Tissue Acceptance of Materials Implanted Within the Circulatory System

Ever since the first attempts to replace blood vessels with a fabric prosthesis, surgeons have tried to understand and control the host's reactions to this foreign object. The natural tendency of the host is to try to incorporate the graft into the body by encapsulating it in living tissue, thus eliminating the interface between the synthetic fibers and the blood. As a result of an increased understanding of the mechanisms involved in this process, continued improvements in materials and construction of grafts have been made in order to optimize the formation of the biologic linings that develop around the synthetic fibers in response to their presence. More recently, the principles applied to the construction of the tubular grafts used in peripheral vascular surgery have been extended to the fabrication of other foreign bodies that have direct contact with the blood stream when implanted. These include prosthetic heart valves, patches used