Comments

OPTN Organ Procurement Organization Committee | 09/25/2024

The OPTN Organ Procurement Organization (OPO) Committee thanks the OPTN Liver Transplantation Committee for their efforts on the Liver Continuous Distribution proposal.

Members expressed interest in identifying patients or centers willing to travel farther or use different devices, such as NRP (Normothermic Regional Perfusion). One member shared that some centers are hiring surgeons specifically for organ recovery. There is a debate about the responsibility of transplant surgeons in donor operations. Members discussed allocation concerns, with worries that proximity points might give an advantage to less sick patients over sicker ones. Acuity (how ill a patient is) is considered the most important factor in allocation. The allocation system aims to balance multiple factors (15 categories were mentioned). Members advised that there are challenges in performing split liver transplants due to the geographical spread of allocation. They mentioned that losing relationships between centers has affected the ability to perform the split. Discussions were had about potentially removing the penalty for split liver transplants in outcome reporting.

Region 5 | 09/25/2024

• Region 5 supported the liver continuous distribution model and concepts, with a lot of feedback on geographic factors, travel logistics, and pediatric liver candidates. The region felt it was important for the committee to spend time looking into travel logistics when developing the liver continuous distribution model. They also confirmed that travel distance does affect allocation. Several attendees commented that their organization opts to fly a liver when it is more than a 2-3 hour drive away or is out of state. Another member pointed out that driving distance will vary depending upon the rural versus suburban area and the season. The member suggested that it would be helpful to evaluate current data and the distance between transplant center and donor center. An attendee pointed out that geographic equity needs to be highlighted for states with greater rural populations (for example, Idaho and Montana). Regarding exceptions, an attendee said that certain organs might not be suitable to ship long distances, and the committee should keep this in mind in an additional effort to reduce organ non-use.

• There was a lot of support for the committee to focus on pediatric liver candidates. They believed it was important to retain pediatric priority for pediatric donors and suggested to create a process to identify quality livers that can be split. A pediatric liver team pointed out that if children are not eligible for additional priority related to their BSA, it will be essential to consider how BSA-related prioritization will compare to pediatric prioritization to ensure that children are not under-prioritized compared to small adults. They agreed with the concept of a donor modifier and suggested that BSA priority be used for small donors. But if applied in pediatric match runs, there needs to be a system in place to ensure children are highly prioritized for pediatric organs. They agreed with the inclusion of priority for initiating a split transplant, but strongly encouraged the committee to consider a more meaningful variable than "willingness to accept a split liver". The committee should pay attention to how this variable is actually defined. They also agreed with continued use of PELD to determine medical urgency for now; and said if moving to OPOM, it will be essential to further develop the pediatric version. In simulation phase, it will be important to track transplant of pediatric donors into pediatric recipients. An attendee inquired whether there would be a different score for pediatric candidates.

• A member suggested that donors in remote areas, and donors with forced late reallocation should probably be considered complex unless NMP is being used. There was a suggestion for the committee to consider whether there will be significant changes in the near future on the degree to which an older or DCD liver is really a “high risk” liver considering NRP and machine perfusion is available. An attendee said that large livers and livers with steatosis are challenging to allocate. These characteristics are generally known at the time of organ offer. Those variables should be included in the definition of medically complex livers. In order to allocate small livers to recipients that need them, recipients with a small capacity need to be identified, and this is not reliably identified by BSA, BMI, height or weight. Frequently the candidate's CT scan must be used to make the determination on the appropriate liver size. They inquired if it was possible for centers to designate waitlist candidates who need an exceptionally small liver.

• A member suggested that the committee confirm that MELD 3.0 addressed sex disparity.

• A member provided a general comment that is applicable to all organs in continuous distribution. They asked that the committee keep in mind directly and indirectly related increased costs associated with continuous distribution implementations.

Gift of Life Michigan | 09/24/2024

We appreciate the Committee’s work on this initiative and encourage its continuation.

We do not believe there are reasonable and consistent guidelines or framework that can be built around travel (e.g., driving versus flying) because of the variation in distances, programs, weather, etc.), but we do acknowledge that they are important considerations.

The exceptions described by the Committee seem reasonable and justified.
We believe the Committee is addressing this at a pivotal point in transplant evolution because of the growing use of Normorthermic Regional Perfusion (NRP) and Normothermic Machine Preservation (NMP). Discussion about Donation after Circulatory Death (DCD) must somehow now include these practices despite variation in whether the OPO or the transplant center engages in one or both; the impact of these platforms on organ function, including the definitions of ischemic time; consistency of important points in the progression of a DCD case; and many other factors. We believe the use of these approaches will expand rapidly, and that the Committee (and the OPTN) will benefit from figuring out how to allow for their use.

