Myocardial Scar and Cardiac Biomarker Levels as Predictors of Mortality After Acute Myocardial Infarction: A CMR-Based Long-Term Study

<b>Background/Objectives</b>: The extent of myocardial scar, visualized by late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR), is associated with mortality after acute myocardial infarction (MI). However, data on optimal cardiac biomarker cut-off values (e.g., high-sensitivity cardiac troponin T, hs-cTnT) for predicting LGE remain limited. This study aimed to evaluate the predictive value of cardiac biomarkers for LGE and their influence on clinical outcomes. <b>Methods:</b> We included 597 patients who underwent CMR a median of 3 days [interquartile range (IQR) 2-4 days] after MI (407 STEMI and 190 NSTEMI patients), with a median follow-up period of 3.0 years [IQR 1.3-3.5 years]. <b>Results:</b> After adjusting for key variables, maximum cardiac biomarker levels were found to have the strongest correlation with the presence and extent of LGE (<i>p</i> < 0.001). LGE mass and LVEF were the most robust predictors of all-cause mortality (hazard ratio [CI] 1.464 [1.050-2.040], <i>p</i> = 0.025, Harrell's C 0.812; 0.697 [0.491-0.990], <i>p</i> = 0.044, Harrell's C 0.810, respectively). We determined a receiver operating characteristic (ROC) area under the curve (AUC) of 0.73 and an optimal cut-off of 53 g for LGE mass and mortality, with a maximum hs-cTnT cut-off of 7270 ng/L predicting this extent of LGE. <b>Conclusions:</b> In this large cohort of MI patients with three-year follow-up, cardiac biomarker levels showed a strong correlation with the extent of LGE. While absolute LGE mass was associated with mortality, its predictive value was comparable to that of CMR-derived LVEF. These findings should be interpreted cautiously, given the study's observational design, and should be considered hypothesis-generating, underscoring the need for prospective validation.