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Continuous Distribution of Livers and Intestines Concept Paper

eye iconAt a glance


In December 2018, the OPTN Board of Directors approved the continuous distribution framework for allocation of all organs. Continuous distribution will rank waiting list candidates based on points related to various factors, such as medical urgency, post-transplant survival, candidate biology, patient access, and placement efficiency. Continuous distribution will remove the boundaries between classifications and will increase equity for candidates and transparency in the system.

This concept paper provides an overview of the project’s development, progress to date, and next steps for continuous distribution of liver and intestines. The paper requests community feedback that will assist the Liver and Intestinal Organ Transplantation Committee’s work.

Supporting media


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  • From December 2021 to present, the Liver and Intestinal Organ Transplantation Committee worked to identify which attributes should be included in the future allocation system.

Proposed concept

  • Continuous distribution will replace the current classification-based allocation system with a points-based framework. This points-based system will assign a composite allocation score to each candidate.
  • A candidate’s composite allocation score will determine the order that organs are offered to candidates.
  • A candidate’s composite allocation score will consider a combination of donor and candidate characteristics including candidate medical urgency, post-transplant survival, candidate biology, patient access, and placement efficiency.

Anticipated impact

  • What it's expected to do
    • Provide a more equitable approach to matching candidates and donors
    • Remove hard boundaries between classifications that prevent candidates from being prioritized higher on the match run
    • Establish a system that is flexible enough to work for each organ type
  • What it won't do
    • This paper is not a proposed policy change, but will help the Liver and Intestinal Organ Transplantation Committee develop a future policy proposal.

Terms to know

  • Attribute: Attributes are criteria we use to classify then sort and prioritize candidates. For example, in liver allocation, criteria include model for end-stage liver disease (MELD) or pediatric end-stage liver disease (PELD) score, blood type compatibility, distance between donor hospital and transplant program, and others.
  • Composite Allocation Score: A composite allocation score combines points from multiple attributes together. This concept paper proposes the use of composite allocation scores in a points-based framework.
  • Rating Scale: A rating scale describes how much preference is given to candidates within each attribute.
  • Weights: Weights reflect the relative importance or priority of each attribute in the overall composite allocation score. Combined with the ratings scale and each candidate’s information, this results in an overall composite score for prioritizing candidates.

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eye iconComments

OPTN Transplant Coordinators Committee | 09/29/2022

The OPTN Transplant Coordinators Committee thanks the Liver Transplantation Committee for their work and for the opportunity to comment on this concept paper. One member commended the Liver Committee on their work to improve access for liver candidates, and supported the direction the Committee is going with respect to continuous distribution. The member expressed curiosity about the role of post-transplant survival metrics in liver allocation. A member shared that their program has noticed that the six minute walk can often be indicative of post-transplant outcomes, particularly noting that patients with a shorter six minute walk tend to have longer recovery periods with increased risk of complications. The member provided an example that some younger patients on ECMO had aggressive physical therapy, and then walked 150 to 300 feet while on ECMO for the 6 minute walk test, and post-operation would recover faster than another patient with IPF on high flow that could only walk 15 to 20 feet. The member added that the six minute walk can provide some insight in post-transplantation recovery. Another member agreed, sharing that their program utilizes the six minute walk to evaluate frailty in their renal and KP patients, and found that those patients who perform poorly on the six minute walk generally have worse outcomes post-transplant. The member recommended that the six minute walk not only be considered to measure frailty for medical urgency, but also for post-transplant outcomes when considering its use in an allocation model. The member noted the trade-off – there is a point with very frail patients where their medical urgency is very high but their relative outcomes are likely going to be low. One member commented on the objectivity of the six minute walk for lung patients, noting that there are specific certifications for physical therapists when mobilizing ECMO patients, and that few physical therapists in the country actually have this certification. The member pointed out that catering to objectivity could be difficult for most centers who don’t have access to these physical therapists, and that this would need to be considered in attempts to make that test consistent and objective. Another member pointed out patient safety needs to be considered, particularly with respect to mobilizing liver patients to assess frailty, particularly if they have liver disease because of hepatic encephalopathy. A member asked how the Liver Committee plans to operate willingness to accept a split liver as an attribute, and noted that appropriate consideration is needed. The member expressed support as well for HCC stratification, noting that certain HCC patients are more urgent than others. The member finally added that a prior living donor should always get priority as well, regardless of the organ donated.