OPTN Heart Transplantation Committee | 09/24/2024

The OPTN Heart Transplantation Committee thanks the OPTN Liver & Intestine Transplantation (Liver) Committee for requesting feedback about the Continuous Distribution of Livers and Intestines Update, Summer 2024 during the Committee’s September 17, 2024 meeting. The Committee members appreciated the presentation, as the information was helpful in their development of a continuous distribution of hearts allocation framework. The members especially appreciated the presentation’s focus on incorporating exception requests in continuous distribution because the Heart Committee has recently started similar discussions about exceptions. The Committee was interested in the Liver Committee’s efforts to transition their existing standard exceptions into the continuous distribution framework. Similar considerations await the Heart Committee as they make decisions about transforming existing statuses and exception requests into the heart continuous distribution allocation framework. A Committee member asked whether the Liver Committee has experienced issues with very high numbers of submitted exception requests that may not include enough clinical information to justify a higher status. Committee members were pleased to learn about the benefits associated with the Liver Committee’s implementation within the last decade of a national review board for considering exception requests and how that appears to have improved the exception request process. Another member expressed support for the Liver Committee’s inclusion of an attribute for geographic equity within the patient access goal. Several Committee members noted the complexity associated with the Liver Committee’s proposed means of incorporating exceptions in continuous distribution and speculated that it may be difficult for patients, their families, and donor families to understand how the process works.

Region 3 | 09/24/2024

During the meeting, in-person attendees participated in group discussions. The liver and intestine group commented that determining when teams drive verses fly for organ recovery is complex and depends on many factors including donor management and availability of surgeons to recover onsite. Regarding the Utilization Efficiency attribute, the group commented that it should include split livers for adults and pediatric candidates and standardized DCD donor definitions. They added that those willing to accept splits should be awarded more points as it would benefit both adult and peds candidates. The group also provided feedback on how to incorporate exceptions into the continuous distribution framework commenting that candidates who are less stable should be prioritized and pediatric domino donors should receive additional points. 

NATCO | 09/23/2024

Continuous Distribution of Livers and Intestines Update, Summer 2024

NATCO appreciates the opportunity to comment on the Liver and Intestines Committee’s Continuous Distribution of Liver and Intestines Update. NATCO offers the following feedback for consideration:

• Please provide any feedback on the Committee’s decision to utilize MELD and PELD as the medical urgency score model within the first version of continuous distribution.

We agree that although there are some limitations, MELD/PELD, Status 1A, and Status 1B urgency score assignments are appropriate for the first version of continuous distribution. Further exploring Optimized Prediction of Mortality/OPOM is encouraged, however, introducing that during the first version of continuous distribution is not ideal. We would request that validation of the Pediatric OPOM model when compared to PELD and that there are no unexpected disadvantages to its use in this patient population.

• Please provide any feedback specific to the pediatric population within liver continuous distribution.

NATCO also agrees that there should continue to be prioritization placed on pediatric grafts being allocated to pediatric recipients. In addition, there needs to be more focus on splitting appropriate livers which in-turn generates more graft options for pediatric patients. When reviewing exceptions for adults, please also consider reviewing exception practices and policies for pediatrics as the majority of pediatric patients receive offers based on exception points rather than their PELD score.

• Please provide feedback on when your organization begins to fly rather than drive for organ procurement as well as any feedback on travel practices.

When reviewing travel efficiency as an attribute, NATCO’s stance is that travel practices vary from center to center and from one region of the country to another. Geography, weather, urban/rural destinations, and even traffic can impact a team’s decision to fly vs. drive. Medical urgency of the transplant candidate could also impact a center’s transportation choice.

In addition, the ability, and availability, of machine perfusion and/or normothermic regional perfusion must also be taken into consideration as those technologies can now allow for longer travel distances. Not all centers, however, have ready access to machine perfusion, for example due to cost; whereas some centers machine perfuse frequently. This variation in access could cause further disparities.

• Please provide feedback on the Utilization Efficiency attribute including input on the options for how to award candidates points and the definition of a medically complex liver offer.

The proposed definition of a medically complex liver donor that includes DCD and over 70 years of age may warrant re-evaluation as machine perfusion becomes more available. The use of DCD donors, in particular, will likely be much greater as more centers embrace, and have available to them, this technology. As stated previously, however, there is variability in accessibility of machine perfusion from center to center, therefore aggravating potential inequity amongst transplant centers.

Regarding awarding points to candidates who are willing to accept a medically complex liver, while this has a nice appeal to it, once concern we have is if the candidate(s) will truly understand what this means to them and their potential outcome.

Hospital of the University of Pennsylvania | 09/23/2024

1. Agree to use MELD/PELD for medical urgency as the other 2 options are too complex to incorporate at this time and do not offer significant advantage.

2. Consideration of DCD in utilization efficiency is problematic as most of these are good organs. The problem here is that a. not all programs have access to perfusion b. many OPOs are not going after all of the DCD and OPOs have different policies and procedures for using perfusion c. UNOS data is wholly inadequate to understand the use of perfusion technology d. the use of DCD is rapidly changing so any decision the committee makes now on whatever marginal data is available will be out of date in a year. So basically the committee is making decisions on DCD in the dark.

3. Population density needs to take into account the number of transplant programs supporting the population. There tends to be a greater number of programs per population size on the east coast compared to the west coast.

