Prediction of scar and microvascular obstruction after myocardial infarction

Abstract Background Myocardial scar, demonstrated by late gadolinium enhancement (LGE), and microvascular obstruction (MVO) at cardiac magnetic resonance imaging (CMR) are well described risk factors for cardiac events after myocardial infarction (MI). Purpose This study aimed to evaluate the prediction of myocardial scar and MVO based on cardiac biomarker levels. Methods We evaluated 631 patients with CMR 3 days [interquartile range 2-4 days] after myocardial infarction (420 with ST-segment elevation and 211 with non-ST-segment elevation myocardial infarction). Cardiac biomarker levels were measured at admission as well as 8, 16, 24 and 48 hours after percutaneous coronary intervention (PCI). Results A myocardial scar was detectable in 586 patients (92.9%), microvascular obstruction in 170 patients (29.3%). Patients with LGE showed significantly higher peak hs-cTnT levels than those without (3908.2±4374.0 ng/l vs 416.8±426.8 ng/l, p<0.001). A cut-off value of hs-cTnT >688.5 ng/l was a predictor for scar with a sensitivity of 81.7% and a specificity of 84.4%. Patients with MVO showed significantly higher peak hs-cTnT levels than those without (6909.8±5525.1 ng/l vs 2467.1±2993.0 ng/l, p<0.001). A cut-off value of hs-cTnT >1500.0 ng/l was a predictor for MVO with a sensitivity of 92.9% and a specificity of 43.4%. Conclusions Higher peak hs-cTnT levels are strong predictors for the occurrence of myocardial scar and MVO at CMR after MI as risk factors for future myocardial events. We propose the new cut-off value of hs-cTnT of >688.5 ng/l within 48 hours after PCI for prediction of myocardial scar and hs-cTnT of >1500.0 ng/l for prediction of MVO. This could be used as a screening tool for post-myocardial infarction patients, who may benefit from further evaluation using CMR.