Enzyme‐Treated Bovine Arterial Heterografts, II: In Vivo Assessment in the Dog

An assessment of bovine carotid arterial heterografts was made following their implantation into the thorocic aorta of the dog. Untreated arteries and enzyme‐treated arteries obtained from two sources were studied. Macroscopic, microscopic and tensiometric studies of the grafts were made after their removal from the dogs. Untreated arteries showed a high incidence of rupture and aneurysm formation. However, enzyme‐treated heterografts prepared in our laboratory also showed an unsatisfactory high incidence of degenerative rhanges. In contrast, enzyme‐treated vessels prepared commercially showed no macroscopic evidence of degenerative changes over an average period of five and a half months. Microscopic examination showed that both treated and untreated grafts became encased in dense fibrous tissue, but that the inflammatory response in the wall was considerably less in the treated grafts. Tensiometry revealed a marked increase in the strength of all grafts after implantation when compared with the strength of similar ungrafted vessels.