Increased Use of Split Liver Transplantation Can Bring More Equitable, Fairer Outcomes for Patients

Transplantation is the only effective treatment for patients with end-stage liver disease, and in the United States, the number of patients awaiting liver transplants far exceeds the number of available donated livers, with median wait times of almost three years. Split liver transplantation (SLT)–a procedure that can save two lives using one liver—increases the benefit from the limited number of livers available but is rarely used in the United States.

In a new working paper, researchers developed a model to help improve decision-making about allocating livers. They concluded that increased use of SLT in the United States could yield significant benefits to patients.

The study, by researchers at Carnegie Mellon University (CMU) and the University of California, San Francisco, appears in Operations Research. 

“As liver shortages persist despite countless efforts to bridge the gap between supply and need, we must take steps to ensure that the livers we have are allocated as efficiently and fairly as possible,” suggests Yanhan Tang, Ph.D, a CMU alumna and Assistant Professor of Information Technology and Operations Management at the Southern Methodist University Cox School of Business, and lead author of the study.

Fewer than 1.5% of livers are split for transplantation in the United States, while the United Kingdom has adopted an “all-split” liver allocation policy, splitting all donated livers except in certain circumstances. Barriers to the increased use of SLT in the United States include logistical difficulties, lack of surgical expertise, geographical challenges, and complexities associated with donor-recipient matching.

Currently, more than 90% of SLTs are performed for children in the United States. 

Since transplant candidates of smaller sizes (e.g., children, smaller adults) typically wait longer for a new liver, SLT could increase the supply of smaller liver allografts, providing more equitable access for these candidates.

In this study, researchers modeled the deceased-donor liver allocation and matching problem, incorporating SLT for the first time. Their model and analysis offer insights into dynamic liver allocation in realistic settings, incorporating philosophical fairness concepts.

Increasing the use of SLT could improve utility and equity compared to the current Organ Procurement and Transportation Network policy and other benchmark policies. Based on current U.S. data, splitting all splittable livers and then allocating the whole/partial livers according to the authors’ model would have nearly optimal results in boosting total quality-adjusted years of life and reducing the total number of patient deaths.

Increased use of SLT may also improve equity by giving transplant candidates who are physically smaller increased access to liver transplants. 

“In addition to encouraging the wider use of SLT, we hope our insights inspire more detailed analyses, including cost-benefit analyses, and foster discussions in the transplant community about further incorporating fairness into allocation rules,” says Sridhar Tayur, Professor of Operations Management at CMU’s Tepper School of Business, who coauthored the study.

“Our model also has uses beyond transplantation,” notes Dr. Tang. “It could be used to address issues such as optimal scheduling of proactive service with dynamic patient health conditions, resource sharing among multiple queueing classes with customer abandonment, and hospitals’ management of patient flow.”

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Summarized from a working paper in Operations Research, “Split Liver Transplantation: An Analytical Decision Support Model” by Tang, YS (Southern Methodist University), Scheller-Wolf, A (Carnegie Mellon University), Tayur, S (Carnegie Mellon University), Perito, ER (University of California, San Francisco), and Roberts, JP (University of California, San Francisco). Copyright 2025. All rights reserved.