Fibrinogen-to-albumin ratio as a novel biomarker for risk assessment in clinically suspected acute myocarditis

Background: Acute myocarditis typically follows a benign course, but fatal complications may occur in fulminant cases. Evaluation is based on clinical, laboratory, and imaging parameters. We aimed to assess the prognostic value of the fibrinogen-to-albumin ratio (FAR) in patients with clinically suspected myocarditis. Methods: Echocardiographic, laboratory, and clinical parameters were obtained from patients with clinically suspected myocarditis. We assessed the correlations between troponin, albumin, fibrinogen, FAR, left ventricular ejection fraction (LVEF), and complications during the index hospitalization. Repeat echocardiography was performed in patients with reduced LVEF. Several potential factors were tested for their ability to predict LVEF recovery. Results: A total of 118 patients were included (80 % male; median age, 35 years; mean LVEF, 55 %). Median troponin level was 2558 ng/L, and the median fibrinogen-to-albumin ratio (FAR) was 120. In 38 patients (32 %), LVEF was reduced; among them, 15 (39 %) had persistently reduced LVEF on repeat echocardiography. Troponin levels and FAR were inversely correlated with reduced LVEF (r = -0.28, p = 0.002 and r = -0.31, p = 0.001, respectively). FAR remained an independent factor after adjustment for age and sex. Neither troponin nor FAR was associated with persistently reduced LVEF on follow-up echocardiography. In addition, high FAR was not correlated with longer length of stay (LOS) (p = 0.07), readmissions (p = 0.29), or complications during hospitalization (p = 0.22). Conclusion: FAR is associated with reduced LVEF and may reflect disease severity in clinically suspected myocarditis; however, it does not appear to be useful for long-term prediction.