Medhat Askar | 09/28/2022

In the current allocation policy for Intestine transplant candidates, candidate's biology attributes considered is ABO blood group only but not HLA allosensitization. The role of HLA allosensitization in liver is somewhat controversial, however, the majority of the small number of studies on pre-existing and de novo DSA in intestinal transplants show clear negative impact on clinical outcomes (please see attached 5 abstracts from a pubmed search). To my knowledge, the majority of intestinal transplant programs test for HLA antibodies and attempt to avoid high level of donor specific HLA antibodies (DSA). This means that highly sensitized intestinal transplant candidate may have to wait longer waiting for a donor for which they don't have prohibitively high level of DSA. Therefore, this biological disadvantage should be accounted for in the new continuous distribution framework such as considering the calculated PRA (CPRA) and/or epitope matching between donors and recipients. How much weight to be given to CPRA ought to be balanced by how much other risk factors affect clinical outcomes but not taking HLA allosenstization into consideration altogether would unjustifiably disadvantage these highly sensitized candidates. Thank you for the opportunity to provide comments Medhat Askar, MD, PhD

American Society for Histocompatibility and Immunogenetics (ASHI) | 09/28/2022

ASHI supports the continuous distribution of liver and intestines to align with the NOTA and OPTN Final Rule.

Anonymous | 09/28/2022

During the discussion some attendees were in favor of including frailty but did not have recommendations for how it would be included. Other attendees commented that post-transplant survival is an important attribute to consider to avoid graft loss and re-transplant. One attendee suggested the inclusion of cholangiocarcinoma (not just HCC), and in future versions include DCD donors and use of NRP. Another attendee supported including SDOH.

Anonymous | 09/28/2022

The Living Donor Committee thanks the OPTN Liver & Intestinal Organ Transplantation Committee for their efforts developing this concept paper, Continuous Distribution of Livers and Intestines. The Committee strongly supports incorporating priority for all prior living donors into liver and intestine allocation policy, similar to kidney, pancreas, and lung allocation policies. The Living Donor Committee has discussed the prior living donor priority question at length and concurs that prioritizing prior living donors is both medically and ethically justified. Living donors make a selfless decision to put their health at risk to improve the life of another human being. Though living donation is relatively safe, there is still intrinsic risk associated with organ donation as outlined in OPTN living donor policy, and a lack of systematic collection of data about long-term outcomes. Additionally, as the practice of living donation grows, the Committee recognizes the potential for still unknown risks to be associated with donation. Living donors contribute to the transplant system by donating to one wait listed patient and in doing so, enable transplantation of another waitlisted patient when a deceased organ next becomes available. The Committee supports the societal value of reciprocity to make a donor whole and sending a message to the public that the system values and will stand behind living donors. Additionally, prior living donor priority offers support and assurance to potential donors and the donors' families that the system will take care of them should they ever need a transplant. The Committee strongly supports maintaining high priority for prior living donors and believes this attribute should be given the appropriate weight to maintain their current level of priority in the new continuous distribution system. The Committee emphasizes that living donors should not be valued differently based on their type of donation. The Committee feels living donors make a selfless decision to put their health at risk to improve the life of another human being. Based on this selfless act, judgement should not be placed on what type of organ donation is more “valuable” than another. Historically, prior living donor priority for future transplant was not based upon the type of donation, the motivation, nor the risk to organ specific function for the living donor. The Committee emphasized that VCA and non-VCA living donations are both the act of giving an organ so that someone else can benefit, and as such should be treated equally. The Committee reasons that there is no harm in including VCA living donors within priority for prior living donors due to the exceptionally low likelihood of VCA living donors needing future transplant. The Committee agrees that VCA living donors are living donors, regardless of the state of the field, and they should be advocated for and treated as such.

