title: Randomized assessment of ticagrelor versus prasugrel antiplatelet effects in patients with ST-segment-elevation myocardial infarction.
abstract: BACKGROUND
  Ticagrelor and prasugrel provide stronger platelet inhibition compared with clopidogrel. Direct pharmacodynamic comparison between them has not yet been reported in ST-segment-elevation myocardial infarction patients.
  
  
  RESULTS
  In a prospective, single-center, single-blind study, 55 out of 117 (47%) screened consecutive ST-segment-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention were randomized to either ticagrelor 180 mg loading followed by 90 mg bid, or prasugrel 60 mg loading followed by 10 mg od for 5 days. Platelet reactivity (PR) was assessed with the VerifyNow P2Y12 function assay and the Multiplate Analyzer at 0, 1, 2, 6, 24 hours, and 5 days postrandomization. The primary end point, PR with VerifyNow at hour 1, did not differ significantly between patients randomized to ticagrelor versus prasugrel (257.3 P2Y12 reaction unit [PRU], 95% CI 230.8-283.8 versus 231.3 PRU, 95% CI 205.3-257.4; P=0.2). PR did not differ at 2, 6, and 24 hours, although at day 5 it was lower with ticagrelor than prasugrel (25.6 PRU, 95% CI 12.3-38.9 versus 50.3 PRU, 95% CI 36.4-64.1; P=0.01). At hour 2, high on-treatment PR rates (cutoff 208 PRU) were 46.2% and 34.6% for ticagrelor and prasugrel, respectively, decreased significantly thereafter, whereas did not differ significantly between the 2 agents at all the time points of the study.
  
  
  CONCLUSIONS
  In patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention, both ticagrelor and prasugrel exhibit an initial delay in the onset of their antiplatelet action. Ticagrelor did not appear superior to prasugrel in reducing PR during the first 24 hours of ST-segment-elevation myocardial infarction.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. Unique identifier: NCT01463163.
authors.affiliation: Department of Cardiology, Patras University Hospital, Rion, 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: Vassilios
authors.initials: V
authors.lastname: Gkizas
authors.forename: George
authors.initials: G
authors.lastname: Kassimis
authors.forename: Konstantinos C
authors.initials: KC
authors.lastname: Theodoropoulos
authors.forename: George
authors.initials: G
authors.lastname: Makris
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Koutsogiannis
authors.forename: Anastasia
authors.initials: A
authors.lastname: Damelou
authors.forename: Grigorios
authors.initials: G
authors.lastname: Tsigkas
authors.forename: Periklis
authors.initials: P
authors.lastname: Davlouros
authors.forename: George
authors.initials: G
authors.lastname: Hahalis
mesh_terms: D000241:Adenosine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000368:Aged; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D004334:Drug Administration Schedule; D005260:Female; D006115:Greece; D006801:Humans; D016018:Least-Squares Analysis; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000628:therapy*; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects; D010879:Piperazines / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010979:Platelet Function Tests; D000068799:Prasugrel Hydrochloride; D011446:Prospective Studies; D058921:Purinergic P2Y Receptor Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D058925:Receptors, Purinergic P2Y12 / Q000187:drug effects / Q000378:metabolism; D016037:Single-Blind Method; D013876:Thiophenes / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000077486:Ticagrelor; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: C548576:P2RY12 protein, human; D010879:Piperazines; D010975:Platelet Aggregation Inhibitors; D058921:Purinergic P2Y Receptor Antagonists; D058925:Receptors, Purinergic P2Y12; D013876:Thiophenes; D000068799:Prasugrel Hydrochloride; D000077486:Ticagrelor; D000241:Adenosine