4. Continuous distribution is a great idea, however a bigger problem that UNOS continually fails to address is the variation in performance among OPOs and violations to allocation policy that are occurring with out of sequence allocation (for example XXXX). You can spend many years and millions of dollars on developing continuous distribution but it does not address the major underlying problem of OPO performance and behavior.

Region 11 | 09/23/2024

Regarding a question about when a center begins to fly, rather than drive, for organ procurement a virtual attendee noted that most kidneys are driven to their center due to limited direct flights at their airport, while surgeons fly to procure hearts. The in-person attendee group highlighted that practices for flying versus driving differ among centers, with some using a 2-3 hour driving time threshold. However, other factors like weather conditions and the use of machine perfusion also influence the decision. Regarding medically complex liver offers, the in-person attendees suggested that DCD and age 70 were considered minimum criteria, and proposed awarding points to candidates willing to accept such offers, emphasizing the need for thorough patient education. The attendee also acknowledged the complexity of exception discussions and stressed the importance of prioritizing multi-organ transplant candidates.

OPTN Transplant Coordinators Committee | 09/23/2024

The OPTN Transplant Coordinators Committee thanks the OPTN Liver and Intestine Transplantation Committee for this update on their continuous distribution work. The Committee recognizes the difficulty in developing an equitable allocation and distribution system. The Committee cautions against unintentionally creating disadvantages by awarding points to patients who are listed at centers which have historically accepted complex offers. 

Society of Pediatric Liver Transplantation (SPLIT) | 09/22/2024

The Society of Pediatric Liver Transplant (SPLIT) appreciates the opportunity to provide feedback on the Continuous Distribution of Livers & Intestines Update from the OPTN Liver and Intestinal Organ Transplantation Committee. We commend the Committee for its attention to pediatric priorities throughout the document and for sharing our goal of reducing waitlist times for children, ultimately aiming to eliminate the pediatric waitlist.

Regarding the updates on attributes related to pediatric liver transplants in the context of continuous distribution, we offer the following comments:

Body Surface Area (BSA):

It remains unclear if the Committee intends to provide pediatric candidates with additional priority based on low BSA, or how pediatric candidates will be incorporated into this proposed schema. Ideally, children should receive specific consideration within the BSA framework, with appropriate additional priority given to their typically smaller size. If children are not granted additional priority based on BSA, it will be essential to assess how BSA-related priority aligns with pediatric priority to prevent unintentional deprioritization of children relative to smaller adults. This is especially crucial for adolescents aged 12 to 18 years. While we support the concept of a donor modifier, we suggest that BSA priority be applied primarily to small donors. However, when matching pediatric donor organs, care must be taken to ensure that pediatric recipients remain appropriately prioritized for pediatric organs.

Split Liver Transplants:

We support the inclusion of priority for initiating a split liver transplant but strongly recommend that the Committee consider a more meaningful criterion than mere "willingness to accept a split liver." Currently, this option can be selected for any candidate by any transplant center, but in adult candidates, it rarely reflects actual initiation of a split liver transplant (see data here: https://pubmed.ncbi.nlm.nih.gov/29684000/). As it stands, this criterion is not meaningful and should not be used to grant extra priority. Defining this variable more rigorously will be essential to giving it weight, and tracking its correlation with actual initiation and/or acceptance of split liver transplants in the future will be critical.

Medical Urgency:

We agree with the continued use of MELD/PELD scores to determine medical urgency at present. However, should the system move towards OPOM in the future, it is imperative that the pediatric version is fully developed and thoroughly evaluated, as it has not been studied as extensively as its adult counterpart.

During the simulation phase, it will be important to track the transplantation of pediatric donor organs into pediatric recipients. Recent significant policy shifts were made to improve this metric, and as we consider further changes, it is crucial to ensure that this progress is not reversed. Children must continue to receive appropriate priority for donors aged 18 and younger. In conclusion, we appreciate the Committee's ongoing consideration of the pediatric population in these proposed changes. Our shared goal is to ensure that pediatric patients remain a priority, with the aim of reducing waitlist morbidity and mortality.

American Society for Histocompatibility and Immunogenetics (ASHI) | 09/20/2024

The American Society for Histocompatibility and Immunogenetics (ASHI) and its National Clinical Affairs Committee (NCAC) appreciate the opportunity to provide feedback on this update. ASHI continues to be supportive of prioritizing the attributes of candidate biology for transplant access. Intestine allograft survival is limited and our understanding of HLA mismatch and antibody mediated injury phenotypes is understudied. We advocate for database infrastructure to collect recipient/ donor HLA high resolution typing, CPRA, and pre-transplant DSA data to examine impact on intestine transplant outcomes.

