Calculating the Lung Allocation Score Error for ECMO Patients
1University of Chicago, Chicago, IL, 2Vanderbilt University, Nashville, TN, 3University of Wisconsin, Madision, WI
Meeting: 2020 American Transplant Congress
Abstract number: 396
Keywords: Allocation
Session Information
Session Name: Lung: Let's Start at the Beginning: Pre-Transplant Decision Making and Access to Lung Donors
Session Type: Oral Abstract Session
Date: Saturday, May 30, 2020
Session Time: 3:15pm-4:45pm
Presentation Time: 4:27pm-4:39pm
Location: Virtual
*Purpose: The use of extracorporeal membranous oxygenation (ECMO) as a bridge to lung transplantation has increased dramatically. However, the Lung Allocation Score (LAS) does not use a dedicated ECMO variable; instead, ECMO is proxied by mechanical ventilation with 100% oxygen. It is unknown if this approximation accurately reflects the transplantation urgency for ECMO patients.
*Methods: Lung transplant candidates and recipients greater than 12 years of age between 2008-2017 were selected from the SRTR database. For both the wait-list (WL) and post-transplant (PT) time periods, predicted survival functions were calculated using the LAS model and compared to observed survival functions estimated by Kaplan-Meier. Differences between predicted and observed WL scores and PT scores were calculated for candidates and recipients, stratified by ECMO support at listing or transplant. The error in WL and PT scores were then combined to estimate the LAS error for each group.
*Results: During the study period, 24,441 candidates were listed; 473 were on ECMO at listing. A total 18,945 patients were transplanted; 716 were on ECMO at transplant. Non-ECMO candidates survived a mean of 337 days from listing compared to a LAS prediction of 296 days, leading to a WL error of 41 days. ECMO candidates survived a mean of 164 days from listing compared to a LAS prediction of 48 days, leading to a WL error of 116 days. Non-ECMO recipients survived a mean of 336 days from transplant compared to a LAS prediction of 322 days, leading to a PT error of 14 days. ECMO recipients survived a mean of 308 days from transplant compared to a LAS prediction of 258 days, leading to a PT error of 50 days (Fig 1). ECMO was associated with an overestimation of the LAS by 17 points, compared to a non-ECMO overestimation of 6 points.
*Conclusions: The LAS ECMO correction underestimates both WL and PT one-year survival, leading to an overall upward bias in the LAS compared to Non-ECMO candidates. This suggests that ECMO candidates have a lower transplantation urgency than implied by their LAS.
To cite this abstract in AMA style:
Dussault N, Katsis J, Garrity E, Churpek MM, Parker WF. Calculating the Lung Allocation Score Error for ECMO Patients [abstract]. Am J Transplant. 2020; 20 (suppl 3). https://atcmeetingabstracts.com/abstract/calculating-the-lung-allocation-score-error-for-ecmo-patients/. Accessed June 26, 2025.« Back to 2020 American Transplant Congress