title: [Intra-individual variability of the platelet anti-aggregation effect of aspirin in coronary patients].
abstract: Several studies have reported a biochemical resistance to aspirin in 5 to 10% of coronary patients. However, the stability of the platelet anti-aggregation effect with aspirin over time remains poorly understood.
  
  
  OBJECTIVE
  To study the intra-individual variability at 6 months of the anti-platelet action of aspirin in coronary patients.
  
  
  METHODS
  Prospective study including 40 consecutive patients with acute coronary syndrome and taking regular aspirin (250 mg a day). The biochemical impact of aspirin was determined by measuring the time to occlusion (TO) on a collagen/epinephrine cartridge with PFA-100. The determination of the TO was performed 2 months (TO1) and then 8 months (TO2) after starting aspirin. In our population, a resistance to aspirin was defined as a TO < or =125 sec.
  
  
  RESULTS
  The median value for TO was generally stable over the two periods, at 158 sec for TO1 and 179 sec for TO2 (p = 0.29). Among the 9 initially resistant patients (22.5%), 4 became sensitive to aspirin without changing the dosage, while only one of the 31 initially sensitive patients became biochemically resistant.
  
  
  CONCLUSIONS
  the existence of a medium term intra-individual variability in the antiplatelet response to aspirin in coronary patients underlines the importance of biochemical surveillance in these high vascular risk patients.
authors.affiliation: Service de cardiologie, CHU Fattouma Bourguiba, Tunisie. faouzi.addad@rns.tn
authors.forename: F
authors.initials: F
authors.lastname: Addad
authors.forename: M
authors.initials: M
authors.lastname: Hassine
authors.forename: M
authors.initials: M
authors.lastname: Ben Farhat
authors.forename: F
authors.initials: F
authors.lastname: Abderrazak
authors.forename: T
authors.initials: T
authors.lastname: Chakroun
authors.forename: H
authors.initials: H
authors.lastname: Gamra
authors.forename: S
authors.initials: S
authors.lastname: Hamdi
authors.forename: F
authors.initials: F
authors.lastname: Betbout
authors.forename: M
authors.initials: M
authors.lastname: Samama
authors.forename: I
authors.initials: I
authors.lastname: Elalamy
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D001241:Aspirin / Q000627:therapeutic use*; D003327:Coronary Disease / Q000188:drug therapy*; D004351:Drug Resistance; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D015203:Reproducibility of Results
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin