Characteristics and In-Hospital Outcomes of Patients With Myocardial Infarction With Non-Obstructive Coronary Arteries　― Insights From the Real-World JAMIR Database ―

BACKGROUND: Few studies have investigated the clinical characteristics and in-hospital outcomes of patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) using real-world databases in the coronary intervention era. METHODS AND RESULTS: We conducted a retrospective analysis of 22,236 patients (mean [±SD] age 68±13 years, 23.4% female) enrolled in the Japan Acute Myocardial Infarction Registry (JAMIR) between 2011 and 2016. Based on urgent coronary angiography findings, 286 (1.3%) patients were diagnosed as MINOCA, and the remaining 21,950 (98.7%) as MI with obstructive coronary artery disease (MI-CAD). MINOCA patients were characterized by younger age, fewer coronary risk factors, lower rate of ST-elevation myocardial infarction, lower Killip classification, and lower peak creatinine phosphokinase levels than MI-CAD patients. In-hospital all-cause mortality did not differ between the MINOCA and MI-CAD groups (5.2% vs. 5.7%, respectively; P=0.82). Comparing cause-specific mortality, non-cardiac mortality was higher in the MINOCA than MI-CAD group (4.2% vs. 1.6%; P<0.01). Importantly, non-cardiac death was more prevalent among elderly (≥65 years) than younger (<65 years) patients in the MI-CAD group, whereas this trend was not observed in the MINOCA group. CONCLUSIONS: Analysis of the real-world JAMIR database revealed a relatively high prevalence of non-cardiac death among MINOCA patients, underscoring the need for comprehensive management to improve disease prognosis, particularly in younger patients.