Lance Stein | 09/20/2024

Thank you for this work. It will be extremely challenging to create models in the current era where the access to organs and the outcomes/utilization of donor organs is changing rapidly and in real time with NRP and NMP utilization. The donor pool is greatly expanding in real time. We have no standardization for these new "medically complex donors" in 2024 and beyond. Most are not "medically complex" other than they are labelled as such. I fear that any scales/weights applied to current and recent allocation behaviors will be immediately outdated and if we are using scales based on outdated data, this will be to the harm of programs and patients. Rather if one is to incorporate time/distance/travel/DRI into the weighting, we need to have a better understanding of the evolving datasets before making assumptions and changes. Also, the current issues of travel/distance may be moot with the appropriate and widespread utilization of NRP/NMP .
One solution to this conundrum would be to re-weigh the scales based on practice changes in real time on a quarterly or semi-annual basis. this should be considered.
Another challenge is how to collect historical data to create scales when practice is constantly evolving. These changes are happening quickly. some examples: 1. diseases being transplanted are evolving, ie Alcohol and MASH 2. older age recipients. 3. older and more DCD donors than ever. 4. higher risk malignancies are being transplanted. 5. evolution of recipient medical management while on waitlist. 6. Lower MELD transplants via pump technologies. These changes have been a blessing for our recipients. However all this could become moot if proposed weighting doesn't accurately capture these new and evolving practices.

Region 10 | 09/20/2024

The discussion covered several key topics related to liver and intestine allocation priorities and efficiencies, particularly for post-transplant survival, travel, and donor categorization. Post-transplant survival is currently given a lower priority in the allocation system, and it was noted that the liver allocation process lacks a reliable metric to predict post-transplant survival. The group also discussed travel efficiency, weighing the benefits of flying versus driving for organ transport. This is an evolving area due to technological advancements, but there was a consensus that broad guidelines based on cost and efficiency should be established. Utilization efficiency was another focus area, particularly the idea of incorporating a center-based aspect into the allocation score. However, participants struggled with the ethical implications of this approach. Placement efficiency, especially concerning late turndowns of organs, was highlighted as a persistent issue. It was suggested that policy changes could help address these inefficiencies. There was also discussion about how to handle exceptions in the allocation system and the need for more modeling to develop fair and effective scoring mechanisms. DCD donors were debated as a "special category." While the relevance of DCD donors to placement efficiency is recognized—given rapidly changing technology and the unique challenges they pose—it was argued that their categorization should remain distinct in the continuous distribution model. Regarding travel logistics, most organ transport now involves air travel due to changes in allocation policy. Liver transportation also predominantly relies on air travel because of greater distances involved. The issue of late declines for liver transplants continues to be a problem for OPOs. This is sometimes linked to local recovery processes where the initially accepting center bears no cost because it does not send a plane, potentially contributing to inefficiency in placement. Overall, the discussions highlighted the need for continued improvements in the allocation process, with an emphasis on addressing efficiency and fairness while considering evolving medical and logistical factors.

OPTN Pediatric Transplantation Committee | 09/20/2024

The Pediatric Transplantation Committee appreciates the opportunity to provide feedback on the Continuous Distribution of Livers & Intestines Update. While Body Surface Area (BSA) should be incorporated, there are concerns that increased allocation priority for women would decrease access for teenage pediatric candidates. It will be important to balance allocation priority needs via mathematical optimization, so that pediatric patients do not become disadvantaged.  

Additionally, Pediatric Committee members recommend that the Liver & Intestinal Organ Transplantation Committee consider how split livers may be incorporated into the allocation system. Splitting livers creates the opportunity for more candidates to be transplanted. 

Association of Organ Procurement Organizations | 09/20/2024

As we have previously stated, based on current data, AOPO generally supports the OPTN’s proposed policies related to the continuous distribution of organs. Below are our comments on the specific requests for feedback related to the Summer 2024 Continuous Distribution of Livers and Intestines Update.

The identified attributes as well as their drafted purposes and initial rating scales.

The current identified attributes address the broad spectrum of considerations critical to modeling a continuous distribution allocation system for livers and intestines and incorporate both donor and candidate attributes. AOPO supports the critical work underway and the goals associated with increasing the utilization of organs procured and, as importantly, decreasing the non-use of procured organs. Trust and transparency in the allocation system are essential, and these proposed attributes and rating scales promote those goals, as well as increase both equity and efficiency.

The Committee’s decision to utilize MELD and PELD as the medical urgency score model within the first version of continuous distribution.

The Committee’s decision to continue to utilize MELD and PELD after an extensive exploration of the benefits and drawbacks of other models is well supported. In particular, it is important to maintain a modeling system that is familiar to all involved during a new allocation process. Changing this aspect of the system would present difficulties in assessing the effects of the new process and policies and could lead to unintended and poorly understood consequences.

When organizations begin to fly rather than drive for organ procurement as well as any feedback on travel practices.

AOPO supports the proposed metrics of success and initial rating scale related to travel efficiency. OPOs partner with transplant centers to minimize cold ischemic time, increase organ utilization, and decrease organ non-utilization, and travel logistics perennially present significant challenges. Enhancing efficiencies in travel and transport practices is critical to addressing these challenges. AOPO recommends continuing to evaluate the impact of current and emerging perfusion modalities that decrease the impact of cold ischemic times. Increased use and effectiveness of such technologies would likely require changes to the initial rating scale because the geographical distance between the candidate and donor hospital and the mode of transportation becomes less important for outcomes.

BSA attribute including decision to use BSA, options for rating scales, and donor modifiers.

