Advanced Lung Failure and Transplantation
New OPTN/UNOS data demonstrates higher than previously reported waitlist mortality for lung transplant candidates supported with ECMO

https://doi.org/10.1016/j.healun.2023.04.017Get rights and content

Background

The use of extracorporeal membrane oxygenation (ECMO) is not currently incorporated into US allocation models due to the historical lack of complete data in the national US registry which changed in 2016 to include ECMO at the time of waitlist removal and more granular timing and configuration data.

Methods

We studied adult lung transplant candidates from May 1, 2016 to June 1, 2020 with data abstracted from multiple sources in the US Scientific Registry of Transplant Recipients. Waitlist analyses included cumulative incidence functions and Cox proportional hazards models considering ECMO as a time-dependent variable. Post-transplant analyses included Kaplan Meier, Cox proportional hazards models, and observed to expected survival ratios.

Results

A total of 867 candidates were on ECMO prior to transplant; 247 were identified using new sources of data. Candidates on ECMO had a 23.9 increased adjusted likelihood of waitlist removal for being too sick or death, but only a 4.08 increased adjusted likelihood of transplant. Candidates bridged with ECMO who underwent lung transplant (N = 587) experienced an increased overall hazard of post-transplant mortality with veno-arterial and veno-venous configurations conferring hazard ratio (HR) = 1.67 (95% CI, 1.16, 2.40), HR = 1.45 (95% CI, 1.15, 1.82), respectively.

Conclusions

We identified an additional 28.5% of candidates bridged with ECMO prior to transplant using new data. This study of the newly identified full cohort of ECMO candidates demonstrates higher utilization of ECMO as well as an underestimation of waitlist mortality risk factors that should inform strategies to provide timely access to transplants for this population.

Section snippets

Population

All lung transplant candidates listed for lung transplant from May 1, 2016 to June 1, 2020 were identified using data from the Scientific Registry of Transplant Recipients (SRTR).9 The SRTR data system includes data on all donors, waitlisted candidates, and transplant recipients in the US, submitted by the members of the OPTN. The Health Resources and Services Administration, US Department of Health and Human Services provides oversight to the activities of the OPTN and SRTR contractors.

Case adjudication

There were 12,386 lung listings for 11,985 unique lung transplant candidates. After excluding pediatric (N = 246) and multi-organ listings (N = 247), there were 11,492 candidates. 379 candidates had ECMO documented at the time of waiting list placement, and 488 with ECMO implantation between listing and transplant (Total N = 867). 62 candidates had missing ECMO implantation dates and were only included in the waitlist sensitivity analysis and post-transplant survival analyses. Of the 867

Principal findings

Through a detailed case identification process using data newly collected by OPTN/UNOS, we found that ECMO bridging to transplant is more prevalent than previously reported, identifying an additional 28.5% of candidates that were missed using previously available ECMO data. The candidates bridged to transplant with ECMO experienced a 23.9-fold increased risk of becoming too sick to transplant or death yet only experienced a 4.08-fold increased likelihood of receiving a transplant, a discordance

Conclusions

Due to structural changes in ECMO data collection, it is now possible to accurately classify candidates requiring ECMO at all points on the waiting list, allowing for accurate estimation of the waitlist and post-transplant mortality and more accurate predictions of transplant benefit in this population. We found that candidates on ECMO are likely to experience considerable transplant benefit with a high risk of waitlist mortality and relatively well-preserved post-transplant survival; however,

Author Contributions

All authors meet all four ICMJE criteria for authorship. CJL, JS, and MV designed the study, JS acquired the data, JS and SA completed the analysis, and CJL, JS, SA, and MV interpreted data for the work. All authors had full access to data, collaborated to produce the final draft, and accept responsibility to submit for publication.

Acknowledgments

The authors would like to thank Theresa Garcia, MNA, for providing a detailed description of the clinical data entry process for US candidates bridged to transplant with ECMO. The data reported here have been supplied by the Hennepin Healthcare Research Institute (HHRI) as the contractor for the Scientific Registry of Transplant Recipients (SRTR). The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy of or

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  • Cited by (0)

    This project was funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health (Dr Lehr with K08HL159236 and Cystic Fibrosis Foundation 004235A122 and Dr Valapour with R01HL153175) and a research grant from the Cleveland Clinic Center for Populations Health Research.

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    Twitter: @CarliLehrMDPhD, @MValapour

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