Abstract P202: Prevalence, Factors, And Long-Term Outcomes Associated With Myocardial Infarction With Non-Obstructive Coronary Artery (MINOCA) Diagnosis In A Large Rural Health Care System Cohort

Abstract

Hypothesis: Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) is a common cause of false positive (FP) ST-segment elevation myocardial infarction (STEMI) with associated high morbidity and mortality. Background: MINOCA is an important clinical problem found in patients presenting with acute coronary syndrome. Various clinical disorders lead to a working MINOCA diagnosis and make treatment and diagnosis a challenge for clinicians. MINOCA was recently defined by the American Heart Association (AHA) as those presenting with myocardial infarction with nonobstructive coronary arteries on angiography and no alternative diagnoses for presentation. Methods: Between 5/01/2009 -6/24/2019, all consecutive STEMI patients were prospectively examined and categorized into true positive STEMI activations or false positive STEMI activations (FP-STEMI). FP- STEMI were further categorized into groups based on the presence or absence of obstructive coronary arteries by angiography. Results: We had 472 FP-STEMI patients (42.3% female, median age of 58.9±16.9 years, 53.4% lived rurally) with 152 (31.4%) having evidence of coronary artery stenosis >50%. A secondary cause was identified for an additional 162 (34.3%) patients. Of the remaining FP-STEMI, 82 (2.9%) met criteria for MINOCA and 76 (2.6%) were borderline MINOCA due to not meeting the troponin criteria. Within the MINOCA group, the three most common presentations were: unknown etiology (42.7%), supply-demand mismatch (26.8%), and spontaneous coronary artery dissection (17.1%). The MINOCA group had a higher baseline incidence of dyslipidemia (p=0.037) compared to FP-STEMI and borderline MINOCA and lower smoking compared to borderline MINOCA (p=0.029). At discharge, referral to cardiac rehabilitation was lower (p=0.015) with only 69.7% of MINOCA patients having prescriptions for aspirin, 50% angiotensin converting enzyme inhibitors or angiotensin receptor blockers, 64.5% beta blockers, and 65.8% statins. MINOCA had the highest statin prescription rate compared to borderline MINOCA and secondary (65.8% vs 51% vs 42.1%; respectively p=0.012). There was no significant difference between the mortality of MINCOA patient compared to the FP-STEMI patients. Only 10 (3.5%) had cardiac magnetic imaging studies obtained within 6 months (MINOCA 3.9%, borderline MINCOA 3.9%, and FP-STEMI 2.7% respectively). MINOCA patients had similar 30-day and 1-year mortality to FP-STEMI patients (9.0% vs 12.4% and 12.5% vs 15.2 % 30-day and 1-year respectively; p=0.064 and p=0.107). Conclusion: MINOCA represents a challenging group of patients with high mortality and low rates of medication prescription and cardiac rehabilitation referral.