Including the BSA attribute enhances equity in the current system and is important. As explained in the update, the current system results in less access for small-statured candidates, who are more likely to face waitlist mortality. Adding donor modifier for the new size-based rating scale also makes sense as it will identify livers that may be more appropriately sized for small-statured candidates and give those candidates additional points. This two-pronged approach is a reasonable way to promote more equitable access to liver transplants for small-statured candidates.

The Utilization Efficiency attribute, including input on the options for how to award candidates points and the definition of a medically complex liver offer.

Including this attribute is critical, as the allocation of difficult-to-place organs can result in many challenges and inefficiencies. For organ procurement programs, significant time can be needed to place medically complex livers. This can also result in delayed organ procurement recovery times, travel logistic challenges, increased cold ischemic times for organs recovered, and the need for intra-operative or post-recovery reallocation of these medically complex livers. The Committee is considering critical options to increase organ acceptance and ultimate transplantation within the composite allocation score. The ultimate awarding of points should factor in both a candidate’s willingness to accept a medically complex liver and a transplant program’s acceptance rates for these livers. AOPO agrees that the weight of this attribute should be kept low while fully studying the risks and concerns associated with these potential modifications.

How to incorporate exceptions into the continuous distribution framework, including HCC stratification, and whether any specific donor modifiers are necessary.

The continuous distribution framework allows for benefits and new solutions by decoupling the stratification for HCC candidates from the MELD/PELD score. It also seeks to balance access, medical urgency, and desirable outcomes. The Committee’s proposal to incorporate the current nine standard exceptions into the composite allocation score is a good one, as is the proposal to adopt alternative terminology that better reflects and defines the new way the “standard exceptions” will be calculated.

Other aspects of this project, including any additional considerations that are not addressed in this paper which warrant Committee discussion.

AOPO encourages the Committee to continue to evaluate the role/impact of current and emerging technologies in assessing continuous distribution allocation models for all organs, including livers and intestines. This is especially true with emerging perfusion technologies that decrease the relative importance of distance and cold ischemic time in allocation decision.

Region 7 | 09/17/2024

A virtual attendee commented their center begins to fly rather than drive for an organ if the drive time is greater than two hours, while another virtual attendee commented their threshold is greater than 90 minutes. In relation to proximity efficiency, attendees noted changing practices influenced by technologies. One attendee suggested that the Committee should consider utilization of expensive modes of transport. In relation to utilization efficiency, the attendee noted changing practices around DCD donors.

American Society of Transplant Surgeons | 09/16/2024

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Garrett Roll | 09/16/2024

Off to a good start in this challenging task. Thank you for your work. My feedback is about the definition of medically complex livers. Currently, you have included 1) DCD donors, and 2) age over 70. DCD donors with advanced preservation are no longer medically complex, but they do consume immense amounts of transplant center resources. DCD should be removed from the list unless advanced perfusion is not used. The definition of medically complex in the current era needs to include large livers (as described by pre donation US or CT scan), and steatotic livers, and livers that are in remote locations (Alaska, Hawaii, etc) for which advanced perfusion is not indicated and cannot be employed due to expense/resource constraints (DBD donors).

OPTN Living Donor Committee | 09/13/2024

The Living Donor Committee thanks the OPTN Liver & Intestinal Organ Transplantation Committee for their efforts developing this concept paper. The Committee strongly supports prioritizations for all prior living donors into liver and intestine allocation policy as it acknowledges the altruism of living donors, demonstrates the value of reciprocity, and recognizing the need to support living donors. The Committee appreciates the OPTN Liver and Intestine Transplantation Committee’s support of living donors as valued members of the transplant community, and although this prioritization status would apply to only a very small number of individuals, it would have a high impact within the living donor and transplant communities. The Living Donor Committee offers the following as key points to consider for inclusion of prior living donor priority into continuous distribution:

·      Prior living donors should receive priority if they are listed for transplant

·      All prior living donors should receive priority for any organ needed

·      Prior living donor priority should not have a time restriction

·      Prior living donors should not be valued differently based on organ donated

·      Prior living donor priority should not be optional to individual candidates

American Society of Transplantation | 09/12/2024

The American Society of Transplantation (AST) offers the following comments in response to the committee update, “Continuous Distribution of Livers & Intestines Update, Summer 2024":

•The AST agrees with using Status 1A, Status 1B, and MELD/PELD as the medical urgency score model for the first version of liver continuous distribution. The Committee’s assessment not to implement a new medical urgency model simultaneously with implementation of the first iteration of liver continuous distribution is prudent, and the AST supports using MELD 3.0 for the medical urgency attribute in this first iteration. The AST remains enthusiastic about the Optimized Prediction of Mortality (OPOM) model’s potential and is in favor of its continued analysis and validation for possible incorporation in liver continuous distribution in the future to weigh other parameters affecting mortality in advanced liver diseases not considered in MELD 3.0.

•The AST suggests continuation of preferential allocation of pediatric grafts to pediatric recipients to improve waitlist mortality among pediatric recipients. The AST supports the Committee’s ongoing work to continue simulation exercises, including the incorporation of pediatric offer filters, for more accurate assessment of modeling results and the expected impact on pediatric liver recipients. The AST also recommends policy that would yield an increased volume of split liver transplants. Simplified allocation allowing pediatric and adult liver programs to collaborate more easily to allocate one segment of a split liver to an appropriate pediatric liver candidate and the remaining segment to an appropriate adult liver candidate would be beneficial.