Anonymous | 09/28/2022

Members of the region offered the committee several things to consider as they continue their work with Continuous Distribution, as it appears more input is necessary along with a more concrete manner in which the system will be implemented. One member stated that they would like the committee to address multi-visceral and intestine transplants with the project. Additionally, another member would like to see DCD liver utilization addressed within Continuous Distribution. It was also noted that the project should avoid all the extra costs, work, or resources that do not help increase transplantation rates. At this early stage of the project it is hard to tell if Continuous Distribution will help lower the organ discard rate. Another member suggested the committee should consider restricting, or setting time limits on, when centers who entertain multiple primary offers are allowed to back-out of an accepted liver offer. One member worries that many of the identified attributes are subjective data points that need specific definitions, for example, frailty. If left too open to determination it could lead to unfair advantages for certain candidates in relation to others.

HonorBridge | 09/28/2022

HonorBridge strongly recommends that the committee analyze and explain the increasing liver discard rate to ensure allocation changes result in maximizing overall organ utilization.

Anonymous | 09/28/2022

The OPTN Pediatric Transplantation Committee thanks the OPTN Liver and Intestinal Organ Transplantation Committee for the opportunity to provide feedback on their Continuous Distribution of Livers and Intestines Concept Paper. The Committee provides the following feedback: The OPTN Pediatric Committee supports the Liver Committee’s concept paper. In terms of attributes, the Committee noted that it is important that the new allocation system includes appropriate consideration and prioritization of pediatric candidates. The Committee expressed that it is critical to involve representatives whose focus is primarily pediatric liver transplant in each stage of developing the continuous distribution plan for livers and intestines to ensure that implications for children - and appropriate attribute definitions and categories for children - are integrated throughout. Additionally, the Committee noted that pediatric transplant candidates should maintain priority even when competing with adult candidates for transplant, and that consistency across organ types for pediatric priority should be strongly considered.

NATCO | 09/28/2022

NATCO appreciates the opportunity to provide the following feedback to the OPTN Liver and Intestinal Organ Transplantation Committee. Overall, the basic principles would appear sound but without modeling, it is difficult to really make an assessment. A perfect model likely does not exist. Some of the attributes may not align. For example, medical urgency (transplanting the sickest) and post-transplant survival (transplanting those who will do better) may be difficult to balance. Giving broad access must be balanced with efficiency as long ischemic times decrease organ quality and costs. Also, the attributes must be tightly defined. • Which attributes should the Committee continue to consider for inclusion in the first iteration of continuous distribution? There appears to be wide acceptance for HCC stratification, consistent with the principle of medical urgency. Similarly, avoiding futile transplants by using likelihood to survive post-transplant is important (but again could be contradictory). Frailty is also an important determinant of survival, yet it is also an indication of medical urgency. As another commenter noted, the transplant community should do more to aggressively “pre-hab” these patients, but as an attribute for continuous distribution, if frailty increased access, that could be a negative incentive and certainly would lead to poorer outcomes. Also, as the committee noted, frailty is somewhat subjective to define. Social determinants of health are somewhat similar as many of these elements are associated with poorer outcomes, but we would be very supportive if the committee could use them to create “opportunity zones” for communities traditionally with less access to liver transplantation. Size matching is an important attribute and would also increase placement efficiency. Blood type also seems to be a relevant attribute. Prior surgery or willingness to accept a split liver do not appear to have enough evidence to support inclusion. Certainly, prioritizing pediatric patients should continue and we would support also giving some priority to prior living donors. HLA sensitization is certainly a barrier for some patients, it would be good to see how it impacts the modeling. • Are there other attributes the Committee should consider that are not included in the list provided above? None that we are aware of. The committee has been very thorough. • Are there any attributes that exist in current policy that should not be included in continuous distribution? No

