Background: Donor lungs are preferentially offered to patients within a local geographic area before being offered to a broader region. This algorithm may prevent patients from accessing appropriately matched donors due to their geographic location. Leveraging simulation software, we hypothesize broader geographic sharing of donor lungs could decrease waitlist time and increase the Lung Allocation Score (LAS) at the time of transplant. The LAS is a clinical acuity score used to prioritize patients; higher scores reflect a higher priority for transplant.

Methods: Our study population included all US lung transplant candidates and donors from July 1, 2009, through June 30, 2011. The thoracic simulated allocation model, a computer allocation simulation program, was developed by the Scientific Registry of Transplant Recipients. Each simulation was repeated 10 times using actual donors in random order. Since the same donors and candidates were used in each simulation and were not independent samples, statistical tests of comparisons were not possible. Instead, the average and the minimum–maximum range of results for the 10 iterations were described.

Simulation 1 used current allocation rules which prioritizes local allocation; simulation 2 removed local allocation and first offered donor lungs to transplant centers within a 500 nautical mile (nm) radius; simulation 3 removed local allocation and first offered donor lungs to transplant centers within a 1,000 nm radius.

Results: The simulations showed: average waitlist time was 5.32 months (5.16-5.47), 4.61 months (4.49-4.70), and 4.73 months (4.69-4.79) for simulations 1, 2, and 3, respectively. LAS at time of transplant was 46.63 (46.47-46.75), 48.39 (48.19-48.50), and 48.86 (48.62-49.18) for simulations 1, 2, and 3, respectively.

Conclusions: Broader geographic sharing can lower waitlist time and increase the LAS at the time of transplant. Our findings may be explained by broader geographic sharing increasing access to appropriately matched donors for waitlisted patients, therefore shortening wait times. The rise in LAS could be attributed to more high acuity patients accessing transplant. Implementing broader sharing at 500 nm (simulation 2) had more impact than extending broader sharing from 500 nm to 1,000 nm (simulation 3). Further study is needed to assess the role of broader geographic sharing in increasing access to lung transplant, and the impact of transplanting more patients at a higher LAS.

CITATION INFORMATION: Tsuang W., Budev M. Broader Geographic Sharing and Impact on Lung Transplant Waitlist Time and Lung Allocation Score Am J Transplant. 2017;17 (suppl 3).

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