Bridges to transplantation

Living Donor Liver Transplantation in Acute Liver Failure Patients with Grade IV Encephalopathy: Is Deep Hepatic Coma Still an Absolute Contraindication? A Successful Single-Center Experience

Background

The prognosis of the patients of acute liver failure (ALF) with onset of hepatic coma is often dismal. ALF is a well-accepted indication for liver transplantation (LT) and has markedly improved the prognosis of these patients. However, its role in ALF patients with onset of hepatic coma has never been elucidated before. The aim of our study was to analyze the outcome in patients of ALF with hepatic coma who underwent LT.

Material/Methods

From January 2002 to December 2015, a total of 726 liver transplantations were done at China Medical University Hospital, Taiwan. The hospital database of 59 recipients that underwent LT for ALF was analyzed. Eleven ALF patients with the onset of hepatic coma (grade IV encephalopathy) requiring mechanical ventilatory support were retrospectively analyzed. The patients were sub-grouped in 2 groups depending on the timing of LT after the onset of hepatic coma: Group A had LT within 48 h of onset of coma (n=7) and Group B had LT after 48 h of onset of coma (n=4).

Results

The study cohort (group A and B) comprised 8 males and 3 females, with an average age of 39.63±13.95 years (range, 13 to 63). Ten patients received living donor liver transplantation (LDLT) and deceased donor liver transplantation (DDLT) was done in 1 recipient. All the patients in group A had complete neurological recovery and were extubated within 48 h after LT, whereas extubation was delayed for various reasons for group B patients. At a mean follow up of 36 months (range, 20 to 76 months), the overall survival of all the recipients (group A and B) was 72%. Three-year survival for Group A (n=7) was 85% and for Group B (n=4) it was 50%. There were no acute rejection episodes.

Conclusions

LT is an acceptable modality of treatment for patients of ALF with new onset of hepatic coma. Neurological recovery is expected in all patients if LT can be done within 48 h of onset of hepatic coma without increasing the risk of morbidity. Due to shortage of deceased donor organs in Asia, LDLT can be used proactively, with a success rate comparable to that of non-ALF patients undergoing LT.

Acute liver failure and living donor liver transplantation

Acute liver failure (ALF) is defined by the presence of hepatic encephalopathy due to severe liver damage in patients without pre-existing liver disease. Although the mortality of ALF without liver transplantation is over 80%, the survival rates of ALF patients have improved considerably with the advent of liver transplantation, up to 60-80% in the last decade. Living donor liver transplantation (LDLT), which has mainly evolved in Asian countries where organ availability from deceased donors is extremely scarce, has also improved the survival rate of ALF patients. According to recent reports, the overall survival rate of adult ALF patients who underwent LDLT is 60% to 90%. Although there is still controversy regarding the graft type, the optimal graft volume, and ethical issues of defining the indications for LDLT in ALF patients with respect to donor risk, LDLT has become an established treatment option for ALF in areas where the use of deceased donors organs is severely restricted.

Liver transplantation for acute hepatic failure

There are numerous causes of acute hepatic failure (AHF). Cerebral edema, coagulopathy, renal failure, metabolic disturbances and infection are the main clinical sequelae. Patients with AHF should be stabilized when first encountered and transferred to the nearest liver transplant center, as AHF progresses quickly and is often fatal. There are few adequate medical interventions and care of patients with AHF is supportive until spontaneous recovery ensues. If recovery does not appear to occur, most causes of AHF are well accepted indications for liver transplantation.

Technology insight: liver support systems

Emergency orthotopic liver transplantation (OLT) is currently the only standard treatment for fulminant hepatic failure (FHF). The waiting time for transplantation can exceed a week-using a liver assist device to bridge patients with FHF to OLT might therefore decrease the mortality rate. Several liver support systems have been described, but no system has gained FDA approval or widespread clinical acceptance. Although the results of many experimental and clinical trials are encouraging, the field is still in its initial stages. Using nonbiologic liver support is based on the assumption that several toxins that cause hepatic coma can be removed from the circulation by blood or plasma sorption methods. As these toxins could be involved in many FHF complications recovery without the need for transplantation is the ultimate aim. Biologic liver support uses xenogeneic livers or hepatocytes to support the failed human liver, exploiting biological cell functions, namely detoxification, metabolism, and biosynthesis. The classical nonbiologic dialysis methods could decrease mortality in patients with acute-on-chronic liver failure, but definitive conclusions are impossible to draw because of the small number of patients studied and inadequate follow-up. Larger studies performed in specialty centers should provide conclusive data about the role of the bioartificial liver support system as a possible universal bridge to OLT. This article presents an overview of published experience with liver support systems since the 1960s.