https://doi.org/10.1007/s00392-025-02625-4
1Uniklinik RWTH Aachen Med. Klinik I - Kardiologie, Angiologie und Internistische Intensivmedizin Aachen, Deutschland; 2Fachärztezentrum der Kliniken Südostbayern GmbH Kardiologie Traunstein, Deutschland; 3Evangelisches Krankenhaus Düsseldorf Klinik für Kardiologie Düsseldorf, Deutschland; 4Uniklinik RWTH Aachen Klinik für Diagnostische und Interventionelle Radiologie Aachen, Deutschland; 5Uniklinik RWTH Aachen Labordiagnostisches Zentrum Aachen, Deutschland
Introduction:
Acute myocarditis is a potentially life-threatening condition, particularly prevalent among young patients. Cardiac magnetic resonance imaging (CMR) can visualize myocardial inflammation and confirm the diagnosis non-invasively. Therefore, its application in suspected myocarditis is recommended by national and international guidelines. However, access to CMR might be limited in clinical practice, necessitating optimal patient selection for rapid diagnosis. Currently, there are no specific laboratory tests available for detection or exclusion of acute myocarditis. High-sensitive troponin-T (hs-TNT) represents a well-established biomarker for myocardial damage. In contrast to myocardial infarction where hs-TNT rule-in/rule-out values exist, no cut-off for hs-TNT in patients with suspected acute myocarditis has been defined so far. The aim of this study was to define a hs-TNT cut off value to safely rule out acute myocarditis and to waive CMR.
Methods:
This single-center retrospective study evaluated hs-TNT as a biomarker for acute myocardial inflammation. Between 2010 and 2015, 877 patients with suspected myocarditis underwent CMR. After applying exclusion criteria (Figure 1a), 244 patients were included in the analysis. Hs-TNT levels were measured at timepoint of CMR imaging (mean time to CMR 3.1 days), and CMR was performed using standard protocols for the detection of myocardial inflammation. Acute myocardial inflammation was diagnosed based on the established “Lakte-Louise-criteria”.
Results:
CMR confirmed acute myocarditis in 72 of the 244 patients. Hs-TNT levels were significantly higher in those with confirmed inflammation (mean hs-TNT: 652.9 ± 640.5 pg/ml) compared to those without (19.27 ± 55.48 pg/ml, Figure 1b). Receiver-operating characteristic (ROC) analysis yielded an area under the curve of 0.94 for hs-TNT, indicating strong predictive validity (Figure 1d). To assess hs-TNT cut-off values for predicting CMR outcomes, we calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) (Figure 1c). A reasonable cut-off for exclusion of myocardial inflammation through CMR was established as follows: both a sensitivity greater than 0.9 to reliably identify and an NPV above 0.9 to effectively rule out acute myocardial inflammation should be present. For hs-TNT levels up to 18 pg/ml, both sensitivity and NPV values were above 0.9. Specifically, a hs-TNT level of 18 pg/ml demonstrated a sensitivity of 0.92 and a NPV of 0.96, while a level of 20 pg/ml showed a reduced sensitivity of 0.88 (Figure 1c).
Conclusion:
Our findings suggest that patients with suspected acute myocarditis and hs-TNT levels ≤18 pg/ml exhibit a very low likelihood of myocardial inflammation as detected by CMR. Thus, CMR can be safely omitted in these cases to streamline diagnostic processes effectively.
Figure 1: a: Study design with inclusion and exclusion criteria. b: Comparison of high sensitive Troponin-T (hs-TNT) between patients with (CMR positive) and without (CMR negative) acute myocardial inflammation as detected by CMR, two-sided unpaired t-Test, **** = p<0.0001. c: Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the result of the CMR examination for different hs-TNT cut-off values. d: ROC curve for prediction of positive CMR of hs-TNT (AUC 0.94).