Is chronic nitrate therapy associated with a different clinical presentation of acute coronary syndrome?
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.
Timóteo
Ana Teresa
AT
Serviço de Cardiologia, Hospital de Santa Marta, Lisboa, Portugal. ana_timoteo@yahoo.com
Mamede
Andreia
A
de Lurdes Ferreira
Maria
M
Serra
José
J
Oliveira
José Alberto
JA
Ferreira
Rui Cruz
RC
Quininha
Jorge
J
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
D009566:Nitrates