Nine canine and 30 rat-to-rat long surviving heterotopic liver homografts and six canine heterotopic liver autografts were examined for histopathological changes. The picture of a mixed cardiac and portal cirrhosis, metallaxis of lobular architecture, and congestive bridges were more frequent in the canine heterotopic graft than in the recipient’s own liver or in orthotopic liver grafts, suggesting that unfavorable hepatic venous outflow conditions can influence the late outcome of auxiliary liver transplantation. Optimal hemodynamic conditions can be established by insertion of the graft as proximally as possible by means of a very short vena cava cuff, and by a wide outflow anastomosi