IMPLANT SITE INFLUENCE ON ARTERIAL PROSTHESIS HEALING - A COMPARATIVE-STUDY WITH A TRIPLE IMPLANTATION MODEL IN THE SAME DOG

Purpose: The purpose of this study was to develop a cost-effective can ine graft healing model that gives information on various implant site s and controls for variable factors between graft locations and betwee n animals and to compare the influence of implant site (retropleural, retroperitoneal, and subcutaneous areas) on arterial graft healing in the same subject under such controlled study conditions. Methods: Five mongrel dogs were studied for 8 weeks, and one was studied for 3 year s. Each received three porous Dacron grafts during the same surgery: a carotid-femoral bypass (C-FB) and interposition grafts in the descend ing thoracic aorta and abdominal aorta. To produce comparable shear st ress calibers of the C-FB and abdominal aorta grafts were 2 mm less th an those of the descending thoracic aorta, and a distal arteriovenous fistula was created to further increase the C-FB flow. For comparable blood aggregation status platelet aggregation was preevaluated and adj usted with antiplatelet agents. Graft now surfaces were assessed for t hrombus-free surface and endothelial-like cell coverage scores. Tissue samples were studied with hematoxylin-eosin, factor VIII/von Willebra nd factor, smooth muscle alpha-actin staining, and scanning electron m icroscopy and transmission electron microscopy. Results: All grafts me re patent. Shear stress for the three grafts and platelet aggregation among the study subjects were comparable. Healing of descending thorac ic aorta and abdomina aorta grafts was similar, but C-FB healing was s low, incomplete, and uneven, with a high incidence of seroma. Eight-we ek and 3-year results were comparable. Conclusions: This model gives b road healing information about the areas where grafts are often implan ted in humans. Eight weeks appears to be a sufficient period to reflec t basic and general healing characteristics. Grafts heal better in the retropleural and retroperitoneal areas than in the subcutaneous tissu es.