Diagnostic and prognostic validity of different biomarkers in patients with suspected myocarditis

Myocarditis might be associated with increased markers of myocardial injury. However, data on novel biomarkers, such as high-sensitive Troponin T (hs-TnT) or Copeptin, are lacking. This study aimed to determine the diagnostic and prognostic utility of biomarkers in patients with suspected myocarditis. Seventy patients with clinically suspected myocarditis (age 43.4 +/- A 14 years, 76 % male, ejection fraction 36.9 +/- A 17.8) underwent endomyocardial biopsy (EMB) and were followed for 7.5 (2-21) months. At the time of EMB, blood samples to evaluate concentrations of hs-TnT, Copeptin, NT-proBNP and mid-regional pro-adrenomedullin (MR-proADM) were collected. According to EMB, 6 patients were diagnosed with acute myocarditis (AM) and 36 patients with chronic myocarditis (CM). In 28 patients, EMB revealed no myocardial inflammation (NM). Acute myocarditis was associated with the highest concentrations of hs-TnT compared to other groups (AM 262.9 pg/ml (61.4-884.2); CM 20.4 pg/ml (15.6-20.4); NM 19.5 pg/ml (13.8-50.7); p < 0.0001). No significant differences existed in the Copeptin, NT-proBNP, and MR-proADM concentrations between the groups. The concentration of hs-TnT was significantly higher in myocarditis when myocardial viral genome was detected (37.4 pg/ml (21.9-163.6) vs. 20 pg/ml (14-44.4); p = 0.042). During follow-up, only NT-proBNP in the highest quartile (> 4,225 ng/ml) was predictive for cardiac death or heart transplantation (hazard ratio 9.2; 95 % confidence interval 1.7-50; p = 0.011). Biopsy-proven acute and viral myocarditis is associated with elevated concentrations of hs-TnT. Elevated hs-TnT is highly suggestive of acute myocarditis, if other causes of increased myocardial necrosis markers such as myocardial infarction have been systematically excluded.