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Each organ type's final continuous distribution policy will be adopted by the OPTN Board of Directors, and will comply with NOTA and the OPTN Final Rule.
Lung continuous distribution took effect March 9, 2023. What you need to know about OPTN lung policy changes.
The Organ Procurement and Transplantation Network is developing a more equitable system of allocating deceased donor organs. The new approach is called continuous distribution.
The goals of the new continuous distribution framework are consistent with allocation requirements in the National Organ Transplant Act (NOTA) and the OPTN Final Rule.
This new framework is being designed to allow multiple factors that contribute to a successful transplant to be considered simultaneously as part of the organ offer process.
Right now, a classification-based system of organ allocation is in place. The current system gives points to candidates at various steps of a sequence in the organ offer process. Candidates are transplant patients who are waiting for an organ to be offered to them.
That can mean that when certain candidate characteristics, called attributes, are reviewed in sequence, sometimes patients are placed on one side of a hard boundary that stops them from being prioritized further on the match run. The match run is the list that is generated when an organ donor’s information is entered into the national waiting list computer system, to identify potential recipients.
Some examples of a candidate’s attributes or factors include:
The current system that matches organs with patients gives points to candidates at various steps of a sequence in the organ offer process.
In this broad example, there are four candidates who are being prioritized for an organ offer: Candidates A, B, C and D.
These patients vary in terms of their:
In the current classification system, any single factor could potentially determine the order in which these candidates are prioritized in a match run.
For example, if the order of prioritization were to be based first on distance, then Candidate C would receive an offer first, followed by A, B and D.
But if priority is given to the patient’s medical urgency, then Candidate B would receive the first offer, followed by A, D and C.
As this example shows, the current classification-based system sometimes places patients on one side of a hard boundary that stops them from being prioritized further, because patient factors aren’t considered together.
The new continuous distribution framework will dissolve the hard boundaries that exist in the current classification-based system. Importantly, continuous distribution is flexible enough to apply to all organ types.
Continuous distribution will change organ allocation by:
Working organ type by organ type, through research and analysis, the donation and transplantation community is working together to design this framework to determine patient priority in the match run.
Continuous distribution will change how patients are prioritized. Continuous distribution will consider all patient factors togethe to determine the order of an organ offer, and no single factor will decide an organ match. The goal is to increase fairness by removing the hard boundaries that are part of the classification-based system.
Every organ type will have its own formula to calculate how candidates on the waiting list are prioritized. Depending on the formula that is chosen for a specific organ type, Candidate B in the example above may be the first to receive an offer based on a combination of high medical urgency, medium survival probability and moderate distance from the donor location.
All the factors will be considered together, but every factor will also be weighted. Depending on the weighting of the various factors, the remaining order in the example above may be A, C and D. Candidate C, with the shortest distance from the donor hospital, might appear ahead of Candidate D, who has medium medical urgency but is the farthest from the donor location.
Patients in the continuous distribution system will receive a composite allocation score. Attributes related to a patient’s overall score include medical urgency, expected post-transplant outcome, candidate biology, patient access and efficiency of organ placement.
A higher score puts a patient closer to the top of a match run and more likely to receive an organ transplant.
Every organ type will have a specific set of attributes which will align with the goals of continuous distribution such as prioritization of the sickest candidates and increasing transplant opportunities for patients who are medically harder to match.
Visit each organ type’s continuous distribution page to learn about their specific attributes and the goals they support.
Lung Kidney and pancreas Liver and intestine Heart
In this general match run example (not specific to any organ type):
Candidates receive points from multiple attributes and are unique to each organ offer. In this match run example, Lauren received the most points.
In today’s allocation system, some attributes define allocation classifications. Meaning, if candidates have one of those defining attributes—for example, if they have a very rare blood type—then they will receive priority over otherwise similarly-situated candidates.
In the new continuous distribution framework, each attribute will have a specific weight, and are added together to make one composite allocation score that can change with every organ offer. A candidate’s total score will determine their prioritization on the match run.
Input will come from patients and recipients, donors and their families, and transplant professionals. Everyone has a voice.
During this process, the community will have the chance to take part in online values exercises to help decide how organ attributes are weighted and prioritized.
Many decisions have to be made to develop the new system and achieve improvements for the entire donation and transplantation community. These decisions involve multiple stakeholders – patients, their loved ones, and donation and transplant professionals. Each organ-specific committee will move through the steps below to develop a policy proposal. The proposal will open for public comment before it is submitted to the Board for final approval.
Community input happens at each phase of development to help shape the new system. Here are the steps we’ll take:
This is an important first step. In each organ type’s continuous distribution framework, each attribute will be considered uniquely with regard to each candidate. Each candidate will receive points that are calculated into an overall score. Before that can happen, we must look at how candidates are currently grouped and prioritized for organ allocation. For each attribute, the committee will identify the desired policy outcomes and metrics of success.
