Life-sustaining canine hepatic autotransplants

Temporary heterotopic auxiliary liver transplantation for fulminant hepatitis B

BACKGROUND/AIMS

Orthotopic liver transplantation has been shown to improve survival in fulminant hepatic failure. However, after orthotopic liver transplantation life-long immunosuppression is necessary and graft complications may occur.

METHODS

We employed heterotopic auxiliary liver transplantation in a 26-year-old man with fulminant hepatic failure due to hepatitis B virus infection.

RESULTS

From a comatose state with seizures and decerebrate posturing, the patient woke up the day after heterotopic auxiliary liver transplantation. The graft functioned sufficiently. After 2 weeks, when peritonitis developed, immunosuppression was stopped since the native liver was recovering as shown by serial HIDA scans, liver biopsies, clotting parameters and serum bilirubin. When severe rejection of the graft developed 2 weeks later, and the peritonitis had been treated successfully, the native liver had recovered sufficiently to allow the graft to be removed. Now, more than 1 year after heterotopic auxiliary liver transplantation, the patient is free from medication and he is immune for hepatitis B virus, his liver tests have returned to normal and he has regained his normal life.

CONCLUSIONS

Temporary heterotopic auxiliary liver transplantation for fulminant hepatitis B is feasible.

New aspects of heterotopic liver transplantation

In this report the history and clinical results of heterotopic liver transplantation (HLT) are reviewed and some special aspects of current research on HLT are high-lighted. The first laboratory experiments on liver transplantation were performed with auxiliary heterotopic grafts. The initial clinical results of HLT, however, were disappointing and orthotopic liver transplantation (OLT) evolved to be the procedure of choice. Of all the patients who received a heterotopic graft before 1980, only two survived. Since 1980, 50 HLTs are known to have been performed on 48 patients. Results of HLTs after 1986 are clearly better than earlier ones, and survival rates come within the range of those reported for OLT. Intraoperative fibrinolysis is found in the anhepatic phase of OLT, something which is absent in HLT. Tissue-type plasminogen activator (t-PA) is said to be responsible for this phenomenon, as well as for the postreperfusion hyperfibrinolysis. Parallel to the hemostatic changes, the intraoperative hemodynamic stability may be impaired by deleterious substances that arise during liver transplantation. Furthermore, the interaction between the two livers, the effect of HLT on portal pressure and hypersplenism, and the possible role of HLT in inborn errors of hepatic metabolism are described. Special attention is given to the treatment of acute hepatic failure. OLT, in an early phase of the disease, negates the possibility of spontaneous recovery, while delay of the decision to transplant may lead to further deterioration of the patient's clinical condition. As the procedure of HLT is reversible, the decision to transplant can be made more quickly. The clinical experience with HLT for acute liver failure is reported in detail.

Auxiliary partial liver transplantation for end-stage chronic liver disease

Auxiliary heterotopic liver transplantation is theoretically attractive because it leaves the recipient's liver in place. The surgical trauma of hepatectomy is avoided, and failure of the graft does not necessarily lead to the death of the patient or a second, emergency transplantation. Another advantage is that matching the body sizes of the donor and the recipient is not mandatory, which increases the number of possible donors. However, previous clinical results of auxiliary liver transplantation have been poor. We performed auxiliary partial liver transplantation in six consecutive patients with end-stage chronic liver disease who were not accepted for orthotopic liver transplantation because they had massive ascites, deficient clotting function, cachexia, or poor pulmonary reserve. The donor liver was transplanted to the right subhepatic region after removal of segments II and III, and it was provided with portal and arterial blood. There were no major changes in hemodynamic measurements during surgery. The mean hospital stay after transplantation was 22.7 days (range, 14 to 29). After a mean follow-up period of 14 months (range, 5 to 23), all patients were alive, with good graft function as demonstrated by scintigraphy, Doppler ultrasonography, and synthesis of clotting factors. From these observations we conclude that auxiliary partial liver transplantation is an attractive alternative to orthotopic liver transplantation in high-risk patients. Its role in other patients who need liver transplants remains to be defined.

Orthotopic nonauxiliary homotransplantation of part of the liver in dogs

An experimental study was carried out investigating the feasibility of using only a portion of a donor liver in orthotopic, nonauxiliary transplantation, establishing a canine model. After being totally hepatectomized, 20 immunosuppressed adult beagles received a 60% donor liver graft, derived from tissue-typed identical littermates. Preservation time was 5 hr. In control experiments, 10 beagles, only half of them immunosuppressed, underwent an operation involving complete liver mobilization, vascular exclusion, cooling of the liver in situ, and a 40% partial hepatectomy with biliary anastomosis. The surgical procedure, including the method of cooling and preservation, is described in detail. Survival rate amounted to 90% for the control group and 50% for the transplanted group, while all surviving dogs were sacrificed 24 wk postoperatively. At sacrifice, the liver weight amounted to the weight of the total native liver at operation. Body weight profiles reflect good general condition of the surviving dogs. No major differences were noted between the immunosuppressed and the nonimmunosuppressed control dogs. No complications were related to the fact that only a partial liver was grafted or left in situ.