Waitlist Outcomes for Exception and Non-exception Liver Transplant Candidates in the United States Following Implementation of the Median MELD at Transplant (MMaT)/250-mile Policy

Transplantation. 2024 Aug 1;108(8):e170-e180. doi: 10.1097/TP.0000000000004957. Epub 2024 Mar 29.

Abstract

Background: Since February 2020, exception points have been allocated equivalent to the median model for end-stage liver disease at transplant within 250 nautical miles of the transplant center (MMaT/250). We compared transplant rate and waitlist mortality for hepatocellular carcinoma (HCC) exception, non-HCC exception, and non-exception candidates to determine whether MMaT/250 advantages (or disadvantages) exception candidates.

Methods: Using Scientific Registry of Transplant Recipients data, we identified 23 686 adult, first-time, active, deceased donor liver transplant (DDLT) candidates between February 4, 2020, and February 3, 2022. We compared DDLT rates using Cox regression, and waitlist mortality/dropout using competing risks regression in non-exception versus HCC versus non-HCC candidates.

Results: Within 24 mo of study entry, 58.4% of non-exception candidates received DDLT, compared with 57.8% for HCC candidates and 70.5% for non-HCC candidates. After adjustment, HCC candidates had 27% lower DDLT rate (adjusted hazard ratio = 0.68 0.73 0.77 ) compared with non-exception candidates. However, waitlist mortality for HCC was comparable to non-exception candidates (adjusted subhazard ratio [asHR] = 0.93 1.03 1.15 ). Non-HCC candidates with pulmonary complications of cirrhosis or cholangiocarcinoma had substantially higher risk of waitlist mortality compared with non-exception candidates (asHR = 1.27 1.70 2.29 for pulmonary complications of cirrhosis, 1.35 2.04 3.07 for cholangiocarcinoma). The same was not true of non-HCC candidates with exceptions for other reasons (asHR = 0.54 0.88 1.44 ).

Conclusions: Under MMaT/250, HCC, and non-exception candidates have comparable risks of dying before receiving liver transplant, despite lower transplant rates for HCC. However, non-HCC candidates with pulmonary complications of cirrhosis or cholangiocarcinoma have substantially higher risk of dying before receiving liver transplant; these candidates may merit increased allocation priority.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Carcinoma, Hepatocellular* / mortality
  • Carcinoma, Hepatocellular* / surgery
  • End Stage Liver Disease* / diagnosis
  • End Stage Liver Disease* / mortality
  • End Stage Liver Disease* / surgery
  • Female
  • Humans
  • Liver Neoplasms* / mortality
  • Liver Neoplasms* / surgery
  • Liver Transplantation* / adverse effects
  • Liver Transplantation* / mortality
  • Male
  • Middle Aged
  • Patient Selection
  • Registries*
  • Risk Assessment
  • Risk Factors
  • Time Factors
  • Tissue and Organ Procurement
  • Treatment Outcome
  • United States / epidemiology
  • Waiting Lists* / mortality