Physiologic microcirculation of the heterotopically transplanted rat liver with portal vein arterialization depending on optimal stent diameter.

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 heterotopic auxiliary liver transplantation (HALT), to obtain physiological portal blood flow, and to compare this technique 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 renal artery using stents with different diameters (0.2, 0.3, 0.4, 0.5 mm). Afterwards, HALT with PVA using the stent diameter that had achieved the most physiological portal blood flow (group B II) was compared with 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 arterialized portal vein in HALT which was within the normal range (1.7+/-0.4 ml/min/g liver weight). The parameters of microcirculation and early graft function were significantly better in group B II than in group B III (functional sinusoidal density: 335+/-48 vs. 224+/-31/cm, diameter of sinusoids: 6.4+/-0.6 vs. 5.2+/-0.6 microm, diameter of postsinusoidal venules: 31.1+/-3.3 vs. 25.5+/-2.0 microm, bile-production: 27+/-8 vs. 19+/-5 microl/h/g liver weight).

CONCLUSIONS

Using an optimal stent diameter in HALT with portal vein arterialization, an adequate flow-regulation can be achieved. Avoiding portal hyper- and hypoperfusion, good results for microcirculation and early graft function can be obtained.