Abstract

The aim of this work was to determine the criteria for histologically differentiating infectious endocarditis from degenerative valve processes on native valves, bioprostheses and mechanical valves using the SAMBA technique.

The Cardiac Surgery Service of the Center hospital-universities of Timone provided 630 valves. Histological sections stained with hematoxylin eosin saffron (HES) were reviewed. The histological lesions analyzed on slides stained with HES were vegetation, fibrosis and calcifications. Those analyzed after immunostaining were the cells of the inflammatory response (neutrophils labeled with the CD15 antibody, the CD68 macrophages and the CD3 lymphocytes). For endothelial cells, Factor VIII antibody was used. White slides from each case were used to practice immunohistochemistry techniques to mark the different cells of the inflammatory response and the endothelial cells of the neovascular valve.

Of the 630 valve devices examined, 350 were native valves, 200 were bio-prostheses and 80 were mechanical prostheses. Quantitative analysis with the SAMBA technique has shown that infectious endocarditis always has vegetation associated with a multicellular inflammatory infiltrate. In addition, the composition of this inflammatory infiltrate was practically superimposable on the three types of valves. In contrast, the inflammatory response accompanying valvular pathologies other than infectious endocarditis (aortic valve stenosis, chronic rheumatic valvulopathy), was almost composed of mononuclear cell elements. The vegetation was absent. While the phenomena of repair accompanied the two varieties of inflammatory infiltrates.

These results open up new perspectives in the management of patients with infectious endocarditis with negative blood cultures, where the pathologist can, by the technique of quantitative analysis of the valvular histological lesions, minimize the risk of diagnosing an infectious endocarditis because of the evidence of an inflammatory infiltrate.

Keywords: SAMBA Quantitative Analysis, Valvular Devices, Inflammation and Infectious Endocarditis.