•With regards to travel efficiency, the choice to fly or drive depends on center practices, population density/traffic patterns, weather, as well as distance. The AST cautions the incorporation of a specific “drive versus fly” metric, unless the intention is to award points based upon a candidate being within a set distance from a donor. Transportation choice hinges on specific practices of transplant centers which are likely diverse and geographically dependent. In general, auto transportation is used for many donors within a one-two hour distance from the transplant center. Current distribution prioritizes geographic distribution in terms of nautical miles from the transplant center, which accounts for this distance. Transplant hospitals in densely populated urban centers may use helicopters for transport even within close proximity, especially during heavy traffic times. The AST encourages the OPTN to consider whether local proximity should have greater impact due to the high cost of transportation on the transplant process. Additional prioritization of livers to local centers, such as those with donor procurement at a recipient hospital, as well as those within the city limits of the transplant center should be explored. This may also improve utilization in instances where local backup could be provided.

Newer technologies (e.g., normothermic regional perfusion, hypothermic machine perfusion) are likely to greatly impact the ability to transport livers over large distances with minimal impact on graft function, even with longer cold ischemic time. Availability of machine perfusion may need to be factored to allow for broader distribution of such organs; however, there are concerns regarding the broad availability and liver program experience with such technologies, which may exacerbate disparities.

•The efforts to increase access to appropriate-sized grafts is appreciated- this is an important consideration to avoid unintended consequences resulting in liver candidates with small body habitus being underserved by the new liver continuous distribution allocation algorithm. The AST has concerns that the body surface area (BSA) alone as an attribute may vary greatly in patients with increased total water volume due to fluid shifts and ascites, resulting in a falsely elevated BSA for candidates with greater ascites. Similarly, obese patients with short stature may have small abdominal domain, but these patients will continue to be underserved due to elevation of their BSA resulting from increased adipose tissue. Further, size matching for a specific donor liver to a recipient involves more than BSA and includes assessing the size of the donor liver, abdominal domain and size of recipient, presence of ascites, primary vs. secondary liver transplant, where does the recipient carries their weight, etc. Additional information detailing the BSA attribute’s impact on waiting list mortality and how the size-based rating scale donor modifier will impact matching pairs of high/low BSA is needed.

•Medically complex donors are currently defined as DCD or age greater than 70. Additional donor factors that could be considered include high BMI, donor instability (e.g., high pressor requirements), prolonged donor hospitalization, significantly elevated donor liver enzymes, intraoperative reallocations, and decreasing the donor age limit to 65 years. All such factors impact the likelihood of organ acceptance and may impact ultimate donor allograft function. Additionally, perhaps a metric such as the Discard Risk Index (DSRI) could be considered and modeled.1

Availability of hypothermic machine perfusion and normothermic regional perfusion may increase the usability of DCD grafts and broaden the recipient population to which these grafts are targeted. As experience increases, use of normothermic regional perfusion for a DCD donor may need to be factored into the utilization efficiency attribute.

•HCC and other oncologic indications for transplant have been recently deprioritized to decrease waitlist mortality among patients with highest biologic MELD. The risk of progression on the waitlist needs to be carefully balanced with prioritization based on medical urgency to optimize organ resource utilization. Given that cancer recipients may often be more appropriate for medically complex donors, increased weight donors, DCD or other extended-criteria donors, may be considered for HCC patients. Additionally, the incorporation of “exception” points into the composite allocation score (versus MELD) as “diagnosis priority points” alleviates the misnomer and associated confusion with exception points given that they indeed follow allocation rules.

HCC stratification has the potential to address the urgency within different tiers of HCC progression, such that a patient is less likely to progress to the point of being disqualified for transplantation. In the current system, waiting time for HCC candidates may still experience significant geographic variability, and some candidates may experience prolonged wait times greater than one year. While the six-month rule generally allows a period of observation to prevent transplanting patients with highly aggressive tumors, prolonged wait-time — particularly beyond 6 months — increases risk for recurrent or de novo disease. The AST suggests the OPTN consider stratification based on tumor size and increased prioritization of HCC patients with prolonged waiting times (e.g., greater than one year) to help prevent non-transplant removals from the waiting list in high waiting time regions.

•The AST believes the following additional considerations warrant Committee discussion:

- The AST agrees with awarding additional points for liver-intestinal candidates within ideal candidate criteria. Due to limited access for intestinal transplant candidates, increased waiting time should be considered due to increased risk for patient mortality.

-Clarification is necessary regarding additional prioritization that will be awarded to the other nine current standard exception categories, and to the non-standard exceptions granted by the National Liver Review Board, meant to equalize mortality risk in at-risk populations.

-In consideration of a population density metric, this could de-prioritize patients listed within a less population dense region, thus inducing geographic disparities. It is unclear how this would contribute to increased access.