Society for Pediatric Liver Transplant | 09/28/2022

The Society for Pediatric Liver Transplant (SPLIT) and the North American Society for Gastroenterology, Hepatology and Nutrition (NASPGHAN) appreciate the Liver-Intestine Committee’s work on continuous distribution for liver allocation. In working towards an implementable system of continuous distribution for liver allocation, we encourage the Liver/Intestine Committee to consider: • Consistent priority for the same attributes across organs. In Lung and Kidney CD work to date, their Committees anticipate that pediatric status will account for 15-20% of priority. • Including representation of transplant professionals and patient advocates who focus on the care of pediatric patients in the specific planning for Liver’s Continuous Distribution system. Collaboration with the Pediatric Committee and/or specific addition of Committee or Workgroup members who primarily practice with and care for pediatric liver transplant candidates/recipients is critical to ensure that implications for pediatric patients are considered in each aspect of the Continuous Distribution design. • Availability of pediatric-specific metrics for each attribute: Many of the attributes being considered may need to have different definitions for children. An example is height. Height-for-age percentile, or other criteria based on what the attribute is intended to accomplish, would be more appropriate for children than height alone. In addition, some criteria do not currently have pediatric-specific versions. A key example is frailty; although standardized adult tests exist, there are currently no measures that can be applied to children across the age and developmental perspective. Input from pediatric experts at each stage of designing the system will be helpful to ensure that attributes work as intended for pediatric and adult candidates. • We appreciate the considerable recent work of the Liver/Intestine Committee, Pediatric Committee, SRTR, and UNOS in updating the PELD score, the application of MELD score to adolescents, and Status 1B categories. These updates were made based on review of available evidence and considerable community feedback. We strongly recommend that these updates are carried forward into the Liver Composite Allocation Score. • Pediatric-specific modeling of the new Composite Allocation Score should be included in this planning process. Considering the impact of different attribute scores for children versus adults will be an important consideration for some attributes; for example, particularly after the implementation of Acuity Circles, a significant percentage of children receive liver transplants through national shares. The appropriate priority for placement/proximity efficiency may thus be different for pediatric and adult candidates. • Candidate Blood Type: Evidence from the U.S. and other countries demonstrates that young children less than 2 years of age have comparable outcomes with ABO-incompatible transplants. These are also the children at highest risk of death on the waitlist. The Committee should consider whether children less than 2 years of age, if their center indicates that they would accept an ABO-incompatible transplant, should get the same priority as compatible or even identical blood types. • Willingness to accept a split liver transplant – Priority for transplant candidates for whom an organ acceptance will initiate a split liver transplant, thereby creating 2 transplants for 1 organ – would benefit all candidates. Historically, more than 98% of split liver transplants are initiated by an offer to a child. Many adults are listed as “willing to accept a split liver transplant,” but offers to these adults almost never actually initiate a split liver transplant. To make an attribute truly effective for increasing split liver transplants, one option would be to award this priority to candidates willing to accept a transplant AND likely to actually initiate a split transplant, based on historical data on actual split liver transplants (e.g. candidate age and size, donor characteristics, candidate listing at a center that has performed split liver transplants in the previous 1-2 years). • Exceptions and the NLRB: We agree that redefining standard “exceptions” as established reasons for increased priority that are not reflected in other medical urgency scores (e.g. PELD) or other attributes would be appropriate to include in the composite allocation score design. For children, these groups are small – and often medically heterogenous. Here again, specific input throughout the process from pediatric experts will be critical. o Pediatric candidates, given what a heterogenous population they are, will still need a process for requesting exception points in unique circumstances. We agree that asking centers to classify these requests within existing attribute categories could be helpful. • Donor factors: We agree that donor factors should be considered in the composite allocation score. Specifically, the Liver Committee spent considerable time updating allocation schemes to prioritize children for pediatric donors in the last few years, based on careful evidence analysis. This has improved outcomes for pediatric candidates and recipients and should be retained in design of the Liver Composite Allocation Score.

