Lung transplantation disparities based on diagnosis for patients bridging to transplant on extracorporeal membrane oxygenation

https://doi.org/10.1016/j.healun.2021.08.005Get rights and content

Background

Extracorporeal membrane oxygenation (ECMO) is increasingly utilized as a bridge to lung transplantation, but ECMO status is not explicitly accounted for in the Lung Allocation Score (LAS). We hypothesized that among waitlist patients on ECMO, patients with pulmonary arterial hypertension (PAH) would have lower transplantation rates.

Methods

Using United Network for Organ Sharing data, we conducted a retrospective cohort study of patients who were ≥12 years old, active on the lung transplant waitlist, and required ECMO support from June 1, 2015 through June 12, 2020. Multivariable competing risk analysis was used to examine waitlist outcomes.

Results

1064 waitlist subjects required ECMO support; 40 (3.8%) had obstructive lung disease (OLD), 97 (9.1%) had PAH,138 (13.0%) had cystic fibrosis (CF), and 789 (74.1%) had interstitial lung disease (ILD). Ultimately, 671 (63.1%) underwent transplant, while 334 (31.4%) died or were delisted. The transplant rate per person-years on the waitlist on ECMO was 15.41 for OLD, 6.05 for PAH, 15.66 for CF, and 15.62 for ILD.

Compared to PAH patients, OLD, CF, and ILD patients were 78%, 69%, and 62% more likely to undergo transplant throughout the study period, respectively (adjusted SHRs 1.78 p = 0.007, 1.69 p = 0.002, and 1.62 p = 0.001). The median LAS at waitlist removal for transplantation, death, or delisting were 75.1 for OLD, 79.6 for PAH, 91.0 for CF, and 88.3 for ILD (p < 0.001).

Conclusions

Among patients bridging to transplant on ECMO, patients with PAH had a lower transplantation rate than patients with OLD, CF, and ILD.

Section snippets

Study design, participants, and data sources

This is a retrospective cohort study of all adults and adolescents greater than 12 years old who were active on the waitlist for lung transplant in the United States from June 1, 2015 through June 12, 2020, and who were receiving ECMO support as a bridge to transplantation. The starting date of the study was chosen because UNOS mandated that all sites report data on ECMO status at the time of removal from the waitlist beginning June 1, 2015. Patients were excluded from this study if data were

Patient characteristics

There were 1064 waitlist candidates who required ECMO support as a bridge to lung transplant during the study period and met inclusion criteria (Figure S2). The median age was 52 years (IQR 37-60), and 464 (43.6%) were female. Forty (3.8%) patients had OLD diagnoses, 97 (9.1%) had PAH, 138 (13.0%) had CF, and 789 (74.1%) had ILD. There were notable differences in age, sex, race, ethnicity, body mass index (BMI), and proportion of patients listed for only double-lung transplant across the

Discussion

PAH patients bridged to transplant with ECMO were less likely to be transplanted than patients with OLD, CF, or ILD. This is despite PAH patients having similar post-transplant survival at 1-year compared patients with other diagnoses on adjusted analysis. This study demonstrates that there are disparate waitlist outcomes for patients bridged to transplant with ECMO.

The LAS system is designed to be priority-based and allocate organs according to need and potential benefit; however, it has

Disclosure statement

MA is supported by National Institutes of Health grant: K23 HL150280. This funding is unrelated to this manuscript. The remaining authors have no financial conflicts of interest or financial attachments to disclose in relation to this manuscript.

Author contributions

DF, EBR, SA, and LB were involved in the study conceptualization and design. DF and LB conducted the data analysis, and interpretation, and drafted the manuscript. EBR, LS, HR, MA, HK, DA, CLA, DB, DF, JC, PL, BPS, FD, JRS, and SA were involved in the data analysis and interpretation. All authors reviewed and edited the final manuscript.

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