Prevalence, Clinical Factors, and Outcomes Associated with Myocardial Infarction with Non-Obstructive Coronary Artery (MINOCA).

BACKGROUND Myocardial infarction with nonobstructive coronary arteries (MINOCA) is an underrecognized clinical problem in patients presenting with acute coronary syndrome. Various clinical disorders lead to MINOCA thus making treatment and diagnosis a challenge. We aimed to compare the clinical factors and outcomes of patients with MINOCA versus obstructive disease (myocardial infarction due to coronary artery disease [MI-CAD]) in a largely rural health system. METHODS Between 5/01/2009 -6/24/2019, all consecutive ST-segment elevation myocardial infarction patients at Essentia Health were prospectively examined. We categorized patients into MI-CAD (obstructive plaque ≥50% with revascularization) or MINOCA (obstructive plaque <50% with exclusion of other alternative cause). Outcomes included 30-day and 1-year all-cause mortality, 30-day all-cause readmission and 30-day cardiac readmission. RESULTS There were 2,170 patients included in the study; 2097 (96.6 %) had MI-CAD and 73 (3.4%) met the definition of MINOCA. Within the MINOCA group, the three most common presentations were: supply-demand mismatch (28.8%), spontaneous coronary artery dissection (9.6%), and other etiology (60.3%). Only 10 (13 %) MINOCA patients had cardiac magnetic resonance imaging studies obtained within 6 months. MINOCA patients were younger 61.6 years vs 63.4 years with higher left ventricular function 51.6% vs 50.4% with less likelihood of prior myocardial infarction 4.1 % vs. 15.5% or congestive heart failure 2.7% vs. 6.3%; (p<0.05). Compared to MI-CAD patients, MINOCA patients had similar 30-day mortality (7.1% vs. 8.2%; p=0.70), 1-year mortality (10.4% vs. 8.2 %; p=0.55) and 30-day cardiac readmission (8.7 % vs. 9.6%; p=0.29). MINOCA patients were less likely to be discharged on aspirin, betablockers, ACEi/ARB or statins (p<0.05). CONCLUSION Though there was no difference in readmission and mortality between MINOCA and MI-CAD; use of secondary-prevention medications and cardiac rehabilitation referral was low in MINOCA patients. Prospective studies will be relevant to assess effective medical therapy to improve outcomes in MINOCA patients.