Liver transplantation for maple syrup urine disease: A global domino effect

Domino transplantation for pediatric liver recipients: Obstacles, challenges, and successes

BACKGROUND

Domino liver transplantation aims to address the need to increase the liver donor supply. In a domino liver transplant, the domino recipient receives the explanted liver from the recipient of a traditional liver transplant. The domino donor typically requires liver transplant to correct a metabolic disorder; the explanted liver thus has a single gene defect but otherwise normal structure and function.

METHODS

In this review, we detail the history of domino liver transplantation, appropriate domino donor indications, the technical advances to the surgical approach, current outcomes, and future opportunities.

RESULTS

Development of de novo disease in the domino recipient has relegated adult domino liver transplant to be considered a source of marginal donor livers. However, pediatric domino liver transplant has leveraged certain metabolic disorders, especially maple syrup urine disease, in which the liver enzyme deficiency can be compensated by the systemic presence of sufficient enzyme. Advances in the surgical aspects of assuring adequate length of vasculature have improved the safety of the procedure in both domino donors and recipients.

CONCLUSIONS

Pediatric domino liver transplant utilizing domino donors with specific metabolic liver diseases should be considered a viable live donor option for children awaiting liver transplant.

Hyperleucinosis during infections in maple syrup urine disease post liver transplantation

Maple syrup urine disease (MSUD) is due to biallelic variants in one of the three genes: BCKDHA, BCKDHB, and DBT. Branched-chain alpha-ketoacid dehydrogenase complex deficiency and elevated leucine, valine, isoleucine and alloisoleucine in body fluids are the results. We report hyperleucinosis during intercurrent illnesses in six patients with MSUD post liver transplantation. Patient charts were retrospectively reviewed. Data was entered into an Excel Database. Literature was reviewed. Six patients with MSUD were included who had post liver transplantation hyperleucinosis during an intercurrent illness. Five had encephalopathy. One received hemodialysis for the management of hyperleucinosis. All patients had unrestricted diet. Additionally, there were five patients (one patient included into the current study) reported in the literature. We suggested management considerations for the follow-up of patients with MSUD post liver transplantation after the first episode of unexplained encephalopathy or signs of acute hyperleucinosis during intercurrent illness due to our clinical experience: 1) Healthy: Unrestricted diet and monitoring of leucine levels; 2) Illness: a) home illness management: increased carbohydrate intake b) illness management at hospital: intravenous dextrose, intravenous lipid and daily plasma amino acid monitoring. We report hyperleucinosis and/or encephalopathy as a rare event post liver transplantation in MSUD as a multicenter case series. Hyperleucinosis and/or encephalopathy may occur in both related and unrelated donor liver transplantation. Based on the long-term follow-up of those patients, these suggested management considerations may be revised as per the patients' needs.

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Patients with MSUD can present with hyperleucinosis during intercurrent illness post liver transplantation.

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Hyperleucinosis in MSUD post liver transplantation can occur in related and unrelated donor liver transplantation.

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Monitoring of patients with MSUD is required after their first episode of hyperleucinosis post liver transplantation.

Ethical Analysis and Policy Recommendations Regarding Domino Liver Transplantation

Due to the widening gap between supply and demand, patients who need a liver transplant due to metabolic disease may be asked to serve as domino liver donors-to have their native liver transplanted into another candidate. We here analyze the ethical problems surrounding informed consent for the implant and explant procedures in transplant candidates who will serve as domino donors, using the case of a child with maple syrup urine disease. We discuss the need for 2 distinct consent processes separated in time to ensure that potential domino donors (or their surrogates) give a truly voluntary consent. We propose a Domino Donor Advocate-based on the concept of the independent living donor advocate to help the patient and/or his or her surrogates consider the risks, benefits and alternatives. Finally, we evaluate the Organ Procurement and Transplantation Network policy regarding "therapeutic organ donation" and propose several modifications to ensure that the decision by the potential domino donor (and/or his or her surrogate) is voluntary and informed.

Recent advances in liver transplantation for metabolic disease

The indications and outcomes of liver transplantation for metabolic disease have been reviewed recently and this short review concentrates on recent developments and advances. Recently recognized metabolic causes of acute liver failure are reviewed and their implications for transplantation discussed. Newly described indications for liver transplantation in systemic metabolic diseases are described and an update is given on the role of auxiliary and domino liver transplantation.