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World J Hepatol. Aug 27, 2021; 13(8): 830-839
Published online Aug 27, 2021. doi: 10.4254/wjh.v13.i8.830
Evolution of liver transplant organ allocation policy: Current limitations and future directions
Alexander Polyak, Alexander Kuo, Vinay Sundaram
Alexander Polyak, Alexander Kuo, Vinay Sundaram, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States
Author contributions: Sundaram V performed the outline of manuscript and critical revision; Polyak A and Kuo A drafted the manuscript.
Conflict-of-interest statement: The authors report no conflicts of interest in relation to this manuscript.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Vinay Sundaram, MD, MSc, Associate Professor, Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, United States. vinay.sundaram@cshs.org
Received: January 28, 2021
Peer-review started: January 28, 2021
First decision: May 3, 2021
Revised: June 22, 2021
Accepted: July 22, 2021
Article in press: July 22, 2021
Published online: August 27, 2021
Processing time: 204 Days and 6.3 Hours
Abstract

Since the adoption of the model for end-stage liver disease (MELD) score for organ allocation in 2002, numerous changes to the system of liver allocation and distribution have been made with the goal of decreasing waitlist mortality and minimizing geographic variability in median MELD score at time of transplant without worsening post-transplant outcomes. These changes include the creation and adoption of the MELD-Na score for allocation, Regional Share 15, Regional Share for Status 1, Regional Share 35/National Share 15, and, most recently, the Acuity Circles Distribution Model. However, geographic differences in median MELD at time of transplant remain as well as limits to the MELD score for allocation, as etiology of liver disease and need for transplant changes. Acute-on-chronic liver failure (ACLF) is a subset of liver failure where prevalence is rising and has been shown to have an increased mortality rate and need for transplantation that is under-demonstrated by the MELD score. This underscores the limitations of the MELD score and raises the question of whether MELD is the most accurate, objective allocation system. Alternatives to the MELD score have been proposed and studied, however MELD score remains as the current system used for allocation. This review highlights policy changes since the adoption of the MELD score, addresses limitations of the MELD score, reviews proposed alternatives to MELD, and examines the specific implications of these changes and alternatives for ACLF.

Keywords: Model for end-stage liver disease score; Acute-on-chronic liver failure; Regional sharing

Core Tip: Since the adoption of the model for end-stage liver disease (MELD) score for organ allocation in 2002, there have been numerous changes to policy in an effort to make organ allocation and distribution more fair and equitable. This review highlights policy changes since the adoption of the MELD score, addresses limitations of the MELD score, reviews proposed alternatives to MELD, and examines the specific implications of these changes and alternatives for acute-on-chronic liver failure.