title: Platelet reactivity evaluated with the VASP assay following ticagrelor loading dose in acute coronary syndrome patients undergoing percutaneous coronary intervention.
abstract: BACKGROUND
  The level of platelet reactivity (PR) inhibition obtained after P2Y12-ADP receptor antagonist loading dose (LD) is associated with the ischemic and bleeding risk following percutaneous coronary intervention (PCI) in acute coronary syndromes (ACS).
  
  
  OBJECTIVE
  We aimed to evaluate the level of PR inhibition achieved by a 180 mg LD of ticagrelor and the rate of high on-treatment platelet reactivity (HTPR) in ACS patients undergoing PCI.
  
  
  METHODS
  We performed a multicentre prospective observational study enrolling ACS patients undergoing PCI. Patients were included if they were admitted for ST-elevation myocardial infarction or non ST-elevation ACS. To assess PR, a VASP index was measured at least 6 and within 24 hours following a 180 mg LD of ticagrelor. HTPR was defined as a VASP index ≥50%.
  
  
  RESULTS
  One hundred and fifteen patients were included: 31.3% of STEMI, 49.6% of NSTEMI and 19.1% of unstable angina. Following ticagrelor LD the mean VASP index was 17±14%. However the response to ticagrelor was not uniform with a small inter-individual variability: inter quartile range: 7.6-22.8% and a rate of HTPR of 3.5%. A high number of patients, 65.6%, had a VASP index <16%. None of the baseline characteristics of the study population was associated with PR. In addition, PR was similar in STEMI, NSTEMI and unstable angina (p=0.9).
  
  
  CONCLUSIONS
  In ACS patients the level of PR inhibition achieved by a 180 mg loading dose of ticagrelor is not uniform and the rate of HTPR is 3.5%. A high proportion of patients exhibited a VASP index <16%.
authors.affiliation: Département de cardiologie, Hôpital universitaire nord, Aix-Marseille Univ., Marseille, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Laine
authors.forename: Richard
authors.initials: R
authors.lastname: Toesca
authors.forename: Julie
authors.initials: J
authors.lastname: Berbis
authors.forename: Corinne
authors.initials: C
authors.lastname: Frere
authors.forename: Pierre
authors.initials: P
authors.lastname: Barnay
authors.forename: Michel
authors.initials: M
authors.lastname: Pansieri
authors.forename: Jean-Pascal
authors.initials: JP
authors.lastname: Peyre
authors.forename: Pierre
authors.initials: P
authors.lastname: Michelet
authors.forename: Jacques
authors.initials: J
authors.lastname: Bessereau
authors.forename: Elise
authors.initials: E
authors.lastname: Camilleri
authors.forename: Olfa
authors.initials: O
authors.lastname: Helaf
authors.forename: Marjorie
authors.initials: M
authors.lastname: Camaleonte
authors.forename: Franck
authors.initials: F
authors.lastname: Paganelli
authors.forename: Françoise
authors.initials: F
authors.lastname: Dignat-George
authors.forename: Laurent
authors.initials: L
authors.lastname: Bonello
mesh_terms: D054058:Acute Coronary Syndrome / Q000601:surgery*; D000241:Adenosine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000368:Aged; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention / Q000379:methods; D015539:Platelet Activation / Q000187:drug effects*; D011446:Prospective Studies; D058919:Purinergic P2 Receptor Antagonists / Q000627:therapeutic use*; D000077486:Ticagrelor
chemical_list: D058919:Purinergic P2 Receptor Antagonists; D000077486:Ticagrelor; D000241:Adenosine
keywords: ACS; Acute coronary syndromes; HTPR; LD; LTPR; NSTEMI; On-treatment platelet reactivity; P2Y12-ADP receptor antagonist; PCI; PR; ST segment elevation myocardial infarction; STEMI; Ticagrelor; VASP; VASP index; Vasodilator-stimulated phosphoprotein; acute coronary syndrome; high on-treatment platelet reactivity; loading dose; low on-treatment platelet reactivity; non ST segment elevation myocardial infarction; percutaneous coronary intervention; platelet reactivity