Portosystemic shunt for orthotopic liver transplantation in the rat.

Despite several technical improvements, orthotopic liver transplantation (OLT) in the rat remains the most difficult experimental microsurgical transplant to perform. The short anhepatic phase tolerated by the rat makes it difficult for beginners to perform the suprahepatic and portal vein anastomoses in the limited time available. To overcome this obstacle, we examined the ability of a portosystemic shunt, induced previously by subcutaneous transposition of the spleen (STS), to decompress the portal system during hepatic pedicle clamping and thus prolong the anhepatic phase of OLT in the rat. Effective drainage was shown by the ability of rats subjected to STS 3 weeks previously to survive portal pedicle clamping of 120 min, while normal rats all died after 90 min of clamping. We demonstrated that, in STS rats, OLT performed with an anhepatic phase of 1 hr had 100% survival at 1 week, while this procedure caused 100% death in normal rats. The ablation in STS rats of the drastic pH decrease and appearance of endotoxins seen in the portal blood of normal rats subjected to "OLT-like" clamping corroborated these results. This application of the STS model to the field of OLT has already proved in our laboratory to be extremely useful during the surgical learning phase of liver transplantation in the rat.