pre-angiography was 16.6% in the total population and 23.4%, 18.2%, 14.7%, and 9.9% in the 4 quartiles, respectively (P for trend<.001). This was largely driven by the effect of triple antiplatelet therapy, which further improved initial patency and STR and led to a significantly higher incidence of aborted myocardial infarction (13.2% vs 8.7%, P=.011), especially in the patients with short duration of symptoms.
  
  
  CONCLUSIONS
  Antiplatelet pretreatment before primary PCI, including a glycoprotein IIb/IIIa blocker, seems to be most effective when given shortly after symptom onset. Further studies should be performed to test this hypothesis.
authors.affiliation: Department of Cardiology, Medisch Centrum Alkmaar, Alkmaar, The Netherlands.
authors.forename: Ton
authors.initials: T
authors.lastname: Heestermans
authors.forename: Arnoud W J
authors.initials: AW
authors.lastname: van 't Hof
authors.forename: Jurriën M
authors.initials: JM
authors.lastname: ten Berg
authors.forename: Jochem W
authors.initials: JW
authors.lastname: van Werkum
authors.forename: Eric
authors.initials: E
authors.lastname: Boersma
authors.forename: Arend
authors.initials: A
authors.lastname: Mosterd
authors.forename: Pieter R
authors.initials: PR
authors.lastname: Stella
authors.forename: Arthur B
authors.initials: AB
authors.lastname: van Zoelen
authors.forename: A T Marcel
authors.initials: AT
authors.lastname: Gosselink
authors.forename: Waclav
authors.initials: W
authors.lastname: Kochman
authors.forename: Thorsten
authors.initials: T
authors.lastname: Dill
authors.forename: Petra C
authors.initials: PC
authors.lastname: Koopmans
authors.forename: Gert
authors.initials: G
authors.lastname: van Houwelingen
authors.forename: Felix
authors.initials: F
authors.lastname: Zijlstra
authors.forename: Christian
authors.initials: C
authors.lastname: Hamm
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors*; D013997:Time Factors; D000077466:Tirofiban; D016896:Treatment Outcome; D014443:Tyrosine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D055815:Young Adult
chemical_list: D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D014443:Tyrosine; D000077466:Tirofiban