Variability of discharge medical therapy for secondary prevention among patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) in the United States

BACKGROUND: Optimal medical therapy after myocardial infarction with nonobstructive coronary arteries (MINOCA; <50% stenosis) is uncertain. We evaluated variability in discharge prescription of angiotensin-converting enzyme inhibitors / angiotensin receptor blockers (ACEI/ARB) and beta-blockers (BB) to MINOCA patients between hospitals to assess physician equipoise about secondary prevention. METHODS: Patients with MINOCA between 2007-2014 were identified in the NCDR Chest Pain-MI Registry. Those with prior revascularization or missing demographic, angiographic, or medication data were excluded. Analysis was limited to high-volume hospitals with ≥20 MINOCA total discharges. Discharge prescriptions for ACEI/ARB and BB after MINOCA were analyzed for each hospital. Clinical data on left ventricular ejection fraction (LVEF), glomerular filtration rate (GFR), and diabetes mellitus status were extracted to identify other indications for ACEI/ARB or BB. RESULTS: Clinical data were available for 17,849 MINOCA patients, of whom 8,752 (49%) had LVEF <40%, GFR ≤60 mL/min, and/or diabetes. 5,913 patients without one of these indications for ACEI/ARB or BB were discharged from 156 high-volume hospitals. At discharge, ACEI/ARB was prescribed to between 16.0% and 88.8% of MINOCA patients (median 45.6%, IQR 38.0%-56.5%) and BB to between 28.0% and 97.5% (median 74.1%, IQR 64.7%-80.0%). CONCLUSION: There is marked variability between hospitals in the proportions of patients receiving ACEI/ARB and BB after hospitalization for MINOCA, suggesting clinical equipoise about the routine use of these agents. Randomized clinical trials are necessary to establish the benefit of ACEI/ARB and BB to improve outcomes after MINOCA.