New liver distribution system builds on recent transplantation success
The Organ Procurement and Transplantation Network and United Network for Organ Sharing board of directors approved a set of policy amendments designed to reduce geographic differences in liver transplant access and distribution.
“This has always been a problem, but in the last 5 years or so it has become the source of greater and greater conflict. So, there was a movement in the transplant community to try to change the way organs were distributed to mitigate the disparities between supply and demand in different geographic areas,” Jean C. Emond, MD, chair of the Liver Transplantation Special Interest Group at the American Association for the Study of Liver Diseases and vice chair and director of transplant services at Columbia University, told Healio Gastroenterology and Liver Disease . “The baseline state is one of unequal distribution; if you happen to be benefited by that, you’re going to oppose changes in the system — either patients or transplant centers. The patients have the option to move to another area, if that will increase their chances of getting transplanted, but the centers are competing over the business that they get. Centers that were benefiting from the status quo were resisting change and centers that felt disadvantaged were advocating for change.”
The amended policies include the following key provisions:
Liver candidates with a MELD or PELD score of at least 15 will receive additional transplant priority equivalent to 3 points, provided the candidate is within the same donor service area as a liver donor or within 150 nautical miles of a donor hospital in a different service area.
Adult candidates with a MELD score of 32 or higher and pediatric patients with a MELD or PELD score of 32 or higher will receive prioritization for organ offers.
Deceased donor livers will not be subject to expanded donor service areas and proximity circles if the donor was aged 70 years or older or died due to cardiorespiratory complications.
Emond spoke with Healio Gastroenterology and Liver Disease about these new provisions as well as the current barriers and recent improvements in liver transplantation.
Can you describe the current geographic disparities that exist in the U.S. for liver transplant distributions?
In terms of the waitlist, organ distribution — really for decades — has been organized around administrative districts that were created as long as 40 years ago when the National Organ Transplant Act was passed, which required every region to be served by an organ procurement agency. These regions, a lot of them were legacy of arrangements of informal agreements between a group of hospitals, others are states, and some are multiple states. So, they’re all different sizes and different populations; they were never designed for any epidemiologic or demographic purposes.
We have now the supply. The organ donation supply is defined by these administrative regions called DSAs [distribution service areas]. Within each DSA, the transplant centers are active in those DSAs with liver disease. Based on geography, epidemiology, organ donation rates, insurance and access to care, there are all these factors that come together to create imbalances between supply and demand. That’s the state of affairs.
How will this enhanced liver distribution system help mitigate disparities?
Currently, the DSAs vary substantially in size; some just have a million people and some have 13 million people, so the access to livers varies greatly depending on the size of the DSA and the types of patients within the area. The new system now has expanded the opportunity for access to donor organs to either the DSA or a 150-nautical mile around the DSA.
There are a lot of concerns about using an arbitrary 150-mile circle when population density varies so widely across the country, but it’s already a big improvement, particularly in the more populous areas where the arbitrary administrative boundaries from the original maps are now supplemented by these concentric circles.
What concerns exist in the physician community about these new provisions?
Among the 60 or so DSAs, there are pretty big variations in the number of organ donors. Some states or communities have a high rate of organ donation and others have low rates of organ donations. An argument has been made that the transplant centers and patients on waiting lists in areas that have high organ donation should be rewarded and allowed to keep their organs locally, rather than having to share them with other areas, particularly areas that have lower donation rates.
That’s been a big argument: that trying to alleviate disparities without recognizing that some of the disparities are due to organ donation rates is sort of unfair. That’s one objection that’s been raised.
The other objection is that it might increase medical travel. In the original proposal to address disparities, there was a group of either four or eight districts covering the whole country that were mathematically developed to create the least amount of disparities, but that model was rejected because it would have meant an enormous amount of travel and increased costs in terms of moving teams and organs around. Going back to the drawing board after these districts were rejected, they came up with the 150-mile circles that smooths out some very big disparities due to some geographic boundaries without putting a huge amount of travel and logistic burdens on the system.
Will this new system affect distribution with such a scarce organ supply?
Well, it certainly isn’t going to increase the supply and, in fact, there is some unfinished business. The second part of this should be a much heavier hand of regulation and expectation in terms of organ donation around the country. That genie has been popped out of the box in this situation, so I expect a much more vigorous enforcement of organ donation performance by the organ procurement organizations along with this.
