Update on Continuous Distribution of Livers and Intestines, 2023
At 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 for various factors, such as medical urgency, candidate biology, patient access, and placement efficiency. Continuous distribution will remove the hard boundaries built into the current framework to increase equity for patients and transparency in the system.
This update contains results from the values prioritization exercise that was open to the public during the Winter 2023 public comment period. The paper will detail recent discussions and decisions regarding specific attributes, such as geographic equity and post-transplant survival. Additionally, it will provide an overview of the next steps for the continuous distribution of livers and intestines projects.
Click the link for a closer look at Continuous Distribution: https://optn.transplant.hrsa.gov/policies-bylaws/a-closer-look/continuous-distribution/
- The community is asked to provide feedback on the committee’s progress to date and the plan for moving the project forward
- The committee is seeking feedback on specific topics such as
- Including post-transplant survival in the calculation
- Amount of priority for proximity
- How to measure geographic equity
- What it's expected to do
- Provide a more equitable approach to matching candidates and donors.
- Remove hard boundaries 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 request for feedback is not a proposed policy change, but will help the Liver and Intestinal Organ Transplantation Committees develop a future policy proposal.
Terms to know
- Attribute: Criteria used to classify then sort and prioritize candidates. For example, in liver allocation, criteria include medical urgency, post-transplant survival, candidate biology, patient access, and placement efficiency.
- Analytical Hierarchy Process (AHP): An exercise to assist with decision-making that asks participants to rate the importance of an attribute when it is compared to another attribute.
- Composite Allocation Score: Combines points from multiple attributes together. This request for feedback proposes the use of composite allocation scores in a points-based framework.
- Mathematical Optimization: A system that uses machine learning and artificial intelligence to quickly and accurately predict outcomes from thousands of potential policy scenarios.
- Rating Scale: Describes how much preference is given to candidates within each attribute.
- Weights: Reflect the relative importance or priority of each attribute toward our overall goal of organ allocation. Combined with the ratings scale and each candidate’s information, this results in an overall composite score for prioritizing candidates.
OPTN Organ Procurement Organization Committee | 09/21/2023
The OPTN Organ Procurement Organization Committee thanks the OPTN Liver and Intestinal Organ Transplantation Committee for their work and for the opportunity to comment on this request for feedback.
One member recommended modeling or data analysis to understand how many centers would be qualified to receive medically complex donors.
A member noted they like the idea of using greater than or equal to 30% hepatic steatosis when categorizing “hard to place” livers and allocating them more quickly because they tend to get the liver biopsy results late. The member recommended that a new match be run once a liver biopsy has been performed to prioritize centers that accept highly medically complex livers. A member suggested that the timing for when OPOs can place their livers expeditiously be modified to allow expedited allocation once they receive a biopsy result.
A member pointed out that pre-recovery liver biopsy is not always an option, particularly because more than 40 percent of donors are DCD. The member suggested using non-invasive liver elastography to perform assessment of livers. A member shared that their program found limited correlation between non-invasive elastography and in-OR liver assessments, and therefore did not recommend using non-invasive elastography alone.
A member questioned, since the Liver Committee is looking at operational efficiencies, if there has been any more discussion surrounding the multiple acceptance proposal.
A member mentioned they think it will be interesting to see the effect of the organ offer acceptances, which is part of the OPTN Membership and Professional Standards Committee (MPSC) review as of July 2023, especially how it might push performance. They are concerned with past performance evaluation, as medical team members impacting the feedback may leave the program, which could prevent a program from getting back on track.
A member is concerned with having one candidate listed at two centers, as this could make programming more challenging.
A member noted that allocating DCDs locally has been beneficial for them. A member said it’s the expense of traveling for a potential DCD donor that might progress to become an actual donor. Therefore, having the ability to prioritize local centers that are willing to put the resources forward makes a difference in utilization, especially with the truncated timeline for DCD donors.
A member said that smaller liver transplant programs are less likely to take marginal organs compared to larger programs due to the potential impact on their program if there is a poor outcome. They worry that this will allow larger programs to continue to grow, whereas smaller centers will not have the same opportunities. The member voiced that they believe that access to transplant comes down to insurance and that uninsured candidates are disenfranchised. Insurance drives what the match run looks like and what the match run looks like drives how aggressive a center is. They continued, saying allocation out of sequence is problematic, but not as problematic as organ non-use, which should be at the forefront of the Liver Committee’s focus. They recognized that OPOs are judged by organ placement and transplant programs are judged by outcomes, which makes a huge difference.
