Development of the New Lung Allocation System in the United States

TLDR

The new lung allocation system in the United States has evolved through a complex and controversial process, with debate emphasizing allocation based on medical urgency and transplant survival rather than waiting time. The system replaces waiting‑time priority with a composite score that balances urgency (expected lifetime without a transplant) and benefit (difference in expected lifetime with versus without a transplant), using clinical and demographic data that can be updated as patients’ conditions change, and is reviewed every six months with potential incorporation of new risk factors and community feedback. The debate was published in Chest (2005; 128:407‑415).

Abstract

The development of the new system for lung allocation in the United States has been a complex and at times controversial process (20Egan TM Kotloff RM. Pro/Con debate: Lung allocation should be based on medical urgency and transplant survival and not on waiting time..Chest. 2005; 128: 407-415Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar). Lung allocation is no longer based on waiting time; it now balances a measure of waiting list urgency (expected lifetime without a transplant) and a measure of transplant benefit (the difference between expected lifetime with versus without a transplant). The urgency and benefit measures are estimated from clinical measurements and demographic data. When potential recipients' clinical condition changes, their data can be updated and their score will change accordingly. Because the population of patients waiting and the risks of waiting list mortality and posttransplant mortality may change with time, the system is intended to be modified as often as every 6 months, based on analysis of the most recent 3-year cohort of patients. Any new risk factors identified by these analyses can be incorporated into future iterations of the allocation system. In addition to regular reviews, the Lung Subcommittee has recommended that the system be reviewed at a forum with the lung transplant community at a suitable time after implementation for feedback and suggestions for refinement.