The role of left ventricular ejection fraction grade in differentiating outcomes of Non-ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction

Abstract Background Since there is a lack of studies comparing Non-ST-segment elevation myocardial infarction (NSTEMI) and STEMI outcomes based on left ventricular ejection fraction (LVEF), we initiated this research. Methods From the Korea Acute Myocardial Infarction Registry (KAMIR)-NIH dataset, a total of 9,854 patients were stratified into three LVEF categories: heart failure (HF) with reduced EF (HFrEF, n = 1,250), HF with mildly reduced EF (HFmrEF, n = 2,383), and HF with preserved EF (HFpEF, n = 6,221). Each category was further subdivided into NSTEMI and STEMI groups. The primary clinical endpoint was a patient-oriented composite outcome, encompassing all-cause mortality, recurrent myocardial infarction, repeat coronary revascularization, hospitalization for HF, and stroke. Results After adjustment, in the HFrEF and HFmrEF groups, there was no difference in in-hospital mortality between the NSTEMI and STEMI groups; however, the 3-year mortality was higher in the NSTEMI group. In the HFpEF group, the STEMI group had higher in-hospital all-cause death (p = 0.001) and cardiac death (p 0.001) compared to the NSTEMI group, which was associated with the higher 3-year all-cause death (p = 0.026) and cardiac death (p 0.001) in the STEMI group. After excluding in-hospital mortality, there was no difference in the 3-year mortality between the NSTEMI and STEMI groups in the HFpEF group. Conclusion Given the observed variations in in-hospital mortality and 3-year outcomes across LVEF categories, stratifying NSTEMI and STEMI by LVEF grade serves as a valuable approach for elucidating nuanced differences in clinical outcomes.