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

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.

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.

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.

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.