A member raised concern about the point-system, especially since they predict the big programs getting bigger, and the small programs getting smaller. The smaller/newer programs may not have the opportunities to accept medically complex livers, thus never getting points in that category. They recommended that the Committee consider that when evaluating the number of points for that attribute, as well as how frequently centers are evaluated with that.
Hospital of the University of Pennsylvania | 09/19/2023
Healthcare costs should be considered when developing Continuous Distribution criteria.
Region 8 | 09/19/2023
This was not discussed during the meeting, but attendees were able to submit comments with their sentiment. An attendee suggested to identify a post-transplant measure and suggested to use SRTR post-transplant outcomes models as a starting point. Prior to developing continuous distribution for liver, an attendee suggested to consider lessons learned from the lung implementation and adjustments made to improve efficiency. Members said they support a better system of continuous allocation. Post transplant outcomes must be part of the consideration. This last iteration severely disadvantaged patients in rural areas, which needs to be addressed. An attendee suggested the committee focus on placement efficiency, logistical considerations and cost to the transplant centers and explained that expenses are growing exponentially in the transplant centers as a result of increased travel, increased organ offers, need to staff increases in these areas and the cost of machine perfusion, and that the burden cannot solely rely on the transplant centers to fund all of these changes.
Association of Organ Procurements Organizations | 09/19/2023
AOPO appreciates the ongoing work of the OPTN Liver and Intestinal Organ Transplantation Committee to implement continuous distribution of livers and intestines. AOPO will focus its response on the following questions posed by the Committee.
· Do you agree with the Committee’s decision to not include an attribute for post-transplant survival in the first iteration of continuous distribution?
AOPO acknowledges there is not currently an ideal model to support inclusion of the attribute post- transplant survival and strongly encourages the committee to incorporate post-transplant survival in future iterations of continuous distribution as improved models are developed in order to achieve better transparency and consistency across organ allocation systems.
· Do you have any feedback for how geographic equity should be incorporated as an attribute in
liver candidate’s composite allocation score?
AOPO is eager to see the Committee apply mathematical optimization to offer rates to develop Geographic Equity as an attribute in Continuous Distribution. AOPO agrees with the Committee on the importance of similar MELD score patients receiving similar access to offers regardless of the location of their transplant center.
· Do you have any feedback for ways to increase efficiency in the organ allocation and placement process, especially given the low priority assigned to proximity in the VPE?
AOPO applauds the Committee’s response rate of participants in the VPE inquiry, particularly patient and caregiver response rate. AOPO is again eager to see the application of mathematical optimization applied to the attribute of proximity. Any model should achieve increases in organ utilization and fewer waitlist deaths. Incorporating acceptance rates with proximity factors are important considerations in modeling an allocation system where the best patient for the organ is identified more expeditiously.
Additionally, application of acceptance rates should result in fewer late declines which are problematic in successfully re-allocating an organ and negatively impacts utilization.
· Do you agree with the purpose for each attribute assigned in Table 1?
AOPO agrees with the purposes stated for each attribute in Table 1 and encourages the committee to continue to develop added emphasis on increasing efficiency in organ placement. If OPTN Policy 5.6.C: Organ Offer Acceptance Limit is not modified to limit a transplant center to have one organ offer acceptance for each organ type for any one candidate this Committee must work to eliminate the inefficiencies and resultant organ discards.
· Do you have any feedback on outcome metrics or ways to assign points to candidates for each attribute in the optimization analysis?
AOPO believes the ultimate outcome metrics should be increased organ utilization rates and reduction in pretransplant mortality rates. AOPO looks forward to reviewing the Committee’s work regarding assignment of points for each attribute in future updates from the Committee.
OPTN Transplant Administrators Committee | 09/19/2023
The OPTN Transplant Administrators Committee thanks the OPTN Liver and Intestine Transplantation Committee for their dedication and work on this project. The Committee appreciates the difficulty of developing an equitable and broadly applicable organ allocation system with continuous distribution.