In terms of the actual impact on disparities, because every liver transplant patient on the waitlist is ranked in order of severity of disease, you can actually measure the disparities by measuring how high the score needs to go before someone gets to the top of the list. If a very high score is 35 or 40 — at that score patients are about 80% likely to die within 3 months without a transplant —a lower score is around 25. There are parts of the country where you can get transplanted, you can be at the top of the list with a MELD score of 20 or 25, and other places where you must have a MELD of 40 to have a chance to be transplanted. That metric will be easy to monitor to see if that disparity improves.
On the topic of disparities, what can be done to increase living donor donations?
Living donation is routine in kidney transplant; it’s not viewed as a very dangerous thing to do and approximately half of organ donors for kidney transplantation are living donors. In liver, however, it’s a more significant operation. It’s more technically difficult and makes people nervous. In the United States, only about 5% of the total liver transplants performed are done with living donors. In contrast, tens of thousands of living donor transplants are now being done around the world in areas where braindead and deceased donation is not used, such as the Middle East and Asian countries, due to cultural and religious obstacles as well as logistic barriers.
Living donation does need to grow in the United States, and Europe for that matter, but it needs to grow in a way that is perceived as safe. There are lots of opportunities for research to improve living donation, but it’s still a work in progress.
What are the current barriers that could be improved in pediatric allocation?
In adults, the MELD score is based on simple blood tests that predict the risk for dying without transplant reasonably well. That can be supplemented by special awarding of points for certain diseases. So, for the most part, there is a realistic and objective way to compare the urgency of adult patients in need of liver transplant.
In contrast, the ability to stratify the need of children for liver transplants is much harder. A child with liver disease stops growing and the transplants are not being done to help the child survive for 1 year but to hopefully help them survive 30, 40, 50 years — ideally a normal lifespan. In that sense, all children need to be transplanted. Figuring out who’s at risk for dying without being transplanted is neither easy nor practical as a means to decide which children should get a transplant and in what order.
Today, the great majority of children receiving deceased donor liver transplants are getting them based on points that are awarded by committees, rather than any objective scoring system. So, this is a very big problem that has yet to be fixed.
Regarding indications for liver transplant, what recent shifts have occurred?
The fastest growing indication for liver transplant right now is nonalcoholic steatohepatitis and fatty liver disease, which correlates with American health deteriorating and the obesity that’s present.
The good news about the curative treatments for hepatitis C is that it can be used both before, to prevent the need for transplant, as well as after to make sure that the patient survives for a long time. That has been transformative for our field. However, there is still a very large reservoir of chronically-carrying hepatitis C patients who have cirrhosis now who will develop liver cancer during their lifetimes. Those patients will account for a lot of liver transplants.
As far as alcohol, we had simplified the evaluation of alcoholics for transplantation with a simple administrative rule that nobody received a transplant if they hadn’t stopped drinking for 6 months. That rule was very objective, easy to apply, and the insurance companies adopted it quickly. However, the 6-month rule eliminates a lot of people who would do just fine with a liver transplant, even if they stopped drinking less than 6 months ago, and a lot of those who did stop drinking 6 months prior went back to drinking. Overall, the outcomes of liver transplantation for alcohol are pretty good and even when they go back to drinking they can live for years. We’re not happy that they go back to drinking, but it is the reality.
In the last 5 years, there’s been interest in getting away from the 6-month rule and trying to define more patient-specific criteria, such as strong family social support, psychiatric therapy for underlying or associate mental illness, and so forth. A lot of people we might have turned down in the past for alcohol do very well with liver transplantation.
Regardless, we have changing indications, but we still have more people that need transplants than we have organs to give them.
What are the major highlights in liver transplantation and aftercare from this last year?
I would say that continued proliferation of curative hepatitis C therapies have just changed the game and every year we’re understanding better the impact of this on our overall work. It changes the disease burden, it changes the prognosis, and we’re still learning how to use the treatments and when best to treat it.
There’s a very interesting evolution that is the possibility of using donors who are infected with hepatitis C in people who don’t have hepatitis C, knowing that you can cure the hepatitis C afterward. That is just beginning to be investigated and is a very exciting project.
We continue to struggle with liver cancer and the role of liver transplantation for hepatocellular carcinoma. There are far too many people with liver cancer to cure them all with liver transplantation; we have to find out how liver transplantation figures into continued treatment.
The conversations about alcoholic liver disease are just beginning and will continue.
A continued, unmet need in liver transplantation is artificial liver support. That has been on everyone’s to-do list for the last 30 years and there isn’t really much new in that domain.
The other big question in the domain of liver transplantation is the ability to transplant patients without immunosuppressive drugs. There’s still a lot of interest in that — not a lot of progress — but it’s very much on the minds of researchers interested in immunology and liver transplantation. – by Talitha Bennett