The liver is one of the few organs that need not be transplanted whole. It can be split into parts, with one part going to one person needing a new liver and the other part going to a second one. Removing barriers to this procedure, known as split liver transplantation, could reduce the number of deaths caused by liver failure.
Here’s a real-life illustration (the names have been changed to protect privacy): Jacob was born with a rare disease that damaged his liver and needed a transplant about six months after he was born. At age five, he needed a second transplant, but his mother was told it was unlikely that a child’s liver of suitable size would become available in time. Approximately six months later, on Halloween night 2016, a young man in Rhode Island died of a drug overdose. Two days later, Jacob received 40% of the man’s liver at Boston Children’s Hospital. 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 also doing well.
This best-case scenario could be the rule rather than the exception with an expansion of split liver transplantation.
Each year, approximately 2,400 Americans who are eligible for a liver transplant die on the waitlist or are removed from it because they have become too sick to receive a transplant.
Because of the liver’s unique ability to regenerate, about 10% of deceased donor livers can be split. The two recipients experience similar long-term outcomes to those receiving whole liver transplants. But only about 1% of deceased donor livers in the U.S. are actually split. This means that, by a conservative estimate, more than 600 additional lives could be saved each year with greater adoption of split liver transplantation.
The current overhaul of the U.S. Organ Procurement and Transplant Network (OPTN) presents a golden opportunity to support split liver transplantation and its life-saving potential. A 2022 report from the National Academies of Sciences, Engineering, and Medicine identified opportunities for incrementally reducing the number of donated organs that go unused in the United States, such as requiring transplant centers to ensure that surgical staff are ready whenever organs become available. And President Biden signed bipartisan legislation in September 2023 to make the federally overseen organ allocation system more efficient and accountable.
Discussion of lost life-years usually focuses on organs (especially kidneys) that, for one reason or another, are not transplanted while they remain viable. Livers, however, are a special case. The rates of discarded organs do not capture the full magnitude of liver underutilization because a liver that has been successfully transplanted could potentially have saved the lives of two people on the waitlist instead of one.
The potential to save more lives through split liver transplantation has been recognized and fostered in countries including Italy, the United Kingdom, and South Korea, which have mandatory splitting policies within clearly delineated parameters. Other countries, such as Australia and New Zealand, have policies to split select livers 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 splitting.
There are three main barriers to increasing split liver transplantation in the United States, each of which can be overcome with realistic and carefully delineated changes to the current legal landscape:
First, while the United Network for Organ Sharing (UNOS), the nonprofit that manages the OPTN under a contract with the federal government, has historically set some criteria for splitting livers offered to transplant programs for individual patients, the actual decision about whether to split is made by the organ recipient’s transplant surgeon. Physicians owe a fiduciary duty to their patients, and must thus focus on the best outcome for them, rather than on the optimal outcome for liver transplant patients as a whole.
Because there is an increased risk of complications with split liver transplants over whole liver transplants, transplant surgeons rarely choose the former unless the whole liver is too large for their patient. In the rare instances when a physician does agree to the split, the secondary graft will be allocated to a size-matched recipient, commonly a smaller individual or child.
Second, performing split liver transplants can jeopardize a transplant center’s outcomes data and, by extension, its future. Transplant centers and affiliated staff stand to gain revenue, prestige, and career opportunities from performing unmistakably successful procedures. Worse-than-expected surgical outcomes can have negative consequences, including regulatory enforcement measures and adverse publicity.
Although greater use of split liver transplants would increase overall survival among people with end-stage liver disease, the technical complexity can result in additional complications for recipients during and following surgery. Because it is an innovative procedure with evolving outcomes, the appeal of which lies in its potential to maximize the number of lives saved rather than maximizing immediate outcomes for a smaller, fortunate selection of patients, programs performing split liver transplants risk being penalized as low performers due to the higher rate of complications.
Third, the transplant system’s prioritization philosophy poses another obstacle to broader adoption of split liver transplants. The limited number of livers from deceased donors that are available for transplant are generally allocated to individuals who are critically ill and have an immediate and urgent need for a new liver. But the sickest people are often too ill to receive a split liver and instead need a whole one. Pulling some livers from the ordinary distribution process to be used for split liver transplantation will potentially reduce the sickest patients’ access to liver transplantation.
To overcome these hurdles, the OPTN should adopt a mandatory splitting policy that is similar to policies already adopted in other countries. The policy would require that deceased donor livers suitable for splitting be offered to transplant programs only as split grafts. This would not only translate to more lives saved, but would also eliminate the inherent conflict between transplant surgeons’ fiduciary duty to their individual patient at the moment an organ is offered and their desires to benefit other, similarly situated patients. Mandatory splitting would take the choice of whether to split out of the surgeons’ hands; their revised role would be advising their patients on whether or not to accept a split graft.
A mandatory splitting policy would have to be flexible to enable split liver grafts to be allocated to those who would benefit most from the procedure, rather than those who are sickest, though an exception to mandatory splitting should be allowed for truly urgent cases of fulminant liver failure. While concern for those who are critically ill is legitimate, it must be kept in perspective. Only about one in 10 livers is suitable for splitting, so the collateral impact on the sickest will be limited, and getting more people off the waitlist sooner may reduce the number who end up in need of a whole 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 whole liver transplants. This approach would give transplant professionals the confidence to embrace split liver transplantation by assuring them that the possible complications associated with this innovative procedure will not be held against them and the transplant center.
Jacob and Miranda text every holiday and sometimes get together. Jacob considers Miranda an extra aunt, one who can understand what he has been through and who shares something very special with him. Jacob’s mom and Miranda are also in touch with the donor’s family, who have told them that it gives them some peace that part of their son is living on in the two recipients of his liver and the five recipients of his other organs.
With reasonable changes to the current transplant allocation system, there can be many more success stories like Jacob’s and Miranda’s.
Evelyn M. Tenenbaum is a professor of law at Albany Law School and a professor of bioethics at Albany Medical College. Jed Adam Gross is a bioethicist in the Department of Clinical and Organizational Ethics at University Health Network in Toronto and an assistant professor in the University of Toronto’s Dalla Lana School of Public Health.