Region 9 | 09/19/2023
This was not discussed during the meeting, but attendees were able to submit comments with their sentiment. A member stated that since post-transplant survival is predictive and not a fact, it should not be included in the composite allocation score.
UC San Diego Health | 09/19/2023
The UC San Diego Health Center for Transplantation appreciates the ongoing updates provided by the Liver and Intestinal Committee regarding their progress on the development of a continuous allocation model and generally agrees with the Committee’s decisions regarding specific attributes, such as geographic equity and post-transplant survival.
• We acknowledge the community’s support for and generally agree with incorporating post-transplant survival as an attribute in any allocation system as a means to achieve the best use of donated organs. However, absent a reliable model for post-liver transplant survival, we support the Committee’s decision to exclude this attribute from the first iteration of continuous distribution.
• We agree with the Committee’s intent to broaden the scope of population density, which was initially proposed as an attribute, to geographic equity. On to the much harder question of how geographic equity should be incorporated as an attribute in liver candidate’s composite allocation score, the Committee and community must remember that the goal of continuous distribution is smarter distribution that promotes patient access, not necessarily broader distribution. While the most recent iteration of liver allocation policy attempted to balance patient access and address concerns related to increased travel and recovery costs by incorporating “proximity points,” we would be interested to further explore the Committee’s idea of analyzing independent objective measures such as offer rates and match run sequence order and from there pursuing mathematical optimization.
• Particularly given advancements in organ perfusion and preservation. we agree that candidates at similar MELD scores should receive similar access to liver offers regardless of the location of their transplant program, however this argument does not acknowledge the complex operational realities of the overall healthcare system in which transplant is a simple component. These technologies and travel, especially by air are incredibly expensive – not every program has the means or resources to support such practices. We must be mindful of the potential unintended consequences on an already fiscally strained system.
• When considering ways to increase efficiency in the organ allocation and placement process, we have been impressed with the development and roll out of the kidney organ offer filter tools. We would urge the Committee to prioritize developing and making readily available similar tools for liver offers.
• We would also support earlier use of open offers for better earlier placement of organs and consistent use of backup recipients. As the practice of NRP and pump perfusion expands, there may be more opportunities to allow allocation after recovery. Finally, we would encourage the Committee to evaluate of the specific reasons for late declines, as they may be clinically relevant and justifiable (for example, programs that may accept for a candidate based on virtual crossmatch but later must decline due to a positive prospective) to identify other potential opportunities for improvement.
Transplant Families | 09/18/2023
Transplant Families agrees with the OPTN Pediatric Transplantation Committee's comments and appreciates the OPTN Liver and Intestine Transplantation Committee's presentation. We also urge you to take into consideration:
Medical Urgency: It's critical to ensure that pediatric medical urgency scores are age-adjusted and not directly compared to adult scores. The integration of OPOM with EMR data for real-time information should be explored, and effective communication of this model to the community, especially families of pediatric candidates, is essential.
Post-Transplant Outcomes: There is a need for careful consideration in the Liver and Intestine Transplantation Committee's work when considering the current model for Kidney EPTS does not effectively discriminate between children. Regarding geographic equity, we support its inclusion but call for more data and clarification on how it will be implemented.
Status 1B Transition: Agree on incorporating Status 1B into continuous distribution and recommends that Status 1B candidates receive more points than any MELD or PELD candidate but fewer points than Status 1A candidates within the medical urgency attribute.
We thank the OPTN Liver and Intestine Transplantation Committee for this update.
Anonymous | 09/18/2023
I agree with the OPTN Pediatric Transplantation Committee comments and appreciates the OPTN Liver and Intestine Transplantation Committee's presentation. I also urge you to take into consideration:
* Medical Urgency: It’s critical to ensure that pediatric medical urgency scores are age-adjusted and not directly compared to adult scores. The integration of OPOM with EMR data for real-time information should be explored, and effective communication of this model to the community, especially families of pediatric candidates, is essential.
* Post-Transplant Outcomes: There is need for careful consideration in the Liver and Intestine Transplantation Committee's work when considering current model for Kidney EPTS does not effectively discriminate between children. Regarding geographic equity, we support its inclusion, but call for more data and clarification on how it will be implemented.
