Liver transplantation

Liver transplantation is the surgical replacement of a diseased liver with a healthy whole or partial liver from a donor.[1] It is the definitive treatment for end-stage liver disease, acute (fulminant) liver failure, and selected primary liver cancers.[1][2] The liver is replaced orthotopically, the diseased native liver is removed and the graft placed in its normal anatomic position.[1] The liver's capacity to regenerate enables living-donor and split-liver transplantation, in which a portion of a liver supports a recipient and grows toward full size.[1]

Indications

Common indications include cirrhosis from any cause (for example, metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, and viral hepatitis), acute liver failure, cholestatic diseases (such as primary sclerosing cholangitis and primary biliary cholangitis), certain inherited metabolic disorders, and hepatocellular carcinoma within accepted criteria.[1][2] Candidacy and timing balance the risk of waitlist mortality against operative and immunosuppression risk.

Contraindications

Contraindications include uncontrolled extrahepatic infection, extrahepatic or unresectable malignancy outside accepted criteria, severe irreversible cardiopulmonary disease, and conditions that preclude safe surgery or adherence; active substance use is managed case by case.[1][2]

Allocation: the MELD score

In the United States, most deceased-donor livers are allocated by medical urgency using the Model for End-Stage Liver Disease (MELD) score, a formula derived from laboratory values that predicts short-term mortality without transplantation; pediatric candidates use the analogous PELD score.[3] Higher scores receive higher priority. The current version, MELD 3.0, took effect in the United States on July 13, 2023, and incorporates additional variables (including sex and serum albumin) to improve mortality prediction and reduce disparities relative to earlier MELD/MELD-Na versions.[3] A small number of candidates with acute liver failure receive the highest priority (historically "Status 1A"). Exception scores may be granted for conditions, such as hepatocellular carcinoma, whose mortality risk the laboratory MELD underestimates. Geographic distribution uses acuity circles defined by distance from the donor hospital.[3]

Procedure

Orthotopic liver transplantation involves removing the recipient's liver (hepatectomy) and implanting the donor liver with anastomoses of the suprahepatic and infrahepatic vena cava (or a "piggyback" technique preserving the recipient cava), the portal vein, the hepatic artery, and the bile duct (duct-to-duct or to a Roux-en-Y loop).[1] The operation is technically demanding, and intraoperative hemodynamic and coagulation management are critical.[1]

Living-donor and split-liver transplantation

Because the liver regenerates, a portion can be transplanted: in living-donor liver transplantation (LDLT), a healthy donor gives a lobe or segment; in split-liver transplantation, a single deceased-donor liver is divided between two recipients (commonly an adult and a child).[1] These techniques expand the donor pool and shorten waiting time but add donor risk (for LDLT) and technical complexity. See Living donation.

Complications

Major complications include primary non-function or early allograft dysfunction, hepatic artery thrombosis (a leading cause of early graft loss), portal vein thrombosis, biliary complications (leaks and strictures, the "Achilles heel" of the operation), bleeding, rejection, opportunistic infection, the adverse effects of immunosuppression, and recurrence of the original disease (for example, autoimmune disease or malignancy) in the graft.[1][2] See Transplant immunology.

Outcomes

Liver transplantation offers good long-term survival for most indications, with outcomes depending on the underlying disease, recipient condition, and graft quality.[1] The liver is somewhat less immunologically vulnerable than other solid organs, and some recipients can be maintained on relatively modest immunosuppression. National and program-specific outcomes are published by SRTR and OPTN; consult these for current, dated figures.

History

Thomas Starzl performed the first human liver transplants in the 1960s, with the first extended survivors later in that decade; the operation became broadly successful with improved immunosuppression (notably ciclosporin) and surgical technique in the 1980s.[4] MELD-based allocation was adopted in the United States in 2002, replacing waiting-time-based priority with an objective urgency score, and has since been refined to MELD-Na and MELD 3.0.[3]

See also

• Organ transplantation · Living donation · Deceased donation
• Transplant immunology

References

• Liver Transplantation. StatPearls. NBK559161. https://www.ncbi.nlm.nih.gov/books/NBK559161/
• MedlinePlus. Liver transplant. https://medlineplus.gov/ency/article/003006.htm
• HRSA/OPTN. Updates to medical urgency scoring for liver transplant candidates (MELD 3.0; effective July 13, 2023). https://www.hrsa.gov/optn/news-events/news/updates-medical-urgency-scoring-liver-transplant-candidates-effect ; OPTN MELD calculator. https://optn.transplant.hrsa.gov/data/allocation-calculators/meld-calculator/
• U.S. Department of Veterans Affairs Research. The first successful liver transplant (Thomas Starzl). https://www.research.va.gov/research_in_action/First-successful-liver-transplant.cfm