Clinical Characteristics and Outcome of Patients With Myocardial Infarction With Nonobstructive Coronary Arteries in Japan: Insights From the Miyagi Acute Myocardial Infarction Registry Study.

Abstract

Background: Clinical characteristics and outcomes of patients with myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) are not fully understood, particularly in Japan.

Methods and results: We enrolled a total of 8881 patients with acute MI from the Miyagi Acute Myocardial Infarction Registry Study (2012-2020), with a median age of 69 years. Among them, 239 patients (2.7%) were diagnosed with MINOCA. Compared with those with MI with obstructive coronary artery disease (MI-CAD), patients with MINOCA were more often women, had a higher incidence of non-ST-segment-elevation MI and a lower prevalence of dyslipidemia. Compared with patients with MI-CAD, patients with MINOCA in all age groups (<59, 60-69, 70-79, >80 years of age) had a higher incidence of non-ST-segment-elevation MI. Additionally, those ≤59 years of age were more often women and had a lower prevalence of diabetes and dyslipidemia. In-hospital mortality increased with age in patients with MI-CAD (3.9% for <59 years of age, 5.6% for 60-69 years of age, 8.3% for 70-79 years of age, and 15.2% for >80 years of age; P<0.01), but not in patients with MINOCA (4.5%, 7.4%, 6.0%, and 9.6%, respectively; P=0.36). Compared with patients with MI-CAD, patients with MINOCA had lower in-hospital mortality for Killip class IV (40.7% versus 20.0%; adjusted odds ratio [OR], 0.31 [95% CI, 0.10-0.94]; P=0.04) and renal dysfunction (20.0% versus 7.1%; adjusted OR, 0.29 [95% CI, 0.09-0.96]; P=0.04).

Conclusions: Patients with MINOCA exhibit distinct clinical characteristics and outcomes compared with those with MI-CAD, particularly in terms of age, sex, prevalence of comorbidities, and in-hospital mortality. These findings underscore the importance of tailored clinical approaches for patients with MINOCA.