TThe liver is one of the few organs that does not need to be transplanted as a whole. It can be divided into parts, with one part going to a person who needs a new liver and the other part going to a second person. Removing the barriers to this procedure, known as a split liver transplant, could reduce the number of deaths from liver failure.
Here’s a real-life example (names have been changed for privacy): Jacob was born with a rare disease that damaged his liver and required a transplant about six months after his birth. At age five, he needed a second transplant, but his mother was told it was unlikely that a pediatric liver of the appropriate size would be available in time. About six months later, on Halloween night 2016, a young man in Rhode Island died of a drug overdose. Two days later, at Boston Children’s Hospital, Jacob received 40% of the man’s liver. Miranda, a woman in her 50s suffering from acute liver failure, received the remaining 60%. Today, Jacob is a healthy and thriving 13-year-old; Miranda is doing well, too.
This best-case scenario could become the rule rather than the exception if split liver transplantation is expanded.
Each year, approximately 2,400 Americans eligible for a liver transplant die on the waiting list or are removed from the waiting list because they are too sick for a transplant.
Because of the liver’s unique ability to regenerate, about 10% of livers from deceased donors can be split. The two recipients have similar long-term outcomes to those who receive a whole liver transplant. But only about 1% of livers from deceased donors in the U.S. are actually split. That means that a conservative estimate would be that over 600 additional lives could be saved each year if split liver transplantation were performed more frequently.
The current restructuring of the U.S. Organ Procurement and Transplant Network (OPTN) provides an excellent opportunity to support shared liver transplantation and its life-saving potential. A 2022 report from the National Academies of Sciences, Engineering, and Medicine identified ways to gradually reduce the number of unused donated organs in the United States, such as requiring transplant centers to ensure surgical staff are ready when organs become available. And President Biden signed bipartisan legislation in September 2023 to make the federally overseen organ allocation system more efficient and accountable.
Discussions about years of life lost usually focus on organs (especially kidneys) that, for one reason or another, are not transplanted while they are still viable. Livers, however, are a special case. The number of discarded organs does not reflect the full extent of liver underutilization, since a successfully transplanted liver could potentially have saved the lives of two people on the waiting list rather than just one.
The potential to save more lives through shared liver transplantation has been recognized and promoted in countries such as Italy, the United Kingdom, and South Korea, which have mandatory sharing within clearly defined parameters. Other countries, such as Australia and New Zealand, have policies that require selected livers to be shared whenever possible. But as we described in Case Western Reserve University’s Health Matrix: The Journal of Law-Medicine, the U.S. organ allocation infrastructure unnecessarily discourages liver sharing.
There are three main obstacles to increasing shared liver transplantation in the United States. Each of these obstacles can be overcome with realistic and carefully planned changes to current legislation:
First, while the United Network for Organ Sharing (UNOS), the nonprofit organization that manages the OPTN under a contract with the federal government, has historically established some criteria for sharing livers offered to transplant programs for individual patients, the actual decision about whether to share is made by the organ recipient’s transplant surgeon. Doctors have a fiduciary duty to their patients and therefore must focus on the best outcome for them, rather than the optimal outcome for liver transplant patients as a whole.
Because a split liver transplant carries a higher risk of complications than a full liver transplant, transplant surgeons rarely choose the split liver transplant unless the full liver is too large for their patient. In the rare cases where a doctor agrees to the split liver transplant, the secondary graft is assigned to a recipient of the same size, usually a smaller person or a child.
Second, performing shared liver transplants can jeopardize a transplant center’s outcomes record and, in turn, its future. Transplant centers and their staff can gain revenue, prestige, and career opportunities by performing clearly successful procedures. Poorer than expected surgical outcomes can have negative consequences, including regulatory enforcement actions and negative publicity.
Although more frequent use of split liver transplants would increase the overall survival rate of patients with end-stage liver disease, the technical complexity during and after surgery may result in additional complications for recipients. Because it is an innovative procedure with evolving outcomes, whose appeal lies in its potential to maximize the number of lives saved rather than maximizing immediate outcomes for a smaller, lucky sample of patients, programs that perform split liver transplants risk being penalized as underperforming due to the higher complication rate.
Third, the prioritization philosophy of the transplant system represents another obstacle to wider adoption of shared liver transplants. The limited number of deceased donor livers available for transplant are generally allocated to people who are seriously ill and who need a new liver immediately and urgently. But the most seriously ill people are often too ill to receive a shared liver and require a whole one instead. If some livers are taken out of the normal allocation process and used for shared liver transplants, this will potentially limit the access of the most seriously ill patients to liver transplants.
To overcome these hurdles, the OPTN should implement a mandatory sharing policy similar to policies already implemented in other countries. The policy would require that deceased donor livers suitable for sharing be offered to transplant programs only as shared transplants. This would not only save more lives, but would also eliminate the inherent conflict between transplant surgeons’ duty of loyalty to their individual patient at the time of organ donation and their desire to help other, similarly situated patients. Mandatory sharing would take the decision about sharing out of surgeons’ hands; their revised role would be to counsel their patients whether or not to accept a shared transplant.
A mandatory sharing policy would need to be flexible to allocate split liver transplants to those who would benefit most from the procedure rather than those who are most seriously ill. However, there should be an exception to mandatory sharing for truly urgent cases of fulminant liver failure. While concerns about the most seriously ill are legitimate, they need to be seen in the right light. Only about one in ten livers is suitable for sharing, so the side effects will be limited to the most seriously ill. Getting more people off the waiting list more quickly may reduce the number of people who ultimately need a full liver transplant.
To encourage transplant centers to perform split liver transplants, data on the success of the procedure should be collected and reported separately from data on whole liver transplants. This approach would give transplant professionals the confidence to perform split liver transplants, knowing that the potential complications associated with this innovative procedure will not be blamed on them or the transplant center.
Jacob and Miranda text each other every holiday and sometimes meet up. Jacob considers Miranda an extra aunt who understands what he’s been through and who shares something very special with him. Jacob’s mother and Miranda are also in touch with the donor’s family, who have told them it gives them some peace to know that a part of their son lives on in the two recipients of his liver and the five recipients of his other organs.
With sensible changes to the current transplant allocation system, there can be many more success stories like those of Jacob and Miranda.
Evelyn M. Tenenbaum is Professor of Law at Albany Law School and Professor of Bioethics at Albany Medical College. Jed Adam Gross is a bioethicist in the Division of Clinical and Organizational Ethics at the University Health Network in Toronto and an Assistant Professor at the Dalla Lana School of Public Health at the University of Toronto.