The next step is to convert the organ type’s existing allocation policy into the new framework. The OPTN uses several different methodologies to develop these frameworks. Depending upon the organ, this can include a combination of the following steps:
Scientific Research and Transplant Registry (SRTR) modeling and results: The SRTR works with the OPTN to provide analytic support for policy development. Their researchers will take the proposed policies and model them to understand how they could impact candidates. This will help identify any potential unintended consequences or harmful outcomes. The SRTR modeling results will also estimate the benefit of the new proposal and inform any needed improvements.
This step involves considering the community input received, modeling and analysis, as well as the committee project work, to develop and propose a new composite score as a policy proposal for public comment. See details around the policy development process, including public comment.
After the Board of Directors approves the proposal with the new framework, plans for implementation begin.
As each organ moves into continuous distribution, implementation of the approved policies is projected to take approximately 12 months due to the range of changes, required education to the community, and expected impact.
The continuous distribution framework will be flexible enough to apply to all organ types. Using the same framework for all organs will improve organ allocation by creating consistency and transparency for the entire transplant community.
The current organ matching process is different for each organ type. To develop a framework that works for each organ, we will look at each organ type individually.
| Organ | Expected start |
|---|---|
| Lung Implemented March 9, 2023 | January 2019 |
| Kidney and pancreas | June 2020 |
| Liver & intestine | December 2021 |
| Heart | January 2023 |
| Vascularized Composite Allograft | To be determined |
Continuous distribution is the future of organ allocation. Your input is critical to the process of developing a consistent framework that is best for patients.
The entire community can participate in several ways:
These exercises are helping inform the development of the framework for each organ type. Participants are asked to compare two attributes against each other and select their level of importance when considering a candidate for organ transplant. This information will be used to inform the weight of each attribute and the overall score.
We encourage all members of the donation and transplantation community, including donors, patients and their loved ones, to participate in these important values exercises.
Each organ type will have a values exercise. The results of the exercises will be used to inform each organ committee as they develop frameworks for each organ type. The methodology, Analytic Hierarchy Process (AHP), has been used effectively by other healthcare groups to involve patients in making clinical decisions.
| Organ | AHP exercise |
|---|---|
| Lung | Was open during summer 2020 public comment and closed on Oct. 1, 2020. |
| Kidney | Was open during winter 2022 public comment and closed on March 23, 2022. |
| Pancreas | Was open during winter 2022 public comment and closed on March 23, 2022. |
| Heart | Was open during winter 2024 public comment and closed on March 19, 2024. |
In December 2018, the OPTN approved a continuous distribution model as a framework for developing future organ allocation policy, upon the recommendation of a specially called Ad Hoc Geography Committee. Continuous distribution was selected after consideration of multiple alternative frameworks and was developed with input from the public and the transplant community. Recent changes to organ allocation have been made in an effort to align with this new framework and improved equity in organ allocation. Visit the Ad Hoc Geography Committee page for more information about their recommendations.
The process of determining how organs are distributed. Allocation includes the system of policies and guidelines that ensure that organs are distributed in an equitable, ethical and medically-sound manner.
Rules established by the OPTN to guide and regulate organ allocation and distribution in the U.S.
A multi-criteria decision-making methodology. The OPTN is using AHP to help gather information for the development of continuous distribution. Participants in AHP exercises are asked to make decisions about the relative importance of organ attributes when compared to each other.
An attribute is a quality or characteristic of something. In organ allocation, attributes are criteria used to classify and sort and prioritize candidates. For example, in lung allocation, attributes include medical urgency, travel mode, ischemic time, blood type compatibility, and others. Each organ type will have its own attributes in continuous distribution.
A person registered on the organ transplant waiting list.
A classification-based framework groups similar candidates into classifications or groupings. Candidates are then sorted within those classifications. A candidate will only appear in the classification that is most beneficial to them. This is the framework currently used to allocate organs.
The amount of time an organ spends being preserved after recovery from the donor.
A composite allocation score combines points from multiple attributes together. Continuous distribution uses composite allocation scores in a points-based framework.
The way something is shared across a group or area.
The collection of policies and procedures used to distribute organs. Examples include concentric circles and continuous distribution.
A computerized ranking of transplant candidates based on donor and candidate medical compatibility and criteria defined in OPTN policies.
A points-based framework gives each candidate a score or points. Organs are then offered in descending order based on the candidate’s score. Continuous distribution of organs involves a points-based framework.
Weights are the relative importance or priority of each attribute toward our overall goal of organ allocation.