Liver Transplantation 2022: An Update and What the Future May Hold

Liver Transplantation 2022: An Update and What the Future May Hold

Summary of CME Lecture by Thomas Schiano, MD

1. Main Clinical Topics Discussed

• Evolving epidemiology of liver transplantation indications in the United States
• UNOS/OPTN allocation system reforms (Acuity Circles model, MMAT)
• Indications, contraindications, and timing of transplant referral
• Special populations: NASH, alcohol-related liver disease (ALD), HCC, HIV, HCV
• MELD and MELD-Sodium scoring in candidate prioritization

2. Key Learning Points, Guidelines, and Recommendations

Allocation System Reforms

• Pre-2019 system: 11 geographic regions with 58 OPOs; significant inter-regional MELD score inequities (e.g., transplantation required MELD ≥30 in New York vs. low 20s in other regions)
• May 2019 / Early 2020 – Acuity Circles Distribution Model: Organs allocated to recipients listed within 250 nautical miles of the donor hospital, replacing state/regional geographic boundaries
• MMAT (Median MELD at Transplant): Standardizes exception scores regionally; calculated as median MELD of transplanted patients (excluding fulminant liver failure, pediatrics, and MELD appeals) minus 3

- Example: New York median MELD = 31 → MMAT = 28

• HCC MELD cap reduced from 34 to 28 under the new system to reduce queue advantage
• National Review Board established for non-standard MELD exceptions, replacing subjective regional review

MELD Exception Categories

• Standard exceptions: Decompensated Wilson's disease (Status 1), HCC (6-month waiting period, capped at 28), cholangiocarcinoma, hepatopulmonary syndrome, portopulmonary hypertension
• Non-standard exceptions (require national board review): Refractory ascites, recurrent cholangitis (must include ICU admission + ≥2 bacteremia episodes), failed TIPS, chronic rejection post-transplant

Transplant Referral Indications

Clinicians are strongly encouraged to refer early; key triggers include:

• Sarcopenia/frailty — even with low MELD scores
• Thrombocytopenia (platelets ~20,000) — marker of significant portal hypertension
• Hyponatremia — established milestone in cirrhosis natural history; MELD-Na now formally adopted
• Recurrent hepatic encephalopathy — emerging data suggest chronic neurological sequelae post-transplant
• Minor GFR aberrations — true renal function is systematically underestimated in cirrhosis, particularly in women
• HCC patients undergoing repeated locoregional therapy — progressive hepatic decompensation risk

Contraindications

• Absolute: Severe cardiopulmonary dysfunction, uncontrolled sepsis/occult infection, advanced AIDS, refractory extrahepatic malignancy
• Relative (evolving): Extensive portal vein thrombosis (SMV thrombosis may require multivisceral transplant); alcohol hepatitis (standardization of diagnosis underway)

3. Specific Clinical Data and Statistics Cited

• 15–20% of waitlisted patients die before receiving a transplant, though this rate has modestly declined under the new allocation system
• ~75% of cirrhotic deaths at the speaker's center occur in patients not yet listed — underscoring the true burden of untreated cirrhosis
• Following Acuity Circles implementation (18-month follow-up):

- Deceased donor liver transplants increased by 5%

- Nearly 100 additional simultaneous liver-kidney transplants performed

- Transplant rates increased significantly for higher MELD score patients

- Geographic variability in access decreased at DSA, state, and regional levels

- Median cold ischemic time increased only modestly

- Median donor-to-recipient hospital distance increased; more transplants at 250–500 nautical mile range

• Single-