Occasionally, coronary arteries without significant stenosis are observed during invasive treatment of acute non-ST-elevation myocardial infarction (NSTEMI). The aim was to investigate predictive factors and prognosis in these patients.

The study involved 165 patients admitted for NSTEMI who underwent cardiac catheterization. The primary end-point was the observation of coronary arteries without significant stenosis, and the secondary end-point was death or myocardial infarction within a median of 2 years.

Overall, 21 patients (13%) had coronary arteries without significant lesions. The predictors were: female sex (odds ratio [OR] = 6.4; P=.0001), age <55 years (OR=3.2; P=.001), and the absence of diabetes (OR=2.8, P=.0001), previous antiplatelet treatment (OR=3.9, P=.0001).

The composite variable of female sex plus at least 2 additional predictive factors had a specificity of 89% and a sensitivity of 63% for coronary angiography showing no significant stenosis. The absence of coronary artery stenosis decreased the probability of death or myocardial infarction during followup (hazard ratio = 0.3, 95% confidence interval, 0.2-0.9; P=.03).

In NSTEMI, female sex, age <55 years and the absence of diabetes, previous antiplatelet treatment were all associated with coronary angiography showing no significant stenosis. The longterm prognosis in these patients was good.