Background: Clinical experience with portal vein arterialization (PVA)in liver transplantation is controversial. One reason for this is the lack of standardized flow regulation.The present experiments aimed to establish flow regulation in the arterialized portal vein for heterotopicauxiliary liver transplantation (HALT), to obtain physiological portal blood flow, and to compare thistechnique with orthotopic liver transplantation. Material/Methods: Lewis rats were divided into 7 groups(n=8 transplantations/group). Group: A I-IV: In HALT, the portal vein was anastomosed to the right renalartery using stents with different diameters (0.2, 0.3, 0.4, 0.5 mm). Afterwards, HALT with PVA usingthe stent diameter that had achieved the most physiological portal blood flow (group B II) was comparedwith orthotopic liver transplantation with porto-portal anastomosis (group B III) and to the sham group(B I). Results: After reperfusion, only the 0.3 mm stent resulted in an average blood flow in the arterializedportal vein in HALT which was within the normal range (1.7+/-0.4 ml/min/g liver weight). The parametersof microcirculation and early graft function were significantly better in group B II than in group BIII (functional sinusoidal density: 335+/-48 vs. 224+/-31/cm, diameter of sinusoids: 6.4+/-0.6 vs. 5.2+/-0.6microm, diameter of postsinusoidal venules: 31.1+/-3.3 vs. 25.5+/-2.0 microm, bile-production: 27+/-8vs. 19+/-5 microl/h/g liver weight). Conclusions: Using an optimal stent diameter in HALT with portalvein arterialization, an adequate flow-regulation can be achieved. Avoiding portal hyper- and hypoperfusion,good results for microcirculation and early graft function can be obtained.

Keywords: Arteriovenous Shunt, Surgical, Liver Circulation - physiology, Liver Transplantation - physiology, Microcirculation - physiology, Portal Vein - surgery, Rats, Inbred Lew, Stents, Transplantation, Heterotopic - physiology, Transplantation, Isogeneic