20 Ischaemic late gadolinium enhancement in patients with myocardial infarction and no obstructive coronary arteries

Introduction Myocardial infarction with no obstructive coronary arteries (MINOCA) occurs in approximately 1 in 9 presentations with acute coronary syndrome. Cardiac MRI is guideline indicated in the investigation of aetiology for MINOCA which includes a spectrum of pathophysiology, for which there is no evidence-based therapy. The presence of ischaemic late gadolinium enhancement is prognostic in myocardial infarction and represents irreversible myocardial damage. However, factors predicting the likelihood of ischaemic late gadolinium enhancement in patients with MINOCA are unclear. Materials and Methods The overall aim is to undertake a prospective, registry-based clinical trial in MINOCA [NCT05198791]. Specific aims (1) assess the feasibility of enrolling patients during acute NHS care into a therapeutic trial, (2) in all-comers (registry), undertake multisystem phenotyping using objective, quantitative methods, (3) in patients stratified by invasive evidence of coronary microvascular dysfunction (PressureWire XTM, Abbott), randomise (1:1) to a vasculo-protective intervention (eplerenone 25–50 mg daily for 6 months) or treatment as usual, (4) quantify NT-proBNP (primary outcome, trial), patient reported outcome measures and clinical outcomes at baseline, 30 days and 6 months. Cardiac function and pathology are assessed (<14 days) using multiparametric cardiac MRI (CMR, Siemens AVANTO 1.5T). Late gadolinium enhancement (LGE) patterns are described as ischaemic (sub-endocardial, transmural), non-ischaemic (mid-wall, epicardial), non-pathological (insertion point, septal artery) or no LGE. Results Of 82 patients with CMR data recruited between May 2022 and September 2023 (mean age (SD): 60 (11) years; female (%): 78 (63%), 26 (32%) had ischaemic LGE, 6 (7%) non-ischaemic LGE and 34 (41%) no LGE. Factors associated with ischaemic LGE (vs. non-ischaemic vs. no LGE) included ST-elevation at presentation, left ventricular ejection fraction <55%, lower invasive coronary flow reserve (ischaemic LGE: 3.6 (1.8) vs. non-ischaemic LGE: 6.4 (3.3), P = 0.046) and greater peak high sensitivity troponin (median [IQR] – ischaemic LGE: 804 [272, 3359] ng/L, non-ischaemic LGE: 57 [48, 404] ng/L, no LGE: 216 [56, 490] ng/L; P = 0.003). Discussion The presence of ischaemic LGE on CMR may help to identify patients at greater risk of adverse outcomes [PMID: 37480903]. The StratMed-MINOCA registry-based clinical trial will provide information on integrating stratified medicine within a MINOCA acute care pathway. The randomised trial will provide novel data on whether short-term (6-month) mineralocorticoid receptor antagonist therapy using eplerenone, has cardio-protective effects. Conclusion Ischaemic LGE is common in MINOCA, and associated factors include coronary microvascular dysfunction, peak troponin concentration and left ventricular systolic dysfunction. Acknowledgements Robert Sykes is supported by funding from the British Heart Foundation Centre of Research Excellence (RE/18/6/34217),NHS Greater Glasgow and Clyde Endowment Funding (GN21CA394) and Abbott Vascular. Professor Berry is supported by a British Heart Foundation Centre of Research Excellence award (RE/18/6/34217) and funding from the Chief Scientist Office, UKRI (COVID-HEART, reference MC/PC/20014), EPSRC (EP/N014642/1; EP/S030875/1) and Wellcome Trust. Andrew Morrow and Colin Berry are supported by the Medical Research Council (MR/S018905/1).