Anonymous | 09/27/2022

A member commented that the candidate biology component of the score is intended to address limitations a candidate may have accessing a donor due to a specific biologic characteristic that would reduce the potential number of donors available in contrast to candidates without this characteristic, where the small size, blood type and HLA sensitization are the prototypes for this factor. The member pointed out that it is unclear how frailty fits into candidate biology unless it is intended to be a surrogate for size. Since frailty is typically considered to increase urgency and decrease post-transplant survival (i.e. lead to a higher medical urgency score and a lower post-transplant survival score), the recommendation is to model frailty for both of those score components rather than trying to fit frailty into candidate biology which would only have an effect comparable to the medical urgency component. A member emphasized the need to ensure that pediatric candidates retain existing priority in comparison to the existing system. A member supported this paper and said that the data supports it as well. A member inquired if the medical urgency attribute referred to the “sickest” patient receiving priority. The member explained that she doesn’t agree with the “sickest” patient receiving priority as the best use of a donated organ, since the “sickest” patient can have many health issues resulting from their failing organ and those issues may not be resolved with a transplant. This may lead to post-transplant recovery issues and premature graft failure and death. A member explained that post-transplant survival is an important attribute to include in the CAS. The member suggested that some components, such as frailty, could increase an attribute score (medical urgency) and lower another (post-transplant survival). A member opined that if these are weighted equally, how does frailty actually have an impact. Another member pointed out that it is not clear why frailty fits into the candidate biology component, as opposed to contributing to models of urgency or outcome, particularly if objective assessment of frailty is not possible. Another member stated there needs to be consensus on frailty measurements. A member stated that he very strongly agrees that previous living liver donors should have priority when considering attributes. Another member commented that the choice of attributes are all important. Another member pointed out that social determinants of health will be difficult to collect.

Association of Organ Procurement Organizations | 09/27/2022

Please see the attached comment from the Association of Organ Procurement Organizations

View attachment from Association of Organ Procurement Organizations

Anonymous | 09/27/2022

Members of the region voiced support for the concept of continuous distribution for livers, but they offered several suggestions for the committee to consider as they continue with the project. One member noted that many professional transplant societies already collect data around liver transplantation, and the OPTN should reach out to those societies for that data instead of also collecting the same data. Others expressed concern with current air transportation resources. There are a limited number of planes and pilots across the country. The committee is encouraged to be mindful of this reality when considering the weight of travel and proximity efficiency. Another member noted concern with early results from Acuity Circles, suggesting a significant increase in the distance organs have to travel and the associated cost while there have been minimal changes in patient survival or MELD score. Another member encouraged the committee to promote split liver transplantation for pediatric patients within the continuous distribution system, given that the high mortality rate for candidates less than 2 years old. Other members noted that the committee should consider diseases that are not covered in the current system, and wait time needs to be built into the exception system. Lastly, another member expressed strong support with this initiative. This work will promote a more transparent system that patients and providers should understand. The member feels that the attributes that should be included in the first iteration are post-transplant survival, frailty, and prior living donor. The other consideration that the Committee should consider is placement of people with rare or unusual diseases that increases their mortality but does not fit well in this system. There should be ways to be included in this process with broader exceptions.

American Society of Transplantation | 09/27/2022

The American Society of Transplantation (AST) generally supports the approaches outlined in the Continuous Distribution of Livers and Intestines Concept Paper. The AST offers the following comments for consideration as this work continues: •An ideal continuous score-based allocation model must balance not only consideration of waitlist mortality, but also maximize post-transplant outcomes, ensure equitable access to liver transplantation, and consider placement logistics and efficiency. •If frailty is included as a factor, it must be objectively measured and included in both urgency and post-transplant survival estimates. •Optimized prediction of mortality (OPOM) may be superior to MELD/PELD but requires further liver transplant community review. Additionally, it is not known how alterations to MELD (e.g., MELD 3.0) may perform compared to OPOM. •Regarding candidate biology: -ABO compatible blood types should be ranked equally once a threshold medical urgency is reached. -To allow for equitable transplantation, donor-recipient size matching is imperative to ensure smaller adults have the same access to transplantation as larger adults. Again, using a medical urgency threshold, smaller candidates could be prioritized to the smaller donor -It is reasonable to offer additional points to surgically complex or retransplant patients, especially if the candidate initially received a marginal graft. -Because of the uncertainty in the current usage of HLA sensitization in listing practices and the impact of HLA sensitization in liver transplant outcomes, additional study is necessary to establish the benefit of including HLA sensitization in continuous distribution for isolated liver allocation. •Regarding patient access: -The AST supports increasing priority to liver-intestine candidates and recommends reviewing waitlist mortality data to inform whether other multi-organ liver candidates should also receive increased priority. -Pediatric patients should continue to receive priority, and the OPTN should use factors other than age as a proxy to incorporate this priority. The OPTN must evaluate any proposed policy changes to demonstrate a negative impact to pediatric patients is unanticipated. -The AST supports priority for candidates who have been prior living donors. -Prioritizing candidates able to accept a split liver would result in better organ utilization assuming there would be a safety net in place in the rare event retransplant is needed.