* Status 1B Transition: Agree the incorporation of Status 1B into continuous distribution and recommends that Status 1B candidates receive more points than any MELD or PELD candidate but fewer points than Status 1A candidates within the medical urgency attribute.
Region 7 | 09/18/2023
This was not discussed during the meeting, but attendees were able to submit comments with their sentiment. An attendee noted that geographic equity is now complicated by machine perfusion and the transplant community needs to decide if machine perfusion should play a part in allocation models.
American Society of Transplant Surgeons | 09/18/2023
Society for Pediatric Liver Transplantation | 09/18/2023
The Society for Pediatric Liver Transplantation (SPLIT) supports the concept of continuous distribution and its goals of objectively and efficiently prioritizing people on a liver transplant match run and reducing geographic disparities in access to liver transplant. In designing a composite allocation score for liver transplant, we strongly encourage the Committee to consider these points related to children and adolescent liver transplant candidates:
• The VPE signals strong stakeholder support for high prioritization of pediatric candidates – with the importance of being a child or adolescent ranked almost equal to the importance of being a medically urgent candidate by most participants. The Liver CAS should prioritize children to reflect this community sentiment.
• We agree that currently available metrics for estimating post-transplant survival are not adequate for accurately estimating long-term survival of children, or determining which children might live longer than other children, since the vast majority of children live for decades after the liver transplant. If post-transplant survival is included in the CAS, an initial goal might be to discourage “futile” transplants, i.e. transplants with very short estimated post-transplant survival (• For children, regional and national sharing of livers is critical for adequate access to organs – given their smaller size, with fewer appropriate donors. Such sharing is also more feasible, given the smaller number of children listed for transplant. Sharing livers more broadly, especially from pediatric donors, has helped increase pediatric transplant rates and decrease mortality – continuous distribution should still allow for national sharing of livers for pediatric candidates.
• Our ultimate goal for children is to eliminate pediatric waitlist mortality – not just to minimize their waitlist time. Per Table 1, minimizing time on the waitlist for pediatric candidates, truly prioritizing split-able livers for children, and ensuring that medical urgency for children reflects their age-adjusted expected mortality compared to adults are key steps towards achieving this goal.
• “Travel efficiency” must be calculated so that it does NOT de-prioritize children for pediatric donors or split-able livers. Broader sharing of organs for children, who are harder to size match, has been critical for increasing transplant rates and is more feasible for this smaller population.
• Pediatric candidates should still be prioritized for pediatric donors.
• If OPOM is used instead of PELD/MELD for determining medical urgency in the CAS:
o A pediatric OPOM score derived from pediatric data is essential for priority ranking pediatric candidates
o Improvements to medical urgency ranking for children that have recently been approved and implemented must be integrated into this new system. These include:
• Calibrating pediatric medical urgency scores to adult scores such that estimated pediatric waitlist mortality is based on age-adjusted values.
• Recognizing that lab data does not accurately estimate waitlist mortality risk for a significant proportion of pediatric candidates – because of the heterogenous disease pool, the relatively small number of children waitlisted, and the high use of exception PELD/MELD scores
• Consideration of whether adult or pediatric priority scores are most appropriate for adolescent candidates – based on adolescent data
• Equal priority for male and female adolescents
• Prioritizing children for “split-able” livers would increase efficiency and the number of transplants.
We also recognize that understanding how previous changes have impacted allocation and transplant, and integrating those learnings into continuous distribution, is critical to success of the new system. As we work towards continuous distribution, continuing to evaluate how recently implemented policies have impacted children, and other vulnerable populations, so that the CAS truly offers an improvement over current allocation will be important.
OPTN Ad Hoc Disease Transmission Advisory Committee | 09/15/2023
The Ad Hoc Disease Transmission Advisory Committee (DTAC) appreciates the opportunity to provide feedback on this concept paper and supports the OPTN Liver and Intestinal Organ Transplantation Committee’s efforts to move toward continuous distribution. DTAC members identified that continuous distribution changes could impact travel patterns for organ distribution and it is important to consider that transplant centers in certain parts of the country may be less familiar with diseases endemic to other parts of the country. The committee should consider this in developing its continuous distribution policy proposal, and also consider education or guidance on screening of donors to minimize communication issues about test results for areas with differences in endemic testing.
