Implications for the CAS system for organ distribution in the United States: Implementing the System.

The change to a continuous distribution of lungs and the composite allocation score (CAS) in March 2023 aims to improve access to lung transplant and reduce waiting list mortality. Early data post implementation shows that it has achieved this aim and, in some areas, exceeded expectations. Waiting list mortality has declined31% in the 6 months post-implementation, and the waiting time for organs has improved overall (a decrease of 14%). Significant improvements in waiting time are seen for pediatric and younger patients, sensitized patients and non- group O patients. Improvement in the equitable distribution of organs to racial and ethnic minorities has also been observed. These benefits have occurred without significant negative results, as waiting list mortality has either reduced or not been affected, across most subgroups. The net effect of these changes has been to align transplant rates with that of the overall recipient pool, promoting equity in organ distribution consistent with the principles set for organ allocation in the Final Rule from the Department of Health and Human Services. Removal of geographic boundaries to donors has resulted in increased travel for organs with potentially increased cost. Work should focus on improving the efficiency of organ procurement. Centralized donor centers, utilization of local procurement surgeons and use of organ storage and transport devices may ameliorate the costs involved and improve organ utilization. Ongoing monitoring of the effects of CAS implementation is required, but early experience has shown that continuous distribution has provided a net benefit to lung transplant candidates.