View attachment from American Society of Transplantation

Anonymous | 09/27/2022

The Minority Affairs Committee (MAC) thanks the OPTN Liver and Intestinal Organ Transplantation Committee for the opportunity to provide feedback on their Continuous Distribution of Livers and Intestines Concept Paper. The Committee provides the following feedback: The MAC expressed support for the Liver Committee’s concept paper. The Committee encourages the Liver Committee to seek ways to increase equity by identifying Social Determinants of Health (SDoH) attributes and expressed support for the collection of SDoH data in order to measure the impact of continuous distribution on vulnerable populations. The Committee expressed concerns about physicians that may implement therapies in an effort to move their patient up on the list and access a transplant faster, also known as “gaming the system.” The Committee expressed that gaming does not usually favor vulnerable populations and suggested that the Liver committee identify methods to prevent this.

OPTN Ethics Committee | 09/27/2022

The Ethics Committee appreciates the work of the Liver and Intestinal Organ Transplantation Committee in developing this concept paper and for the opportunity to comment on it. The Ethics Committee is very supportive of including social determinants of health factors in the allocation framework. A member suggested considering alcohol use in the context of social determinants of health (SDoH), especially with regard to the rehabilitation services that a patient may not have access to in order to be eligible for transplant. A member emphasized the need to incorporate SDoH data at the outset of these discussions and modeling in order to accurately and successfully build it into the new framework. The SDoH factors would likely have a greater impact and be more easily measured if considered at the outset of the continuous distribution framework as opposed to trying to fit it in years later. A member suggested including an attribute for medically complex patients and provided the example of patients with graft failure who are repeatedly hospitalized for sepsis. The inclusion of this attribute would assist medically complex patients who are chronically ill but do not have a MELD score that reflects their medical urgency. Overall, the Ethics Committee appreciates the opportunity to provide feedback and looking forward to continuing to contribute throughout the development of continuous distribution of livers and intestines.

Anonymous | 09/26/2022

An attendee commented that cost should be considered with the distance/travel attribute. An attendee recommended that attributes should be analyzed for their association to decreased rates of transplantation. A few attendees commented that they think our system is reasonable right now and the focus should be on making it more efficient.

Preston Foster | 09/26/2022

Too complicated, impossible to explain to patients, patients and doctors will not trust this system. Basically an equation to decide organ allocation. I think it will be difficult to determine if patient groups /localities are being discriminated against by such a system. Remedy will be even more difficult implement.

