Comparison of the ST-Elevation Myocardial Infarction (STEMI) vs. NSTEMI and Occlusion MI (OMI) vs. NOMI Paradigms of Acute MI

Background: The current ST-elevation myocardial infarction (STEMI) vs. non-STEMI (NSTEMI) paradigm prevents some NSTEMI patients with acute coronary occlusion from receiving emergent reperfusion, in spite of their known increased mortality compared with NSTEMI without occlusion. We have proposed a new paradigm known as occlusion MI vs. nonocclusion MI (OMI vs. NOMI). Objective: We aimed to compare the two paradigms within a single population. We hypothesized that STEMI(–) OMI would have characteristics similar to STEMI(+) OMI but longer time to catheterization. Methods: We performed a retrospective review of a prospectively collected acute coronary syndrome population. OMI was defined as an acute culprit and either TIMI 0–2 flow or TIMI 3 flow plus peak troponin T > 1.0 ng/mL. We collected electrocardiograms, demographic characteristics, laboratory results, angiographic data, and outcomes. Results: Among 467 patients, there were 108 OMIs, with only 60% (67 of 108) meeting STEMI criteria. Median peak troponin T for the STEMI(+) OMI, STEMI(–) OMI, and no occlusion groups were 3.78 (interquartile range [IQR] 2.18–7.63), 1.87 (IQR 1.12–5.48), and 0.00 (IQR 0.00–0.08). Median time from arrival to catheterization was 41 min (IQR 23–86 min) for STEMI(+) OMI compared with 437 min (IQR 85–1590 min) for STEMI(–) OMI (p < 0.001). STEMI(+) OMI was more likely than STEMI(–) OMI to undergo catheterization within 90 min (76% vs. 28%; p < 0.001). Conclusions: STEMI(–) OMI patients had significant delays to catheterization but adverse outcomes more similar to STEMI(+) OMI than those with no occlusion. These data support the OMI/NOMI paradigm and the importance of further research into emergent reperfusion for STEMI(–) OMI.