title: The effect of acetylsalicylic acid resistance on prognosis of patients who have developed acute coronary syndrome during acetylsalicylic acid therapy.
abstract: OBJECTIVE
  The relationships between clinical events and acetylsalicylic acid resistance (AR), as well as its frequency, have been established in stable patients with coronary artery disease (CAD). Although acute coronary syndrome (ACS) patients taking acetylsalicylic acid have been accepted as a high-risk population, the role of AR has not been investigated in these patient groups. Thus, in the present study, the impact of AR was investigated in patients with ACS who were taking acetylsalicylic acid.
  
  
  METHODS
  Between January 2001 and February 2003, 140 ACS patients were included in the present prospective study. All patients had ACS while taking acetylsalicylic acid. Coronary angiographic scores for severity and extent of CAD were determined for all patients. The effect of acetylsalicylic acid on platelet function was assessed by the platelet function analyzer PFA-100 (Dade Behring, USA). The primary end point was the composite of death, myocardial infarction, cerebrovascular accident and revascularization. The mean follow-up period was 20 months.
  
  
  RESULTS
  Patients with AR were older than patients without AR (63.8+/-10.8 years versus 58.3+/-11.2 years; P=0.005). Moreover, myocardial damage was higher in patients with AR according to cardiac troponin T values (1.11+/-1.3 mug/L versus 0.41+/-0.5 mug/L; P=0.01). The composite end point of death, myocardial infarction, cerebrovascular accident or revascularization was present in 16 of 45 patients (35%) with AR and in 13 of 79 patients (16%) without AR (hazard ratio 2.46, 95% CI 1.18 to 5.13; P=0.016). After adjustment for age, platelet count, cardiac troponin T value and CAD severity score, AR remained an independent predictor for long-term adverse events (hazard ratio 3.03, 95% CI 1.06 to 8.62; P=0.038).
  
  
  CONCLUSIONS
  The clinical event rate was found to be higher in ACS patients with AR than in those without AR. Thus, it may be concluded that there is a strong correlation between a worse prognosis and AR in these patients.
authors.affiliation: Siyami Ersek Thorax and Cardiovascular Surgery Center, Department of Cardiology, Istanbul, Turkey. ghobikoglu@hotmail.com
authors.forename: Gultekin F
authors.initials: GF
authors.lastname: Hobikoglu
authors.forename: Tugrul
authors.initials: T
authors.lastname: Norgaz
authors.forename: Huseyin
authors.initials: H
authors.lastname: Aksu
authors.forename: Orhan
authors.initials: O
authors.lastname: Ozer
authors.forename: Mehmet
authors.initials: M
authors.lastname: Erturk
authors.forename: Evren
authors.initials: E
authors.lastname: Destegul
authors.forename: Umit
authors.initials: U
authors.lastname: Akyuz
authors.forename: Sennur
authors.initials: S
authors.lastname: Unal Dai
authors.forename: Ahmet
authors.initials: A
authors.lastname: Narin
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001241:Aspirin / Q000494:pharmacology* / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D018849:Controlled Clinical Trials as Topic; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy*; D004351:Drug Resistance / Q000187:drug effects*; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D010976:Platelet Count; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012107:Research Design; D012720:Severity of Illness Index; D013577:Syndrome; D013997:Time Factors; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood / Q000187:drug effects
chemical_list: D015415:Biomarkers; D010975:Platelet Aggregation Inhibitors; D020107:Troponin T; D001241:Aspirin