title: The role of aspirin resistance on outcome in patients with acute coronary syndrome and the effect of clopidogrel therapy in the prevention of major cardiovascular events.
abstract: BACKGROUND
  Aspirin resistance may increase up to more then threefold the risk of major cardiovascular events (MACE) in patients with stable coronary artery disease.
  
  
  OBJECTIVE
  The aim of our study was to determine; the prevalence of aspirin resistance in patients with acute coronary syndromes, the role of aspirin resistance on outcome in the follow-up and the effect of clopidogrel therapy in the prevention of MACE in aspirin resistant subjects.
  
  
  METHODS
  We detected the prevelance of aspirin resistance in 105 patients with acute coronary syndrome. Platelet functions were analyzed in Platelet Function Analyzer (PFA)-100 (Dade Behring, Germany) with collagen and/or epinephrine (Col/Epi) and collagen and/or ADP (Col/ADP) cartridges. Primary end points of the study were myocardial infarction, unstable angina, cardiac death.
  
  
  RESULTS
  19% (n = 20) of patients were aspirin resistant by PFA-100. In the follow-up, MACE occured in 9 patients (45%) with aspirin resistance and in 10 patients (11.7%) with aspirin sensitive platelet aggregation (p = 0.001). Multivariate analysis showed that aspirin resistance was an independant predictor of MACE. The prevalence of MACE in patients who were on clopidogrel treatment for 12 months were lower compared to those who were on a clopidogrel treatment for the first six months (p = 0.040).
  
  
  CONCLUSIONS
  We determined that the MACE risk in patients with acute coronary syndromes having detected aspirin resistance, was higher at statistically significant levels compared to patients having aspirin sensitive platelet aggregation. Our results showed that aspirin resistance, was an independant predictor of MACE in patients with acute coronary syndrome.
authors.affiliation: Istanbul Faculty of Medicine, Department of Cardiology, Istanbul University, Hasan Halife Mahallesi Oksuzler Sokak No: 9 K:2 D: 4 Fatih, Istanbul, Turkey 34080. bpamukcu@gmail.com
authors.forename: Burak
authors.initials: B
authors.lastname: Pamukcu
authors.forename: Huseyin
authors.initials: H
authors.lastname: Oflaz
authors.forename: Aytac
authors.initials: A
authors.lastname: Oncul
authors.forename: Berrin
authors.initials: B
authors.lastname: Umman
authors.forename: Fehmi
authors.initials: F
authors.lastname: Mercanoglu
authors.forename: Mustafa
authors.initials: M
authors.lastname: Ozcan
authors.forename: Mehmet
authors.initials: M
authors.lastname: Meric
authors.forename: Yilmaz
authors.initials: Y
authors.lastname: Nisanci
mesh_terms: D000789:Angina, Unstable / Q000209:etiology / Q000517:prevention & control*; D001241:Aspirin / Q000494:pharmacology*; D000077144:Clopidogrel; D003324:Coronary Artery Disease / Q000150:complications; D004351:Drug Resistance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology / Q000517:prevention & control*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D010979:Platelet Function Tests; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors; D011446:Prospective Studies; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin