Waitlist outcome differences for pulmonary hypertension patients are worse in the CAS era

Background: Patients with pulmonary hypertension (PH) have previously experienced worse waitlist outcomes than peers with other diagnoses. In 2021, the Lung Allocation Score (LAS) was revised to improve the prediction of expected survival. The Composite Allocation Score (CAS) was subsequently implemented in 2023. The effects of these changes on waitlist outcomes for patients with PH are not known. Methods: A retrospective analysis of the United Network for Organ Sharing database was performed in 3 eras: LAS Era 1 (November 24, 2017-September 30, 2021), LAS Era 2 (October 1, 2021-March 8, 2023), and CAS Era (March 9, 2023-June 27, 2024). Unadjusted and adjusted competing risks regression analyzed waitlist outcomes within each era comparing diagnosis groups, and for PH patients across eras. Results: Adjusted waitlist mortality for PH patients was worse relative to chronic obstructive pulmonary disease (COPD) and cystic fibrosis in LAS Era 1, not significantly different from other groups in LAS Era 2, and worse relative to COPD and interstitial lung disease in the CAS Era. Waitlist mortality for PH patients was unchanged between the LAS Eras and the CAS Era. Transplantation rate for PH patients was improved in the CAS Era compared to LAS Era 2, when measures of right heart dysfunction were removed from the LAS calculations, but not compared to LAS Era 1. Conclusion: In the CAS Era, PH patients continue to experience increased waitlist mortality relative to non-PH diagnoses. Waitlist mortality for PH patients has not improved in the CAS Era compared to the LAS Eras.