Healing parameters of a new albumin-coated knitted Dacron graft

Knitted dacron grafts commercially coated with human albumin were implanted end-to-side between the infrarenal aorta and the bifurcation in 9 growing pigs. Uncoated knitted dacron grafts implanted in 6 pigs served as a control. Grafts were explanted after 4, 8, and 12 weeks and evaluated for neointimal healing, peeling of the inner and outer capsule, extent of neoendothelialization, absorption of the sealant, interstitial infiltration, and perigraft inflammation. Toxicological in-vitro analysis included the evaluation of residual aldehydes and plasticizers. In contrast to the uncoated knitted prosthesis, which rapidly developed a layered neointima with complete neoendothelialization, only islands of neointima were found in albumin-coated grafts after 4 weeks. The neointima remained incomplete at 8 and 12 weeks with scanning electron microscopic evidence of sharply demarcated endothelial areas. No transprosthetic bridging was detectable even after 12 weeks and peeling of the inner and outer capsule was easily provocable. These results outline that the cellular and connective infiltration of the prosthetic wall is compromised unless degradation of the sealant is completed within four weeks: the neointimal development is delayed and graft incorporation fails, leaving the outer capsule unattached.