The Lung Allocation Score and Its Relevance

Abstract

Lung transplantation in the United States, under oversight by the Organ Procurement Transplantation Network (OPTN) in the 1990s, operated under a system of allocation based on location within geographic donor service areas, wait time of potential recipients, and ABO compatibility. On May 4, 2005, the lung allocation score (LAS) was implemented by the OPTN Thoracic Organ Transplantation Committee to prioritize patients on the wait list based on a balance of wait list mortality and posttransplant survival, thus eliminating time on the wait list as a factor of prioritization. Patients were categorized into four main disease categories labeled group A (obstructive lung disease), B (pulmonary hypertension), C (cystic fibrosis), and D (restrictive lung disease/interstitial lung disease) with variables within each group impacting the calculation of the LAS. Implementation of the LAS led to a decrease in the number of wait list deaths without an increase in 1-year posttransplant survival. LAS adjustments through the addition, modification or elimination of covariates to improve the estimates of patient severity of illness, have since been made in addition to establishing criteria for LAS value exceptions for pulmonary hypertension patients. Despite the success of the LAS, concerns about the prioritization, and transplantation of older, sicker individuals have made some aspects of the LAS controversial. Future changes in US lung allocation are anticipated with the current development of a continuous distribution model that incorporates the LAS, geographic distribution, and unaccounted aspects of organ allocation into an integrated score.

Preoperative evaluation of pulmonary hypertension in lung transplant candidates: echocardiography versus right heart catheterization

“…The measurement of pulmonary artery systolic pressure (PASP) is the clinically relevant parameter since it is used in the pre-transplant lung allocation score. The latter aims to direct organs towards the 'right' patient on the waiting list based on a balance of short-term mortality and post-transplant survival, and it’s use has been to proven to decrease the number of deaths of patients on the wait list [ 3 , 9 , 10 ].…”

Validation of the risk stratification score in idiopathic pulmonary fibrosis: study protocol of a prospective, multi-centre, observational, 3-year clinical trial

“…An encouraging finding was that multi-dimensional indices (RISE, CPI and GAP) proved their effectiveness even in patients undergoing LTx assessment [ 9 ], with an accuracy in predicting mortality similar to the Lung Allocation Score, which is commonly used to evaluate patients on LTx waiting lists, but is much more complex to calculate [ 48 , 49 ].…”

The Surplus Transplant Lung Allocation System in Italy: An Evaluation of the Allocation Process via Stochastic Modeling

“…Several countries have introduced the use of a scoring system to maximize the clinical matches between the tissue type of the donor and that of the recipient. The most used worldwide is the lung allocation score (LAS) [ 6 ], which was introduced in 2005 in the United States by the OPTN [ 7 ]; it gives a score to each candidate based on medical urgency and expected post-transplant survival [ 8 ]. In the US, the lung allocation system is now changing: In the continuous distribution model, they are incorporating the LAS and the geographic distribution [ 7 ].…”

“…The most used worldwide is the lung allocation score (LAS) [ 6 ], which was introduced in 2005 in the United States by the OPTN [ 7 ]; it gives a score to each candidate based on medical urgency and expected post-transplant survival [ 8 ]. In the US, the lung allocation system is now changing: In the continuous distribution model, they are incorporating the LAS and the geographic distribution [ 7 ]. A modified version of the LAS was introduced in 2009 in Europe by Eurotransplant, a network that consists of Austria, Belgium, Croatia, Germany, Hungary, Luxembourg, Netherlands, and Slovenia [ 9 ].…”

“…A modified version of the LAS was introduced in 2009 in Europe by Eurotransplant, a network that consists of Austria, Belgium, Croatia, Germany, Hungary, Luxembourg, Netherlands, and Slovenia [ 9 ]. The utilization of this scoring system has achieved an initial decline in waiting list times and an increase in lung transplantation rates [ 7 , 10 ]. Other European countries have preferred to introduce different priority algorithms to reduce waiting list times and mortality rates, especially in patients with critical conditions.…”