Crit Pathw Cardiol. 2021 Jun 1;20(2):108-113. doi: 10.1097/HPC.0000000000000249.
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 May 1, 2009 and June 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 2170 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 3 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 versus 63.4 years with higher left ventricular function 51.6% versus 50.4% with less likelihood of prior myocardial infarction 4.1% versus 15.5% or congestive heart failure 2.7% versus 6.3% (P < 0.05). Compared with 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, angiotensin-converting enzyme inhibitor/angiotensin receptor blockers, 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.