Liver allocation exception policies for calculating median model for end-stage liver disease at transplant need to be...

In the United States, since 2019, liver transplant waitlist candidates who are approved for a model for end-stage liver disease exception are awarded points that vary based on geography. The number of points is based on the median model for end-stage liver disease score at transplant minus 3 (MMAT-3) of recipients within a specific area, which has changed over time. However, the median model for end-stage liver disease score at transplant (MMAT) is calculated based only on recipients ≥12 years of age transplanted with a liver from a donation after brain death donor located within 500 nautical miles of the transplant hospital. When the policy was first implemented, the restriction to only these donors had little impact, as they comprised the majority of deceased liver donors. However, with the broader use of donation after circulatory death donors, who represent nearly 40% of all deceased liver donors in the United States, the calculation of MMAT based only on donation after brain death donors has led to a marked difference in the calculated MMAT used for awarding exception points and the actual MMAT. In this viewpoint, we highlight the changes in exception policy, the growing difference between the policy-based MMAT and the actual MMAT, and propose policy changes to ensure allocation rules reflect current practice.