Stratified Medicine with Eplerenone for Myocardial Infarction or Injury and No obstructive Coronary Arteries: A Registry-Based Basket Trial

Background Myocardial Infarction with No Obstructive Coronary Arteries (MINOCA) or Nonischemic Myocardial Injury affects approximately 1 in 9 patients presenting with acute coronary syndrome, yet evidence-based therapies are lacking. Coronary microvascular dysfunction is implicated in the pathogenesis of suspected MINOCA, but its prevalence, prognostic implications and treatment are uncertain. The objectives are, first, to assess the prevalence of coronary microvascular dysfunction in patients with suspected MINOCA and, second, to implement endotype-informed stratified medicine involving patients with coronary microvascular dysfunction to treatment with eplerenone, a cardio- and vasculo-protective mineralocorticoid receptor antagonist. Methods This is a prospective, registry-based, multicenter, diagnostic study and nested, randomized, controlled, open-label, blinded-endpoint (PROBE) basket trial. Up to 400 patients with clinically suspected MINOCA and one or more cardiovascular risk factors will be enrolled into a registry-based diagnostic study. Coronary microvascular function will be assessed during invasive angiography using thermodilution. Patients with an index of coronary microvascular resistance (IMR) ≥25 will be randomized 1:1 to eplerenone (25-50 mg daily for 6 months) or standard care without eplerenone (control group) (n=150 randomized). Final endotypes will be centrally adjudicated by a panel of blinded cardiologists. The primary outcome of the diagnostic study is the proportion of patients with IMR ≥25 during index coronary angiography. Secondary outcomes include coronary flow reserve, cardiovascular MRI parameters, patient-reported outcome measures, biomarkers of myocardial fibrosis and vascular inflammation, health outcomes and health economic assessments. The primary outcome of the randomized trial is the within-individual change in NT-proBNP at baseline, 1 month, and 6 months, based on intention-to-treat. Secondary outcomes include mechanistic blood biomarkers and patient-reported outcome measures. Value This registry-based randomized trial will provide novel evidence on endotype-informed secondary prevention therapy with eplerenone for suspected MINOCA.