['Several studies have shown higher early mortality for ST-segment elevation acute coronary syndrome (STEACS), but late mortality remains consistently higher for non-ST-segment elevation acute coronary syndrome (NSTEACS). We hypothesized that ST-segment category at acute presentation is associated with the time course of coronary artery disease progression (CP) of nonculprit lesions in patients with acute coronary syndrome (ACS).', 'A total of 226 patients (182 men, age 65\xa0±\xa010\xa0years) with STEACS (n\xa0=\xa095) or NSTEACS (n\xa0=\xa0131) who underwent percutaneous coronary intervention (PCI) during initial hospitalization were studied. All patients underwent serial coronary angiograms (CAGs) performed immediately before PCI and at 7\xa0±\xa03\xa0months and 60\xa0±\xa010\xa0months after presentation. CP was defined as an increase in stenosis severity >15% of a nonculprit lesion between 2 serial CAGs.', 'The rate of CP between the first and second CAGs did not differ by ST-segment category at acute presentation. Compared to STEACS, NSTEACS had a higher rate of CP between the second and final CAGs (27.4 vs. 42.7%, P\xa0=\xa00.018). Multivariate analysis showed that the independent predictors of CP between the second and final CAGs were NSTEACS (odds ratio 2.709, P\xa0=\xa00.003), estimated glomerular filtration rate <60\xa0ml/min/1.73\xa0m'] Is sT-segment category at acute presentation associated with the time course of coronary artery disease progression in patients with acute coronary syndromes?