Objective The aim of the study was to assess the differences in clinical and morphologic characteristics of culprit lesions among patients with unstable angina (UA) and non-ST-elevation myocardial infarction (NSTEMI).

Methods The authors included 174 consecutive patients who have been admitted due to UA or NSTEMI. All patients underwent coronary angiography during hospitalisation and angiographic characteristics were determined.

Results The mean age of study patients was 57±9 years, and the majority were men. The frequency of single, two and three vessel disease was 35.6%, 28.7% and 28.1%, respectively. There was no significant difference between UA and NSTEMI patients in terms of the extent of coronary artery involvement and culprit lesion morphologic features (p value: 0.99 and 0.67, respectively). The only significant difference was the incidence of definite and possible thrombus in culprit lesion (40.7% vs 16.5%, p value<0.001). The authors also did not find any association between Braunwald clinical/severity classification and lesion morphology in the studied population. In multivariate analysis there was a significant association between Braunwald class II–III and increased risk of NSTEMI (OR (95% CI): 13.43 (1.12 to 160.63), p=0.04, OR (95% CI): 14.08 (1.21 to 163.11), p=0.03, for Braunwald severity class II and III, respectively).

Conclusion Clinical characteristics of patients with acute coronary syndrome including enzyme rising cannot predict the extent of coronary artery involvement and the morphology of culprit lesions. The only exception was the higher incidence of intracoronary thrombus in patients with NSTEMI as compared with UA.