Continuous Distribution of Livers & Intestines Update, Summer 2024
At a glance
Background
In December 2018, the OPTN Board of Directors approved the continuous distribution framework for allocation of all organs. Continuous distribution will rank waiting list candidates based on points related to various factors, such as medical urgency, post-transplant survival, candidate biology, patient access, and placement efficiency. Continuous distribution will remove the boundaries between classifications and will increase equity for candidates and transparency in the system.
This concept paper provides an overview of the project’s development, progress to date, and next steps for continuous distribution of liver and intestines. The paper requests community feedback that will assist the Liver and Intestinal Organ Transplantation Committee’s work.
Supporting media
Presentation
Requested feedback
- Feedback on the identified attributes as well as their drafted purposes.
- Feedback on the Committee’s decision to utilize MELD and PELD as the medical urgency score model within the first version of continuous distribution.
- Feedback specific to the pediatric population within liver continuous distribution.
- Feedback on when organizations begin to fly rather than drive for organ procurement.
- Feedback on how to incorporate utilization efficiency as an attribute.
- Feedback on any other aspects of this project including any additional considerations that are not addressed in this paper.
Anticipated impact
- What it's expected to do
- Provide a more equitable approach to matching candidates and donors
- Remove hard boundaries between classifications that prevent candidates from being prioritized higher on the match run
- Establish a system that is flexible enough to work for each organ type
- What it won't do
- This paper is not a proposed policy change but will help the Liver and Intestinal Organ Transplantation Committee develop a future policy proposal
Terms to know
- Attributes: Attributes are criteria we use to classify then sort and prioritize candidates. For example, in liver allocation, criteria include model for end-stage liver disease (MELD) or pediatric end-stage liver disease (PELD) score, blood type compatibility, distance between donor hospital and transplant program, and others.
- Composite Allocation Score: A composite allocation score combines points from multiple attributes together. This concept paper proposes the use of composite allocation scores in a points-based framework.
- Rating Scale: A rating scale describes how much preference is given to candidates within each attribute.
- Weights: Weights reflect the relative importance or priority of each attribute in the overall composite allocation score. Combined with the ratings scale and each candidate’s information, this results in an overall composite score for prioritizing candidates.
- Mathematical Optimization: A tool that starts with specific outcomes and then finds policy scenarios with relative weights that will accomplish those desired outcomes.
- Organ Allocation Simulator (OASim) Modeling: A tool that models the potential impact of specific developed policy scenarios.
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Read the full proposal (PDF)
Provide feedback
Comments
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.