Gift of Life Michigan | 09/15/2023
We appreciate the Liver and Intestinal Organ Committee's work to move to Continuous Distribution, and to develop Composite Allocation Scores (CAS) and other means by which to objectively score waiting patients. We also appreciate the Committee's comprehensive consideration of multiple variables related to CAS formulation, and the weighty discussions around outcomes.
We believe the Committee's conclusion that a reliable tool to predict outcomes does not quite yet exist, and support their intent to exclude that variable until such time a tool becomes available. There is a delicate balance between the life of the waiting patient and computer modeling that predicts success or failure of a transplant, and caution its inclusion unless modeling is highly reliable.
Region 6 | 09/15/2023
This was not discussed during the meeting, but attendees were able to submit comments with their sentiment. One attendee questioned the impact of continuous distribution on utilization and cost. Another attendee commented that there needs to be modeling for regions in the corners of the country. They added that region 6 borders the ocean and Canada and has a smaller population per capita and that given regional differences, continuous distribution cannot be one-size-fits-all. One attendee commented that pediatric candidates should not be disadvantaged.
OPTN Ethics Committee | 09/15/2023
The OPTN Ethics Committee thanks the OPTN Liver & Intestinal Organ Transplantation Committee for their work on this update and for the opportunity to provide input. The Committee offers the following comments.
While we understood the intent, the Committee wonders if injecting a principle of “geographic equity” aimed at providing equal access to transplant regardless of geographic location of transplant program in addition to placement efficiency risks placing an inappropriate emphasis on geography, which ultimately may undermine equity. Overemphasis on geography risks undermining the patient-centered focus of the model, which should be aimed at achieving a reduction in “inherent differences” (which we note are not static and change over time). Relying on other, patient-specific attributes (e.g., medical urgency and proximity efficiency) may better accomplish this. Emphasizing geography also arguably creates inconsistency among CD allocation policies and shifts the focus away from the individual patient in deference to bounded regions, which has already been found in prior analyses to be inappropriate.
The policy recommendation should ultimately ensure that proximity and travel efficiency considerations do not outweigh equity and are incorporated to the extent they are required to maximize net benefit (e.g., prevent organ waste and ensure an efficiently managed system) and equity. Weighting both travel efficiency and proximity efficiency, and then also including a separate attribute for “geographic equity” in the CAS, may actually result in over-prioritizing utility and undermining equity. It should be noted that travel efficiency may conflict with medically complex organ placement in circumstances where more aggressive transplant centers with access to ex vivo perfusion devices may require longer transportation.
The Liver and Intestine Committee should be commended for its robust VPE process with unprecedented patient participation but should carefully assess any potential bias in the results of the VPE based on 80% of responses coming from transplant centers and patients.
Feedback on the medical urgency attribute included support of modeling use of OPOM vs MELD and PELD. This contributes to transparency and perception of fairness, especially when considering patients/caregivers. Patients that have been on the waiting list for a longer length of time with a low MELD score should have priority. Many of these patients are much sicker than their MELD score.
With regard to the post-transplant survival attribute, we recommend that the Liver & Intestinal Committee should consider modeling reliance on MELD/PELD vs. a post-transplant survival attribute to ensure that the carryover does not unintentionally “smuggle in” biases from the existing system that would affect equity and utility.
Finally, a Committee member noted that it makes sense to consider challenges for patients with alcoholic fatty liver disease having high INR (international normalized ratio) compared to other liver candidates, and to consider potential disparities for women having lower muscle mass and a lower transplant rate compared to men.
American Society of Transplantation | 09/15/2023
The American Society of Transplantation (AST) is generally supportive of what is outlined in the committee update, “Update on Continuous Distribution of Livers and Intestines,” and offers the following comments for consideration:
• The proposed continuous distribution system incorporates both removal of hard geographic limits from prioritization and simultaneous implementation of a major overhaul in the prioritization scheme for patients to include several prioritization metrics that have not been validated with regards to alterations in waitlist and post-transplant outcomes. The impact of these factors should be carefully modeled and should not just be implemented and reassessed in real-time. While the system has potential to improve allocation, there is a real risk of unforeseen adverse impact on certain patient populations.
