A systematic review of biomarkers in the diagnosis of infective endocarditis.

Timely diagnosis of bacterial infective endocarditis (IE) is crucial, as mortality remains high in this severe bacterial infection, currently without any distinct biological markers. Our goal was to evaluate potential diagnostic biomarkers by reviewing current literature. The MEDLINE, Embase and Scopus databases were searched for articles published from 1980 through June 2015 restricted to English, Norwegian, Danish and Swedish. Eighteen studies qualified, providing a review of the most promising candidates for future studies. Several studies are inconclusive, since they are characterized by using improper control groups. Patients with IE have bacteremia, and control groups should therefore be patients with bacteremia without IE. Based on current research, N-terminal-pro-B-type natriuretic peptide (NT-proBNP) alone or in combination with Cystatin C (Cys C), lipopolysaccharide-binding protein (LBP), troponins, aquaporin-9 (AQP9), S100 calcium binding protein A11 (S100A11), E-selectin (CD62E) and VCAM-1 (CD54) and interleukin-6 (IL-6) are potential biomarkers for future studies.