Studies to prolong function of experimental auxiliary liver grafts

Abstract

Four techniques have been used in an effort to prolong function of homografted auxiliary liver placed in the retroperitoneal area of 29 pigs: 1. (a) Immunosuppression 2. (b) Arterialization of both hepatic artery and portal vein 3. (c) Arterialization of portal vein alone 4. (d) Retransplantation after failure of the original graft. Regardless of the vascular supply employed in these experiments, none of these auxiliary livers functioned efficiently more than 4–5 days. Retransplantation provided only temporary prolongation of liver support. Reasons why homografted livers in the orthotopic position outperform heterotopic livers are discussed. Even slight obstruction to hepatic outflow present in the abdominal vena cava may depress graft function as compared to the zero or negative pressure in the hepatic veins at the diaphragm. Intermittent external pressure on the liver is also considered to be a factor. It is concluded that auxiliary livers in the right retroperitoneal space might be acceptable for temporary clinical liver assist but that until they can be made to function for prolonged periods, they will not be longrange benefit.