How NALLDIG Is Advancing Living-Donor Liver Transplants in North America

Juliet Emamaullee, MD, PhD, chair of the North American Living Liver Donor Innovation Group, discusses topline goals.

The North American Living Liver Donor Innovation Group (NALLDIG) was founded in 2018 by two leaders in the field: John Roberts, MD, at the University of California, San Francisco, and Kim Olthoff, MD, at the University of Pennsylvania. NALLDIG is a consortium for living-donor liver transplant centers in the U.S. and Canada. Its purpose is to share information and work together to advance the state of living-donor liver transplants in North America.

In the early era of living-donor liver transplantation, the Adult-to-Adult Living Donor Liver Transplantation Network (A2ALL) was created to combine experience as programs were starting across North America. This network was eventually supported by the National Institutes of Health and provided foundational knowledge for clinical living-donor liver transplant outcomes.”

Why is it so important to have a North America–focused living liver donor consortium?

“We learned a lot from the experience in A2ALL. However, over the last decade, most major advances in living-donor liver transplant have come out of Asia and the Middle East. In those regions, liver transplants are almost exclusively living-donor transplants.

The problem is that it’s hard to extrapolate information on patients from other regions to patients in North America. For instance, in North America, we face a different set of internal and external constraints, such as different insurance infrastructures, a larger deceased-donor population and donors whose who have a higher average BMI. We can’t just say, ‘Well, in Asia, they’re doing X,Y, or Z.’

NALLDIG allows us to provide practice guidelines and perspectives that are relevant specifically to the patients of North America.”

What are some of the practical ways in which NALLDIG members help each other?

“NALLDIG serves as a forum where we can seek each other’s opinions and advice on complicated cases. We can request feedback from each other about unusual donor or recipient decision-making strategies, or we can conduct larger projects. One ongoing project is examining the role for living-donor liver transplantation in patients with rare liver cancers. No center has enough of these complicated cases to provide a meaningful perspective.

By harnessing our collective experience, we can help establish an evidence-based framework for considering these patients. Right now, there are about 50 such cases across the consortium.

In addition, through NALLDIG, we have explored programs to facilitate donor swapping between centers.”

What are some of the biggest current roadblocks that NALLDIG is helping to address?

“We’ve talked a lot about financial neutrality for donors. In the U.S., there is a lot of variation surrounding insurance coverage for living donors. Currently, being a living liver donor is associated with out-of-pocket expenses that can be a barrier for some. The goal is to promote financial neutrality for donors to give everybody who needs a living-donor liver transplant access to one.

The American Society of Transplant Surgeons (ASTS) has been a driving force in seeking congressional support for the Living Donor Protection Act, which ensures Family and Medical Leave Act protection for living donors and prohibits insurance companies from denying coverage or raising premiums for living donors. Members of NALLDIG have been involved in that effort and are part of the dialogue when ASTS goes to The Hill to advocate on behalf of living donors.

We also focus on identifying and addressing additional insurance barriers. For instance, workup and surgery for a living donor is paid for by the organ recipient’s insurance provider. But what about any complications that happen to the donor afterward? Medicare will cover complications related to living donation for life, but private insurance might only cover complications for one year. So, what if a private-insurance donor gets a hernia in their incision two years later and needs to get surgery for that? Is it covered by insurance or not? These are examples of how our group believes that policies need to be refined.

Similarly, if you have public health insurance like state Medicaid or Medi-Cal, oftentimes there are limits to which transplant centers they contract with. If you are in a state that does not have living-donor liver transplant services, a patient might not have any access to living-donor liver transplantation because their insurance plan doesn’t contract with a center out of state that offers living-donor liver transplants.

This can have a direct impact on outcomes, and it’s especially relevant for children. For pediatric transplant, we have strong data showing that living-donor liver transplants result in the best outcomes for children. About 80% of children in the U.S. are on state Medicaid, and if you are in a state that doesn’t have access to living-donor liver transplant, those kids have zero access to the best option. They cannot receive a partial liver transplant from their mom or dad. In the U.S., there’s about a 10% mortality rate for children waitlisted for liver transplants, which could be preventable if they had better access to living donors.”

One of NALLDIG’s other important functions is to share new information and perspectives about living-donor liver transplants. What are some of the topics the group has written about recently?

“Back in April 2025 at the American Surgical Association Annual Meeting, Dr. Elizabeth King from Johns Hopkins University presented an abstract for a new study on long-term mortality rates among living liver donors in North America performed through NALLDIG. Our analysis showed that mortality following living-donor liver donation in North America is rare, with an average overall incidence of 0.06%, or approximately 1 in 1750 donors. This provides a more accurate reflection of the low perioperative risk of living liver donation, and this information can help increase the number of people who are willing to become living donors.

Other upcoming projects include a position piece on transgendered individuals on hormonal therapy serving as living liver donors. We’ve also studied outcomes in patients who undergo living-donor liver transplant for liver cancer. A new project we’re working on, centered at Keck Medicine, is looking at living-donor liver transplants for patients with rare neoplastic indications. Another topic potentially on the horizon is an industry-sponsored study on the use of GLP-1 drugs to help potential living donors lose weight and reduce fatty liver incidence so that they can donate to their loved one.

Having the infrastructure and platform within NALLDIG allows us to think about clinical trials involving donors that can benefit all of us.”

What needs to be done to increase the prevalence of living-donor liver transplants in North America?

“Right now, the prevalence is still low. In the U.S., living-donor liver transplants represent around 5%-6% of all liver transplant activity. In Canada, it’s about 10%. So, there’s certainly room to grow. To put that in perspective, a high-volume center in the U.S. is doing about 20-25 living-donor liver transplants per year, whereas a high-volume center in the Middle East or Asia is doing about 300 per year.

One of the complications about living-donor liver transplants in the U.S. is that the Scientific Registry of Transplant Recipients (SRTR) benchmarks living-donor liver transplant outcomes against metrics used for deceased-donor transplants. And because there are still so few living-donor liver transplants, the consequence is that the results of every single one of those cases matters heavily. If your program is only doing 10-15 living-donor liver transplants per year, just one or two cases, such as cancer recurrence in one patient with high-risk liver cancer, or if an artery clogged and a patient had to be re-transplanted, can negatively impact your center’s SRTR report. This can reduce a program’s ability to take a risk on living-donor liver transplants and may impact a transplant center’s ability to get insurance contracts. By contrast, in Canada, those results are not tracked in the same way, which enables more innovation.

Finally, we need to raise awareness around living-donor liver transplants in general. I think there are misconceptions about the risks of donating, so a lot of doctors don’t even refer patients for living-donor liver transplants. That’s why having data about the actual long-term mortality risk is critical.”

As chair of NALLDIG, what is your goal for the organization?

“Our approach in NALLDIG is to welcome new centers that want to gain the experience of the more experienced transplant centers. We host calls approximately every other month, and anyone who has an idea for a project can put it on the agenda. One of the things I’ve done as chair is to facilitate data-sharing across all the centers. It’s all centered at Keck Medicine, and for anyone who has an idea and wants to move it forward, we have all the paperwork in place to move it forward quickly.

It’s an honor for Keck Medicine to be the home base for this consortium. It allows us to stay at the forefront of what’s happening in the living-donor liver transplantation field by engaging with everybody within this space.”

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