American Society of Transplant Surgeons | 09/26/2022

The American Society of Transplant Surgeons (ASTS) appreciates the opportunity to provide the following feedback to the OPTN Liver and Intestinal Organ Transplantation Committee. Which attributes should the Committee continue to consider for inclusion in the first iteration of continuous distribution? The five attributes listed are consistent. Since Medical Urgency is the primary factor in current allocation, it would be difficult to change that to a less weighted attribute. Are there other attributes the Committee should consider that are not included in the list provided above? In the sub-score for Post-Transplant Survival, the Committee states they are attempting to reduce futile transplants; however, this is difficult to quantify. An idea would be to de-emphasize patients with calculated MELD scores above 40. MELD score is capped at 40, but we recognize it is capped because the benefit of transplant may diminish if the patient is sicker than that. De-emphasizing patients with scores above 40 may reduce futile transplants. In the sub-score for Patient Biology, they are looking for characteristics for difficult to match and complex transplants. Blood type, size mismatch and re-transplants are all appropriate variables. We suggest portal vein thrombosis be an additional variable added to this. In the Placement Efficiency Sub-score, we feel donor factors should be considered for proximity points. Livers from donors aged above 70 and DCD livers cannot tolerate prolonged ischemic times, so recipients closer to the donor should be given additional points. As for social determinants of health (SDH), inclusion is fraught with problems but inclusion of post-transplant survival without consideration of SDH runs the significant risk of further disadvantaging underserved populations. Some form of inclusion in the first iteration is important. Are there any attributes that exist in current policy that should not be included in continuous distribution? Attempts to introduce the HCC stratification score and the OPOM are too complex and as yet untested rigorously enough to introduce these in first iteration of the continuous distribution; HLA matching and sarcopenia scores should also not be included. The HLA matching does not significantly make a difference, and the sarcopenia scoring is very subjective. Similarly, Social Determinants of Health (SDH) are very hard to quantify and will unnecessarily complicate this system if introduced. Further refinement of the MELD score, as has been done in the past, may be more palatable. In the sub-score for Patient Access, "willingness to accept a split liver" is considered one of the variables for priority and we suggest that this score only play into the Composite Score when a split liver is being offered. Any other feedback on the plan to develop continuous distribution of livers and intestines. We are still in the experimental phase of using liver pumps for transport and storage. This may allow for longer ischemic times and use of more marginal organs. This has not yet figured into any calculation of score points. The Committee needs to do an analysis of this for the future.

View attachment from American Society of Transplant Surgeons

Anonymous | 09/21/2022

An attendee suggested that supply and demand should be considered as a factor. Another attendee suggested these attributes should be part of liver offer filters. Overall, they are in favor of the continuous distribution model with one exception – acute liver failure and that re-transplantation should be given priority over all other candidates. Finally, an attendee asked the presenter how the non-HCC exceptions will be incorporated and the presenter answered that these will still go through the NLRB. An attendee suggested that to address comments from various regions, would the committee consider weighting the MELD component differently based upon prevalence of disease. Meaning in an area of high disease prevalence but lower referral, would a MELD score that is lower receive more weight? Finally, an attendee commented that continuous distribution is an important change consistent with NASEM recommendations and committee should think critically of attributes that will maintain this as a candidate/patient focused framework.

Anonymous | 09/20/2022

During the discussion about the concept of continuous distribution of liver and intestines attendees were interested in more information about how PELD would be prioritized and how exceptions would be handled. There were also comments about how the committee would include frailty. One attendee noted that while CD appears to improve equity, they were concerned about whether or not it would increase utilization. Another attendee urged the committee to look into multi-visceral transplants. They added that the current system of placing MVTs from the liver match makes it difficult to get those candidates transplanted. They also urged the committee to look closely at the intestine system and commented that it is out of line of other international TX systems. One attendee recommended treating candidates as pediatrics if they are listed before age 18 with the idea of a congruent system as they age. There was also a comment that the Committee needed broader representation to increase trust in the committee’s intentions and consideration should be given to cost, recovery, complexity and justice that are all at risk with a major new revision in allocation.

Region 2 | 09/13/2022

A member noted their support for the direction the committee is heading, but they will be interested in seeing predictive modeling to better evaluate the project. There was a difference in opinion on the inclusion of post-transplant survival in the list of attributes, with both support and opposition of their inclusion voiced by some in attendance. Another member voiced concern on the inclusion of candidate Social Determinants of Health (SDOH). Adverse SDOH is connected to outcomes and the committee needs to develop a system that tracks and supports patient’s success. The final Continuous Distribution proposal should decrease SDOH disparities. Lastly, another member noted that the inadvisability of 250 NM local sharing in the densely populated mid-Atlantic region, where over 25% of the US population is concentrated, whereby over 60 transplant centers appear on many match runs was ignored in the current allocation scheme. Failure of the allocation scheme to make allocation practical for the OPO's leads to long cold ischemic times and too many organs allocated out of sequence, as late offers, open offers, and offers to any center that will accept. The continuous distribution concept, if it is to work, must be used to increase the importance of efficiency in allocation by increasing the value of short distance in a non-linear fashion, respecting the difference between driving short distance, driving extended distance, and the inefficiency and inappropriateness of using commercial aircraft for organ transportation.

