Comparison of healing in fresh and preserved arterial allografts in the dog

The use of aortic allografts for the management of vascular prosthetic infe ctions has recently been reintroduced. Impressive results have been obtaine d; however, the possibility of late degeneration remains a major concern. T he healing behavior of aortic allografts, either fresh or preserved, in ant ibiotic supplemented nutrient medium at 4 degrees C for 1 week and used as thoracic aorta substitutes in dogs was investigated after 6 months of impla ntation. Four dogs received a fresh aortic allograft from four different do nors, and four dogs received a preserved allograft from two different donor s. Autografts in two dogs were performed as controls. The in vivo investiga tion was conducted to describe (1) the histological characteristics of the arterial wall, (2) the macroscopic and thrombogenic aspect of the luminal s urface, (3) the integrity of the endothelial lining by scanning electron mi croscopy, and (4) its biochemical function by prostacyclin (PGI(2)) and thr omboxane A(2) (TXA(2)) secretion. immune-mediated reactions directed toward the grafts were measured by sequential screening of donor-specific serum a ntibody development. All donor-recipient pairs of dogs were major hiscompat ibility complex (MHC)-incompatible according to a mixed lymphocyte reaction (MLR) assay. From the results of this study we concluded that although pre served arterial allografts exhibited similar surface characteristics as tho se of fresh allografts in terms of re-endothelialization and long-term graf t function, an elicited immune response, a degenerative process in the medi a, and a hyperplasic reaction in the intima could not be prevented using th is method of preservation.