[Animal experiment studies of arterialization of the portal vein in liver transplantation using the Göttingen minipig].

Abstract

The aim of the present experimental investigation was to assess the circulatory, biochemical and histopathological consequences of complete portal vein arterialization of the transplanted liver in 'Göttinger' miniature pigs. Orthotopic liver transplantations using a passive portojugular shunt were performed in six male 'Göttinger' miniature pigs. Using an iliac artery segment interposition of the animal donor, the hepatic artery (HA) of the transplant liver was anastomized end-to-end and the portal vein (PA) also united with the internal iliac artery stump end-to-end. The central anastomosis was performed onto the suprarenal aorta. Portal vein blood was drained into the infrahepatic caval vein via an end-to-side shunt (PCS). During the course, the following parameters were determined: arterial blood pressure, venous pressure, cardiac output, electromagnetic blood flow measurements across the HA, PA, and PCS, PA mean pressure, transaminases, partial thromboplastin time and fibrinogen. Liver biopsies and autopsy specimens were investigated. One of six animals died a few hours postoperatively, two of six died after 48 and 72 h, respectively, whereas three pigs survived the scheduled 7 days. The cardiac output fell intraoperatively initially by an average of 20% but had approximately the starting volume of 2.2 l/min at the end of the operation. Although the diameter of the anastomosis was reduced to 4 mm, the flow in the arterialized PA on average was 340 ml/min when the vessel clamp was opened. At the end of operation the mean was 380 ml/min, the interval of measurement being 75 min. The flow across the PCS and the HA were constant during the course. As mechanism for this phenomenon, autoregulation of the liver blood flow on a sinusidal level has been suggested. The biochemical results and the histopathological findings showed no change compared to previous findings in a control group of animals in which liver transplantation was performed by our team. Complete arterialization of the PA is well tolerated in liver transplantation in 'Göttinger' miniature pigs with regard to circulation and liver function in a short-term trial of a maximum of 7 days. Long-term results are still to come.