Anonymous | 09/12/2022

One attendee commented that continuous distribution will not fix disparities between centers because they are linked to organ offer acceptance. They went on to comment that the focus needs to be on centers using the organs they receive. Several attendees commented that they supported the concept but based on the complexity of the system, much more in depth discussion and modeling is needed. Two attendees commented that frailty/conditioning are important variables to include. Another attendee wanted more information about how exception requests and multi-organ candidates would be included. One attendee agreed with exploring the best approach to including an attribute for a candidates social determinants of health.

Anonymous | 09/08/2022

A member supported stratification of HCC candidates and interweaving them with non-HCC patients. Several members pointed out the need to balance recipient and donor availability. A member pointed out that for coastal communities, rather than use circles and NM, we should use ratios based on the percentage between recipients and donors. Another member supported a scaling on distance modifier that should be different for each region, based on the region’s geographic structure (i.e. coastal, less populated areas, etc.). Further, the policy should take into consideration the expedited placement and back-up offer. A member pointed out that the committee should look at the population of women who are over 50 and under 65, with an alcohol diagnosis, and how they could be inadvertently negatively impacted by this policy change. A member explained that he doesn’t agree with the notion of "isolated centers" backing themselves up – it is a concept that promotes the idea that organs "belong to the center" and further disadvantages centers in high density areas. The increased availability of pre-donation imaging should further decrease the "decline in OR for size" events. Member suggested that the committee should consider the following for attributes: re-transplant status of a candidate, frailty, post-transplant survival, prior living donor, split liver willingness, HCC stratification. A member stated that the committee should not include “distance”. A member suggested that the committee include transplant professionals with pediatric expertise (i.e. whose patient care is primarily with children and adolescents, practice primarily at a children's hospital, and/or are board-certified in a pediatric specialty) in the committee’s work on continuous distribution.

Anonymous | 08/26/2022

Comments: Several attendees commented that post-transplant survival should be included in the attributes. One went on to recommend that AHP should always be called a values exercise so that the community understands that we are asking them to identify values. Another attendee recommended that a centers acceptance history should be considered in the attributes. They went on to comment that if a liver is accepted and ultimately turned down, there should be a pathway for re-allocation close to where it was initially accepted, particularly for high PRA livers and livers procured from DCD donors.

Carlos Marroquin | 08/18/2022

Patients with end organ disease develop malnutrition and metabolic consequences of deranged metabolism that is compounded by associated co-morbidities. It is also well established that malnutrition and progressive muscle wasting contribute to the deterioration of patients with end organ disease. The onset of renal and liver disease initiates a cascade of physiologic injuries that are magnified as these diseases progress. Few patients can maintain any functional level of conditioning and subsequent stressors induced by associated diseases and dense fatigue that sets in introduce a vicious cycle which makes recuperation impossible. As such, frailty evolves rapidly in patients with end organ disease. It has also been demonstrated that frailty affects perioperative outcomes, long-term outcomes, and post-operative mortality compounding the staggering cost of healthcare. To mitigate the perioperative risks and costs associated with frailty, we could develop screening tools to assist the clinical evaluation of patients referred for transplantation. As we have identified that frailty contributes to poor outcomes, our objective should be to identify transplant candidates who are frail and may benefit from pre-conditioning and nutritional repletion before transplantation. Due to the lag between evaluation and transplantation, we have an opportunity to improve a given transplant candidate’s physical and emotional reserve to help them tolerate the insults of transplant surgery and associated immunosuppression. UNOS could institute a process of evaluation for frailty and a “Transplant Conditioning Program (TCP),” which include an interventions to recover from frailty that also help maintain a state of wellness. This assessment could be coupled to each organ specific assessment and would have to capacity to improve the global outcomes and optimize each organ utilization. I would love to work with a committee that would look at this possibility as a pilot project.

Harvey Solomon | 08/11/2022

I suggest that the committee consider including in the design of concept DRI, historic acceptance of accepting transplant center and ability to backup offer in the immediate vicinity if declined.