• Concern was raised regarding the difficulty of reallocation of organs, such as in the OR, with this system. Some inherent flexibility should be maintained for intraoperative reallocation so as not to inadvertently decrease utilization of transplantable organs.
• There are concerns about the continuous distribution implementation timeline. Liver allocation has only recently moved towards MELD 3.0, and several in the community were reluctant to see additional changes implemented in the absence of data regarding the effect of these most recent allocation changes, including extensive modeling of a new proposed system. There is precedence for continuous distribution, with the UK currently implementing a Net Benefit model for organ allocation; however, this system did not result in improvements in post-transplant outcomes when applied to external populations in New Zealand.
• It is stated that the committee will not include post-transplant outcomes in the initial iteration of continuous distribution. While avoidance of liver transplant futility is one of the principles defined in the Final Rule, current pre-transplant indices have not been shown to reliably identify patients at high risk for post-transplant mortality. The current population of liver transplant recipients is evolving, and historic indices may not reflect risks of the current population. Nonetheless, calculated risk for post-transplant mortality is continuously assessed by the SRTR in evaluation of center-level transplant outcomes. The Committee should explain why these models cannot serve as a starting point for a post-transplant score component.
• Although frailty metrics have been proposed as a mechanism to predict post-transplant outcome, current metrics are subject to reporter bias and manipulation. The AST recommends collecting data to assess the impact of frailty on both pre- and post-transplant mortality so that validated frailty factors can be incorporated in these models. Similar consideration should also be given to particularly vulnerable populations, such as pediatrics, re-transplant, ACLF, ALF, and geographically and socioeconomically disadvantaged groups.
• There is a need to address utilization of DCD organs and implementation of machine perfusion technology in the design of any algorithm, as these have the potential to affect center practice and future organ utilization. Especially in the case of machine perfusion technology, existing data is too preliminary to determine long-term implications.
• The proposed algorithm denotes a major alteration in liver and intestinal organ allocation. OPTN data regarding the prioritization of continuous distribution demonstrates differing opinion of the various stakeholders regarding the importance of distribution components. In contrast, medical urgency (as measured by MELD and its derivatives) is identified by the final rule as one of the main dictates for waitlist prioritization, and it must continue to be weighted as such.
• Clarification is necessary regarding how the risk for increased waitlist mortality for patients with MELD exceptions will be accommodated so as to not disadvantage these patients.
• The local impact on candidates residing in/near poorly performing OPOs should be considered, and OPO performance standards should be created and adhered to.
• While incorporation of body surface area may improve inequity for short stature patients, concerns were raised that these metrics may be artificially altered through modulation of volume status.
• Prioritization should be considered for patients able to receive organs via ground transportation, given its ability to make transplant more accessible and reduce transportation costs.
• The AST agrees with the committee’s decision to table discussions on MELD/PELD and OPOM/POPOM until they can assess the results of each medical urgency score in the mathematical optimization analysis.
• It is unclear how incorporating a “population density” or “geographic equity” score component will improve patient-centered equity goals of continuous distribution. It is critical that the new liver allocation system solely focus on candidate access, not transplant hospital access.
• While proximity was not a prominent attribute in the values prioritization exercise (VPE), it may play a relevant role in the acceptance and utilization of potential donor livers. Proximity may not need to be heavily weighted for the continuous distribution model but for efficiency in allocation or placement, two options include:
o Facilitated placement with centers known to aggressively accept open
offer/intraoperative offers at a certain rate if the liver has not been placed
by some time period prior to organ recovery.
o Designation of a primary local backup as the first choice backup if there is
an intraoperative refusal.
• Regarding attributes in Table 1, all attributes are independently discussed in the proposal and/or a part of the VPE except for travel efficiency. Given that there will be emphasis on geographic equity and proximity efficiency, we wonder whether travel efficiency has to be included in the model to further improve utility, access, or equity.
• Particularly given advancements in organ perfusion and preservation, we agree that candidates at similar MELD scores should receive similar access to liver offers regardless of the location of their transplant program, however this argument does not acknowledge the complex operational realities of the overall healthcare system in which transplant is a simple component. These technologies and travel, especially by air are incredibly expensive – not every program has the means or resources to support such practices. We must be mindful of the potential unintended consequences on an already fiscally strained system.
