The lining of textured surfaces in implantable left ventricular assist devices. An immunocytochemical and electronmicroscopic study.

OBJECTIVE: The aim was to examine and identify some components of biological linings developed upon the textured surfaces of a circulatory assist device. The development of biological linings upon a textured surface circulatory assist device was evaluated in patients implanted for periods ranging from 84 to 132 days. METHODS: Explanted devices were examined macroscopically. Light microscopy, transmission electron microscopy and immunocytochemistry techniques were employed to evaluate the histogenesis of the tissue deposits upon the device surfaces. Visible material was essentially limited to focal areas upon the static housing and the periphery of the pusher-plate diaphragm (Biomer). RESULTS: Microscopy of the linings showed fibrin-rich areas with platelets, monocytes and few spindle-shaped surface cells. Central areas were composed of multiple layers of spindle-shaped cells separated, mainly, by collagen. Giant-cell foreign-body reaction to Biomer fibrils was seen. CONCLUSION: Transmission electron microscopy and immunocytochemistry indicated the presence of at least two cell populations: fibroblasts and smooth muscle-like cells, or 'myofibroblasts'. There was no evidence of endothelial cell presence.