-The omission of post-transplant survival metrics in the current model is questionable given the lifesaving nature of liver transplantation and the need to appropriately support ethical principles of allocation. Acknowledging there are currently no reliable patient-level survival estimates, SRTR data could inform the creation of such a metric. If such a model was available, its inclusion would be consistent with allocation principles and the weights in other organ continuous distribution models. The AST recommends taking an approach similar to that employed by the OPTN Heart Transplantation Committee with the continuous distribution of hearts, in which post-transplant survival is maintained as a component of the continuous distribution model for future elaboration.

-Continuous distribution may be a difficult concept for transplant candidates to understand. Development of education documents for liver transplant candidates may improve candidate understanding of the allocation system and their waitlist priority.

1. Rana A, Sigireddi RR, Halazun KJ, et al. Predicting Liver Allograft Discard: The Discard Risk Index. Transplantation. 2018;102(9):1520-1529. doi:10.1097/TP.0000000000002151

Region 9 | 09/10/2024

An online comment stated that typically their program will drive within a 60 mile radius. Regarding utilization efficiency, a member remarked that this would allow for utilization of last minute offers, but that it will require better communication and coordination between the transplant center and the OPO about how likely it is for the patient to become primary on the offer. An attendee commented that patients with smaller tumors should not be given more points, but patients with larger tumors that grow beyond policy criteria should be prioritized.  They continued to say that HCC patients should not be prioritized over patients with a lab MELD over 28, as those patients have a real risk of death if they are not transplanted quickly. A member thought that the risk of drop out for HCC patients could be aligned to the risk of mortality for non-exception patients, with points aligned accordingly.

During the meeting, attendees participated in group discussions and provided the following feedback:  

• Deciding when to fly versus when to drive is dependent on where you are in the country, but no matter the distance, medically urgent patients require more travel and the medical urgency attribute will outweigh proximity. 
• When awarding points for medically complex livers, it may be hard to include biopsy as there is no standardization.  
• HCC is different enough that it might warrant a separate scoring system.  
• Pediatric candidates should be highly prioritized, and the group suggested targeting quality livers to be split for these candidates. 

OPTN Transplant Administrators Committee | 09/04/2024

The OPTN Transplant Administrators Committee appreciates the opportunity to comment on the Liver and Intestines Committee’s Continuous Distribution of Liver Update. The Committee offers the following feedback for consideration:

• The Transplant Administrators Committee wants the Liver and Intestines Committee to keep in mind that the rise of normothermic technologies has significantly increased costs of liver transplants. This trend may reduce the accessibility of transplants for patients at centers that cannot implement such technology due to financial constraints and long-term financial impacts.

Overall, the Committee is supportive of the developments on Liver Continuous Distribution and advises that equity be considered in the development process.

Region 6 | 09/03/2024

During the meeting, in-person attendees participated in group discussions. The liver and intestine group commented that the threshold for when teams fly rather than drive for organ procurement is 120 miles. They also agreed that the definition of a medically complex liver offer should include DCD donors and donors over the age of 70. They added that split livers should also be included in the definition to enhance utilization efficiency. They commented that some of the priorities and weights for travel efficiency and medically complex donors may decrease with the event of normothermic perfusion. The group also discussed exceptions and commented that more work is needed on specific conditions based on post-transplant outcomes. They went on to comment that an important consideration for pediatric patients is the overall mortality on the waiting list (WL). It was noted that 70% of pediatric patients are not transplanted based on their PELD (Pediatric End-Stage Liver Disease) score but through exceptions. Therefore, when reviewing adult exceptions, it is crucial to also consider pediatric exceptions to ensure fair and appropriate allocation for children. 

Virtual attendees also provided feedback on key questions. Some attendees commented that the threshold for when teams fly rather than drive for organ procurement is around 120-150 miles. One attendee commented that flying versus driving is impacted as much by location, particular geography and transportation infrastructure in the country as distance.

Region 1 | 08/29/2024

A virtual attendee commented that regarding the decision to drive versus fly, their program uses ground transportation up to 2-3 hours, anything more than that would be a helicopter or airplane. The attendee also supports fulminant hepatic failure being prioritized over all other medical urgency states. Another comment suggested looking at offer filters data to help identify “hard to place” livers.

During the meeting, attendees participated in group discussions and provided the following feedback:

· Defining when programs decide to fly versus drive is difficult – it’s a nebulous number, dependent on program, whether the liver is being pumped, etc., so group could not settle on an answer.

· There was significant concern that the increased prevalence of machine perfusion, any efficiency metrics established for liver continuous distribution may be out of date by implementation.

· Regarding medically complex liver offers, attendees suggested adding large livers. They also again stated that with perfusion and pumping, these definitions may not be applicable in the future.

· Participants commented that if you’re getting down to sequence 200 on the match, pre-recovery, that might be around the point when expedited placement should be considered.

· The group expressed support for making it easier for conversations between local OPOs and programs for decision-making and expedited placement

UAMS Medical Center | 08/28/2024

After reviewing the Summer 2024 Update on Continuous Distribution of Livers, we appreciate the information and offer the following feedback. When discussing the distance traveled, using nautical miles poses several issues. The time and resources it takes to travel 250 nautical miles will differ for every center/OPO. This does not account for traffic, construction, weather, driver availability, natural landscape limitations, etc. We feel that when discussing medically complex livers, it is critical to allow transplant centers to determine the most suitable match for the organ being offered.

