Abstract
We studied the process of vascular graft calcification through histopathological examination of expanded polytetrafluoroethylene (EPTFE) of different fibril lengths(15-90μm) and Dacron grafts implanted to the carotid arteries of normal dogs. Calcific deposits were observed in a hyalinized connective tissue within the graft wall and a pseudointima 3 months after implantation. Immunohistochemical examination demonstrated that the hyalinized tissue consisted mainly of dense deposits of type I collagen, which might be secreted by fibroblasts infilterating from connective tissues around an outer wall of the grafts. Additionally, EPTFE grafts of longer fibril lengths significantly reduced both hyalinization and subsequent calcification which occured within the graft wall. In conclusion, vascular graft calcification is most frequently associated with an excess deposition of type I collagen fibers, resulting from fibrotic healing in small internodal space of EPTFE grafts.