• The implementation of kidney organ offer filter tools has been helpful and the AST would urge the OPTN to prioritize developing similar tools for liver
American Society for Histocompatibility and Immunogenetics | 09/14/2023
The American Society for Histocompatibility (ASHI) and its National Clinical Affairs Committee (NCAC) appreciate the opportunity to provide feedback around the criteria or attributes that will be used for continuous distribution. ASHI supports applying the most weight for medical urgency and candidate biology.
OPTN Pediatric Transplantation Committee Meeting | 09/13/2023
The OPTN Pediatric Transplantation Committee thanks the OPTN Liver and Intestine Transplantation Committee for their presentation and for the chance to provide input on the development of continuous distribution. The Committee offers the following feedback regarding medical urgency, post-transplant survival, geographic equity, and the transition of Status 1B to continuous distribution.
First, the Committee asks the Liver and Intestine Transplantation Committee to keep in mind the specific considerations for pediatric candidates in the medical urgency attribute. While it is promising to see that the Committee is taking into account the pediatric version of OPOM (POPOM), it is important to consider the cohort size for pediatric candidates when making the updates to the model as well as considering how the new pediatric medical urgency scores will need to interdigitate with the adult scores. Integration of principles already incorporated into PELD-Cr is critical – most importantly adjusting pediatric medical urgency scores so that their estimated waitlist mortality is age-adjusted and not directly compared to estimated mortality of all adults on the waitlist. Whether adolescents will be listed using the pediatric or adult medical urgency score should be evaluated using retrospective data from this age group. One area to consider for future development is how the OPOM model could integrate with EMR data to provide more real-time information to use in allocation algorithms. The Liver and Intestine Transplantation Committee should think about how information about this model and how it will be used in allocation will be communicated to the community, especially for families of pediatric candidates.
Second, the Committee asks that throughout Liver and Intestine Transplantation Committee work on estimated post-transplant outcomes attribute, challenges associated with estimating post-transplant outcomes in children are considered at each step. Members noted that for Kidney EPTS, the model was not found to effectively discriminate between children, so all children are given the “best” EPTS score. Regarding geographic equity, members were supportive of the inclusion of this attribute, but more data and information about how it will play out are needed.
Third, the Committee held discussion on how to best incorporate Status 1B into continuous distribution and appreciates the opportunity to weigh in. Overall, the Committee recommends that within the medical urgency attribute Status 1B candidates get more points than any MELD or PELD candidate but fewer points than Status 1A candidates. Within the 1B category, the Committee recommends that urgency continues to reflect the rankings recently agreed upon by a joint workgroup and approved for policy implementation – decompensated chronic liver disease, then liver tumor, then metabolic disease patients. It may be acceptable, in rare instances, for a highly urgent MELD or PELD candidate to be ranked higher than a Status 1B candidate on a match run due to the impact of other attributes in combination with the medical urgency attribute on the overall composite allocation score. The Committee suggests robust modeling to explore how this would work across many scenarios.
Region 11 | 09/12/2023
A member commented that they support all allocation efforts that improve the efficiency and efficacy of utilization for donated livers and intestines; this consideration should be assessed for all potential allocation changes.
sara clark | 08/30/2023
You are shutting out the pediatric voice with this proposal.
Region 4 | 08/30/2023
This was not discussed during the meeting, but attendees were able to submit comments with their sentiment. One attendee commented that the community needs to better understand the impact of acuity circles and broader allocation before moving to continuous distribution.
OPTN Transplant Coordinators Committee | 08/28/2023
The OPTN Transplant Coordinators Committee thanks the OPTN Liver and Intestinal Organ Transplantation Committee for their work and for the opportunity to comment on this proposal.
A member asked if there was any consideration on how machine perfusion will impact geographic equity, and if not, recommended it be considered in how it will affect the continuous distribution system. Regarding post-transplant survival, a member said they strongly agreed with the Liver and Intestinal Transplantation Committee’s position, as there is no supported model to help predict this outcome. The member asked why liver and intestine transplants were prioritized over all multi-organ transplants. The Vice Chair of the Liver and Intestinal Organ Transplantation Committee said that there are few liver and intestine candidates on the waitlist, but we must give them priority compared to liver alone candidates because they have limited options in organs they can receive.
Anonymous | 08/11/2023