title: [Frequency and characteristics of aspirin resistance in Chilean cardiovascular patients].
abstract: BACKGROUND
  Studies performed in Anglo-Saxon countries show that 5% of patients are resistant to the antiplatelet effects of aspirin.
  
  
  OBJECTIVE
  To assess the prevalence of aspirin resistance in a sample of Chilean cardiovascular patients and its association with clinical and laboratory characteristics.
  
  
  METHODS
  Ninety nine patients (30 women, 63+/-10 years) treated for stable cardiovascular diseases with aspirin 100-325 mg/day were studied. Clinical and basic coagulation variables were assessed. Platelet aggregation was studied with platelet rich plasma using three different agonists in an optical aggregometer. Aspirin resistance was defined as an aggregation 20% with arachidonic acid and an aggregation 70% with ADP or collagen.
  
  
  RESULTS
  Eleven patients (11.11%, 95% CI= 4.95-17.27%) complied with both criteria and were classified as aspirin resistant. Current smoking was more common in aspirin resistant patients (63.6 vs 29.6%, p=0.039).
  
  
  CONCLUSIONS
  Aspirin resistance was found in a significant proportion of cardiovascular patients and was more common among current smokers.
authors.affiliation: Sección de Hematología, Hospital Clínico de la Universidad de Chile, Av. Santos Dumont 999, Independencia, Santiago, Chile. gdussailant@redclinicauchile.cl
authors.forename: Gastón
authors.initials: G
authors.lastname: Dussaillant N
authors.forename: Mario
authors.initials: M
authors.lastname: Zapata M
authors.forename: Patricia
authors.initials: P
authors.lastname: Fardella B
authors.forename: Guillermo
authors.initials: G
authors.lastname: Conte L
authors.forename: Marianela
authors.initials: M
authors.lastname: Cuneo V
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D002318:Cardiovascular Diseases / Q000188:drug therapy*; D002677:Chile; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D012907:Smoking / Q000009:adverse effects
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin