Comprehensive remote myocardium characterisation using T1 mapping in patients with ST-segment elevation myocardial infarction

Abstract Background Myocardial tissue injury due to acute myocardial infarction (AMI) does not only occur in the myocardium that is supplied by the culprit lesion, but can also extend to the remote, non-infarcted myocardium. The prognostic implications of remote myocardium changes assessed by cardiac magnetic resonance (CMR) are not fully understood. The aim was to investigate the prognostic relevance of remote myocardium alterations assessed by CMR T1 mapping (native T1 and extracellular volume (ECV)) in patients after ST-segment elevation myocardial infarction (STEMI). Methods This study analyzed 491 STEMI patients treated with primary percutaneous coronary intervention (PCI) that were included in the prospective MARINA-STEMI study (NCT04113356). CMR imaging was performed 4 (Interquartile range [IQR]: 3-5) days after PCI. CMR images were analyzed for left ventricular (LV) function, standard infarct characteristics as well as native remote T1 and remote ECV. The primary clinical endpoint was the composite of all-cause mortality, re-infarction and new congestive heart failure (Major adverse cardiovascular events, MACE). Results Remote native T1 (median: 1009 [IQR: 979-1044] ms) was associated with female sex, peak NT-pro-BNP levels, peak hs-cTnT elevations, TIMI-risk score, admission Killip class, anterior infarct location, post-interventional TIMI-flow, LV ejection fraction and microvascular injury. Remote ECV (median: 26.37 [IQR: 24.28-29.27] %) was associated with age, female sex, peak NT-pro-BNP levels, diabetes, TIMI-risk score, admission Killip class, anterior infarct location, LV ejection fraction and microvascular injury. Over a median follow-up of 12 months (IQR: 12-13) after STEMI, 42 MACE outcomes occurred. Higher native remote T1-times (1018.5 [IQR: 997.0-1064.0] ms vs. 1007.0 [IQR: 977.0-1041.5] ms, p=0.033) as well as a higher remote ECV-values (28.07 vs. 26.27 %, p=0.009) were observed in patients with MACE. Multivariable Cox regression analysis demonstrated that remote ECV (hazard ratio (HR): 1.53 [confidence interval (CI): 1.07-2.19], p=0.020) but not native remote T1 associated with MACE. Conclusions A comprehensive assessment of the remote myocardium with native T1 and ECV provides prognostic information in a contemporary cohort of low risk STEMI patients. Remote ECV, but not remote native T1, was found to be an independent predictor of MACE.