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Standardize Six Minute Walk for Lung Allocation

eye iconAt a glance

Current policy

Six-minute walk distance factors into the lung composite allocation score (CAS). The distance (measured in feet) that a lung candidate can walk in six minutes factors into both the medical urgency and post-transplant outcome portions of the lung CAS. OPTN Policy does not include specifics on conducting these tests, so how these tests are performed varies among programs. This proposal includes a policy change, a guidance document, and data definition changes.

Supporting media

View presentation PDF link

Proposed changes

  • Policy change:
    • Require lung transplant programs to perform an oxygen titration test prior to a patient’s first six-minute walk test
  • Guidance:
    • Creates a guidance document for lung transplant programs to help supplement clinical guidelines
  • Data definition changes:
    • Update the six-minute walk distance data definition to match the policy changes and guidance

Anticipated impact

  • What it's expected to do
    • Provide guidance to create more consistency between programs in how the six-minute walk is conducted
  • What it won't do
    • Change how the six-minute walk impacts the CAS
    • Create a policy that outlines exactly how to conduct the six-minute walk

Terms to know

  • Six-minute Walk Test: A test that helps assess a lung transplant candidate’s cardiopulmonary function. The patient is asked to walk as far as they can in six minutes.
  • Composite Allocation Score (CAS): A composite allocation score combines points from multiple attributes together. The score determines a candidate’s place on the match run.
  • Oxygen Titration Test: A test to evaluate a patient’s oxygen needs when at rest and during exercise.

Click here to search the OPTN glossary

Read the full proposal (PDF)

Provide feedback

eye iconComments

Anonymous | 02/22/2024

I somewhat agree with standardizing the six minute walk test for lung allocation. I think the test will show who may be in greater need for a lung transplant. But, people who perform better in the test and shown to have better cardiopulmonary function than others may not have as high of priority for lung donation. Just because they may have better cardiopulmonary function doesn't mean they should potentially have lower priority.

Neeraj Sinha | 01/26/2024

I support the proposal to standardize 6MW for lung allocation.

• Do you support the proposed policy requirement to perform an oxygen titration test ahead of
the initial six-minute walk test for candidates at least 12 years old, and for candidates
approaching 12 years of age? Yes

• Should policy specify a timeframe within which the oxygen titration test must be completed
ahead of the six-minute walk test? Somewhere within preceding 6 - 12 weeks, ideally within preceding 6 weeks)

• If the policy change were to go into effect on September 5, 2024, would that give lung
transplant programs adequate time to prepare for implementation? Yes

• Are the data definition changes clear, and would you recommend any changes? Yes and no.

• Is the guidance clear, and would you recommend any changes?

No, and yes

I agree with using zero feet as default for patients on ECMO and/or continuous mechanical ventilation, but please consider adding guidance for what needs to be done for a patient who is on high flow O2 and is in an intermediate care or intensive care unit. Such a patient can not safely undergo 6MWT in pulmonary laboratory, and the unit hallway is not optimal for this test: severity of disease and risk of severe desaturations, distractions, obstacles, inability to have 100 feet long obstacle-free path in an IMCU/ICU. I would suggest using "20 feet" as the default value for patients on high flow O2; as arguably the patients on high flow O2 are healthier than patients on continuous mechanical ventilation and/or ECMO where default is to assign zero feet.

• Does this proposal strike the right balance between promoting data quality for the six-minute
walk distance and managing burden on lung candidates and lung transplant programs?


• What, if any, consideration should be given for altitude for candidates who live at a significantly
different altitude compared to the transplant hospital where they are registered?

Some consideration should be given. By gestalt: Addition or reduction of O2 flow by 1 l/m can be done for every 750 m increase or decrease in elevation respectively between oximetry study and 6MWT locations.

Samuel Kirton | 01/23/2024

I am not clear how this is different from the current standard described in ICD 94618. Are you prescribing something that is not in the ICD? If not, would it be simpler to have the centers work to the billing standard required under the ICD?