Region 8 | 08/27/2024

Online attendees submitted the following feedback on flying versus driving and travel logistics - anything more than one hour driving the centers’ team will fly (sometimes within their own state if the travel times are increased and weather is a factor), at more than 250 miles, and at more than two hours travel time. Online attendees did not submit feedback on the Utilization Efficiency attribute. And there was support for specific donor modifiers.

During the meeting, attendees participated in group discussions and provided feedback on the following questions:

· Please provide feedback on when your organization begins to fly rather than drive for organ procurement as well as any feedback on travel practices.

o  There was not a clear consensus on the fly versus driving question but there were a lot of considerations taken into account, including FAA restrictions or non-approvals.

· Please provide feedback on the Utilization Efficiency attribute including input on the options for how to award candidates points and the definition of a medically complex liver offer.

o  Attendees in the group were very uncomfortable with individuals getting points for a specific attribute based on center behavior that they are unable to control.

· Please provide feedback on how to incorporate exceptions into the continuous distribution framework, including Hepatocellular carcinoma (HCC) stratification, and whether any specific donor modifiers are necessary.

o  Regarding donor modifiers, the group had pediatric representation at their table and reported the biggest recent impact on pediatric waitlist was prioritizing pediatric donor organs to pediatric candidates as designed in current allocation.

o  Regarding split livers, the group requested reassurance, when possible, organs originally allocated to pediatric patients that are split be allocated to pediatric candidates since pediatric surgeons may be more comfortable splitting livers. 

Region 4 | 08/19/2024

The liver and intestine group commented that they were in agreement that medical urgency should be highly prioritized with other attributes having lesser priority.  When discussing travel efficiency, they agreed that when institutions decide to drive versus fly will be variable in region 4 due to the geography of the region. The group commented that medically complex livers may become easier to place with pumps.  They also discussed how to include HCC stratification and thought one option would be to break this into low risk versus high risk.  They agree that further discussion about this is needed. One attendee strongly advocated for giving priority to prior living donors noting that over the past 25 years, the number of prior living donors who are listed for transplant is very low but has a high impact on promoting trust in the system and is important for how the transplant community connects with the community at large.  

Virtual attendees also provided feedback on key questions.  Several attendees commented that transportation logistics are complex due to geography, weather and availability of planes.

Region 2 | 08/16/2024

Feedback submitted online touched on several points of interest including MELD exception calculations, with curiosity expressed about the outcomes of these calculations. There was also a call for better ways to describe anatomical size, such as height or anteroposterior (AP) diameter, noting that AP diameter is commonly available for both candidates and donors and should be utilized more effectively. Improved organ distribution was highlighted as a key factor that could lead to higher success rates, lower costs, and overall better patient health outcomes. 

During the meeting, attendees participated in group discussions and provided feedback on the following questions: 

• Please provide feedback on when your organization begins to fly rather than drive for organ procurement as well as any feedback on travel practices. 
• The discussion focused on the limitations of using nautical miles (NM) as the sole factor in deciding whether to fly or drive for organ transport. It was emphasized that cold ischemia time (CIT) and overall travel time, including potential delays like traffic, are more critical considerations. While some teams typically fly for rapid recovery, others suggested that time estimates, accounting for rush hour traffic in major cities, should be prioritized over just measuring distances. 
• Please provide feedback on the Utilization Efficiency attribute including input on the options for how to award candidates points and the definition of a medically complex liver offer.  
• The discussion highlighted the importance of internal practices aimed at maximizing the success rate of liver transplants by carefully matching organs to suitable patients. This involves a detailed framework for grading both livers and patients, including assessing biopsies and pump data to ensure the best possible outcomes. There is interest in expanding these practices to other programs to improve access to organs and consider MELD exception points. Additionally, the use of modifiers for donors by some programs and the potential of MELD 3.0 to award candidate points were mentioned as important considerations. 
• Please provide feedback on how to incorporate exceptions into the continuous distribution framework, including Hepatocellular carcinoma (HCC) stratification, and whether any specific donor modifiers are necessary. 
• No comments 

Luke Preczewski | 08/02/2024

The proposal is headed in the right direction, but needs refinement. In particular, definition is needed around travel efficiency, especially drive vs. fly.
An additional efficiency criterion should be added for assessment of whether organs transplantable without machine perfusion are being perfused at high cost to accommodate distant or delayed allocation.
Past changes have led to a system in which far too many unnecessary flights occur. This has dramatically increased logistic challenges and costs for transplant centers and Medicare. Additionally, organs that could be successfully transplanted with lower transportation and perfusion costs are going on machines to go greater distances at astronomical costs. Dry runs are much more frequent, again, increasing costs and taxing limited resources of flights and staff. This trend is not financially or logistically sustainable, and any future changes need to take this seriously. Unfortunately, this proposal does not, and should be revised to address this.