INCORPORATION OF FIBRONECTIN-IMPREGNATED VASCULAR PROSTHESES IN THE PIG - MICROSCOPE STUDY

An interface near the endothelial extracellular matrix is necessary to augment and maintain endothelial cell attachment. The use of plasma l ectins constitutes one of the present lines of research designed to im prove this interface. We studied the incorporation of 2 series of arte rial prostheses with a diameter of 4 mm and a mean length of 9 cm. The y were implanted in the carotid arteries of adult Europig minipigs. Pr ostheses were of two types: polytetrafluoro-ethylene (PTFE) and knitte d Dacron. Two series of 12 pigs each were used. One was explanted at 3 months and the other at six. Each pig was grafted with one prosthesis impregnated with the plasma components of diluted Fibrogel and one no n-impregnated prosthesis which served as control. The explanted prosth eses and adjacent parts of the carotid were prepared for light or scan ning electron microscopy. Proximal, median and distal segments were cu t and embedded in resin. Collagen distribution was revealed by Milliga n's trichrome stain, and fibrin distribution by Picro-Mallory staining . Macroscopic examination showed discrete periprosthetic adhesion for impregnated prostheses and complete adhesion for non-impregnated prost heses. Scanning electron microscopy revealed a median endothelial cell coating on impregnated grafts whereas the only endothelial cells on n on-impregnated grafts were perianastomotic. On impregnated grafts, Mil ligan's trichrome staining revealed an even collagen distribution. The walls of non-impregnated grafts exhibited capillary cell infiltration s with breaches in the outer structures. In impregnated prostheses, th e absence of such breaches enabled us to postulate that their incorpor ation was better than that of the non-impregnated grafts. The minipig model was hard to handle because of the aggressiveness engendered by r estricted feeding designed to limit weight increases. In general, howe ver, we may justifiably conclude that in this model, the use of plasma lectins improved prosthetic incorporation.