Comparison of Lung Transplant (LTx) Waitlist Outcomes Between Primary Pulmonary Hypertension and other Group B Diagnoses

Document Type

Conference Proceeding

Publication Date

2025

Publication Title

American Journal of Respiratory and Critical Care Medicine

Abstract

Rationale: In patients with advanced and refractory pulmonary vascular disease (PVD), LTx is a lifesaving therapeutic option. Precise assessment of risk on the waitlist is important for the allocation of donor lungs. Historical studies of the Lung Allocation Score (LAS) utilized by the United Network for Organ Sharing (UNOS) have shown increased waitlist mortality and prolonged time to transplant for candidates with pulmonary vascular disease (PVD; Group B) relative to other diagnoses. The LAS does not differentiate between Primary Pulmonary Hypertension (PPH) and other types of PVD.

Methods: Our goal was to assess differences in waitlist outcomes between PPH and other Group B diagnoses. Adult candidates listed for lung transplant in the UNOS database between May 2005 and May 2021 were included. Time to death or transplant within one year of listing was compared between the two groups with competing events analysis.

Results: Our study identified 1741 candidates: 997 PPH and 744 with other Group B diagnoses (GpB). The latter was predominantly composed of Scleroderma 44%, Secondary Pulmonary Hypertension 36% and Pulmonary Veno-occlusive Disease 12%. The PPH Group was younger (47±14 vs. 53±11 y) with fewer males (26% vs. 38%). Despite worse hemodynamics in the PPH group with higher mean pulmonary artery pressure (53.6 vs 40.2 mm of Hg), lower cardiac index (2.7 vs 3 l/min), higher pulmonary vascular resistance (10.4 vs. 6.6 WU), all P< 0.001), the LAS score was comparable (38.8 vs 39.5). After one year of listing, the cumulative incidence function of death or removal from the list was 17% for PPH patients compared with 12% for Group B subjects (P=0.004 by Gray's test), while that of transplant 60% and 71%, respectively(P< 0.001). Although both groups had similar one year survival at 86%, the PPH group had higher 30-day mortality, a greater incidence of grade 3 primary graft dysfunction and need for dialysis, and increased proportion on ECMO and mechanical ventilation at 72 hours.

Conclusion: Lung transplant candidates with PPH have waitlist outcomes inferior to other pulmonary vascular diseases. Early post-operative complications appear higher in PPH subjects, while 1-yr survival post-transplant are similar. Allocation systems should have better predictive power to delineate pulmonary hypertension diagnoses for improved stratification of risk on the waitlist.

Volume

211

First Page

A1859

Last Page

A1859

Comments

American Thoracic Society International Conference, May 16-25, 2025, San Francisco, CA

DOI

10.1164/ajrccm.2025.211.Abstracts.A1859

ISSN

1535-4970

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