Survival and functional outcomes of single lung transplantation in secondary pulmonary hypertension.

Background: The role of single lung transplantation (SLT) in secondary pulmonary hypertension (SPH) remains controversial. This study evaluated the feasibility and long-term outcomes of SLT in patients with SPH-defined as mean pulmonary artery pressure ≥25 mmHg measured by right heart catheterization immediately before transplantation-within Japan's allocation system, characterized by protracted waiting periods.

Methods: We retrospectively reviewed 83 deceased-donor lung transplantations, categorized into four groups: SLT without SPH (n = 14), SLT with SPH (n = 19), bilateral lung transplantation (BLT) without SPH (n = 12), and BLT with SPH (n = 38). Outcomes analyzed included 5-year survival, CLAD-free survival, and exercise tolerance.

Results: At transplantation, 68.6 % of recipients exhibited SPH, a significant increase compared to registration. Among SLT recipients, the SPH group demonstrated 5-year survival (83.2 %) and CLAD-free survival (65.9 %) not inferior to those of the non-SPH group (50.0 % and 56.8 %, respectively). Perfusion ratios and 6-min walk distances remained comparable between SPH and non-SPH groups for up to five years. Additionally, 5-year survival (83.2 % vs. 81.1 %) and CLAD-free survival (65.9 % vs. 64.5 %) were similar between SLT and BLT. High preoperative oxygen requirements were associated with poorer early graft function in SPH patients receiving SLT. No definitive predictors of CLAD or long-term survival were identified.

Conclusions: SLT is a viable option for patients with mild-to-moderate SPH, providing survival and functional outcomes comparable to BLT. Careful recipient and donor selection remains essential, particularly given the risk of SPH progression during extended waiting periods.