Establish Continuous Distribution of Lungs

At a glance

Current policy

The current system allocates lungs by placing candidates into categories that are arranged by priority. Sometimes a candidate’s category places them on the side of a hard boundary that would prevent them from appearing higher on the match run. Continuous Distribution is a proposed allocation system that considers multiple patient and donor attributes all at once with an overall score. This overall score includes medical urgency, patient outcomes, biological make-up, and other candidate factors and efficiency of organ placement.

Learn how it works

Presentation to the OPTN Patient Affairs Committee about how continuous distribution works

Presentation

View presentation

Proposed changes

• Remove current classification system and replace with a lung composite allocation score which is comprised of the following attributes:
  • Post-Transplant Outcomes, or how long a patient is expected to live after receiving a transplant
  • Medical Urgency, or how long a patient is expected to live without receiving a transplant
  • Biological Disadvantages, for patients who are medically harder to match which includes candidate blood type, sensitization, and height
  • Patient Access, for patients under the age of 18 and patients who are prior living donors
  • Placement efficiency, or the resources required to match, transport, and transplant an organ which includes both travel efficiency and proximity efficiency
• Each attribute has a rating scale, which will determine how many points a candidate receives for each
• Each attribute has a relative weight. The total weights add up to 100
• These points combine into a total score for the candidate
• With every organ offer, a candidate receives a new Composite Allocation Score (CAS), which is used to rank the candidates

Anticipated impact

• What it's expected to do
  • Remove hard boundaries that prevent candidates from being prioritized higher on the match run
  • Reduce waitlist deaths
  • Decrease the number of lungs that are transported via airplane
  • Increase transplant opportunities for pediatric candidates
• What it won't do
  • Change allocation of other single organ transplants

Themes

• Attributes
• Weight of attributes
• Multi-organ allocation
• Exception review process

Terms to know

• Composite Allocation Score (CAS): The total number of points assigned to a candidate on the wait list, which would determine their rank on a match run.
• Rating Scale: Method used to calculate number of points awarded to candidates for each attribute. For example, if everything else is equal, should a candidate with twice as much medical urgency as another receive twice as many points? Applying the rating scale to each candidate’s information and combining it with the weight of the attribute results in an overall composite score for prioritizing candidates.

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