Portal Blood Flow and Liver Regeneration in Auxiliary Partial Orthotopic Liver Transplantation in a Canine Model

Abstract

Functional competition has been shown to lead to a detrimental outcome in auxiliary liver transplantation. We evaluated the interaction in auxiliary partial orthotopic liver transplantation between the native liver and the graft in terms of portal flow and regeneration. The need for diversion of the portal flow to the graft was also assessed. Reduced-size liver grafts were transplanted orthotopically after partial hepatectomy in beagles. There were two groups: the preserved group, where portal inflow to the native liver was preserved, and the ligated group, where it was interrupted. Portal flow was measured serially and liver regeneration was evaluated on postoperative day 5. Functional competition was not observed in the preserved group. On the other hand, ligation of the native liver portal vein had no obviously detrimental effects on the remnant native liver. This leads to the conclusion that the portal vein to the native liver can be safely ligated to prevent functional competition.

Portal Flow Diversion Is Essential for Graft Survival in Canine Auxiliary Partial Orthotopic Liver Transplantation

“…An explanation for the difference with our own results in the heterotopic experiment may be that in the present study the total portal flow was forced into a liver graft comprising about 40% of the total liver weight. According to the results of Yabe's group [8,21], we found no evidence that ligation of the native portal vein had detrimental effects on the native liver supplied by arterial flow only.…”

“…We assume that a hyperperfusion syndrome occurred in which portal inflow exceeded hepatic outflow and this resulted in a relative venous outflow obstruction. Primary ligation of the native portal vein was clinically performed by Kaibori et al [19] and further assessed in an experimental study by Yabe et al [21] without problems of portal hypertension. In the study of Yabe et al 2/7 dogs died before sacrifice at day 5 from unknown causes but histologic findings were not given.…”

Auxiliary partial orthotopic liver transplantation: treatment of acute liver failure in a new rat model

“…Although APOLT has recently found increasing acceptance in many transplant centers for the treatment of ALF, its performance still brings specific problems arising from the complex surgical technique, the functional competition between the transplant and the patient's native liver -which may arise during the postoperative course -and the difficulty of predicting whether the patient's own liver will regenerate [1,3,9,10,12,13,14,15,16,17]. The aim of this study was therefore to develop a model of APOLT in the rat which would be clinically relevant and suitable for investigating the problems that arise in clinical practice.…”

Auxiliary partial orthotopic liver transplantation for fulminant hepatitis: regeneration of the diseased native liver in a pig model1

“…It is of great advantage if the diseased native liver regenerates with its function fully restored, because withdrawal of immunosuppression is then possible. However, many problems still remain to be resolved in the clinical application of APOLT, including (1) portal blood competition between the native liver and the graft, and the necessity of portal blood diversion (3,4); (2) deleterious effects of the necrotic liver on the graft function (5); and (3) limited reliability of predicting regeneration of the diseased native liver before the operation (2,6). To clarify these clinical problems, experimental models using large animals are a prerequisite.…”

“…To clarify these clinical problems, experimental models using large animals are a prerequisite. Previous experimental models have not been entirely satisfactory (3,4), because healthy recipients with normal livers were used. To obtain a clinically relevant model, it is thought essential to perform APOLT on animals with FHF.…”