title: Is chronic nitrate therapy associated with a different clinical presentation of acute coronary syndrome?
abstract: BACKGROUND
  Nitrate therapy can induce ischemic preconditioning with a consequent increase in tolerance to ischemia. In the context of acute coronary syndromes (ACS), nitrates may result in a different presentation. with greater protection.
  
  
  OBJECTIVE
  To investigate in a population of patients with ACS whether previous chronic use of nitrates results in a different presentation of ACS.
  
  
  METHODS
  We studied 287 patients (65 +/- 13 years, 66% male) admitted to our department in the first six months of 2005 with ACS (with and without ST-segment elevation). Of these, 8% were under nitrate therapy at the time of admission. In this group, 27% presented ACS without ST-segment elevation, while in the group without nitrates this value was 58% (p = 0.005). By univariate analysis, the use of nitrates was a predictor of the preferential occurrence of non-ST-segment elevation ACS (OR 0.27, 95% CI 0.10-0.71). After correction for the potential influence of variables (age, gender, previous revascularization and smoking) by multivariate logistic regression, nitrate therapy remained a borderline predictor of clinical presentation as non-ST-segment elevation ACS (OR 0.37, 95% CI 0.13-1.04, p = 0.059).
  
  
  CONCLUSIONS
  Previous use of nitrates was associated with a tendency to present as non-ST-segment elevation ACS. This finding may be explained by the hypothesis that nitrates induce pharmacological preconditioning, reducing the transmural extent of myocardial infarction.
authors.affiliation: Serviço de Cardiologia, Hospital de Santa Marta, Lisboa, Portugal. ana_timoteo@yahoo.com
authors.forename: Ana Teresa
authors.initials: AT
authors.lastname: Timóteo
authors.forename: Andreia
authors.initials: A
authors.lastname: Mamede
authors.forename: Maria
authors.initials: M
authors.lastname: de Lurdes Ferreira
authors.forename: José
authors.initials: J
authors.lastname: Serra
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Oliveira
authors.forename: Rui Cruz
authors.initials: RC
authors.lastname: Ferreira
authors.forename: Jorge
authors.initials: J
authors.lastname: Quininha
mesh_terms: D000208:Acute Disease; D000368:Aged; D000789:Angina, Unstable / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D009566:Nitrates / Q000627:therapeutic use*; D011446:Prospective Studies; D013577:Syndrome
chemical_list: D009566:Nitrates