Prevalence, Clinical Features, Treatment, and Outcomes in Patients With Myocardial Infarction With Non-Obstructive Coronary Arteries.

Aim: To study clinical and demographic characteristics, treatment options, and clinical outcomes in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) compared with patients with myocardial infarction with obstructive coronary arteries (MIOCA).

Material and methods: This single-center prospective observational study included 712 successive patients diagnosed with acute myocardial infarction (MI), who routinely underwent direct coronary angiography. Based on the presence of stenosing coronary atherosclerosis, the patients were divided into two groups: MIOCA (coronary stenosis ≥50%) and MINOCA (coronary stenosis <50% without other, alternative causes). Clinical outcomes included in-hospital and long-term overall mortality, and cardiovascular rehospitalization. The median follow-up was 1.5 years.

Results: MINOCA was diagnosed in 73 (10.3%) patients, 37 (50%) of whom were women. The median age of patients with MINOCA was 61 years and in the MIOCA group 65 years. No significant differences in cardiovascular risk factors were found between patients with MINOCA and MIOCA. In 53.4% of cases, the cause of MINOCA was a discrepancy between the myocardial oxygen demand and supply, and in 35.6% of cases, the cause was hypertensive crisis and pulmonary edema. The factors associated with MINOCA included an age ≤58 years, female gender, absence of the ST-segment elevation, absence of areas of impaired local contractility, and presence of aortic stenosis and bronchopulmonary infection. Patients with MINOCA were less likely to be prescribed acetylsalicylic acid, P2Y12 inhibitors, dual antiplatelet therapy, beta-blockers, and statins (p<0.05). Data on long-term outcomes were available for 87.5% of patients (n=623). The prognosis of patients with MIOCA was comparable for in-hospital mortality (1.5% vs. 6.2%; p=0.161) and long-term overall mortality (6.1% vs. 14.7%; p=0.059). Cardiovascular rehospitalizations were more frequent in the MINOCA group (33.3% vs. 21.5%; p=0.042).

Conclusion: The prevalence of MINOCA in our study was 10.3% among all patients with acute MI. MINOCA patients had comparable generally recognized cardiovascular risk factors with MIOCA patients. MINOCA patients had a comparable prognosis for in-hospital and long-term mortality and more often required cardiovascular rehospitalization.