Determinants of Baseline Lung Allograft Dysfunction and its Long-term Impact on Pulmonary Function After Bilateral Lung Transplantation.

Abstract

Background: Lung transplantation (LT) is the definitive treatment for selected end-stage lung diseases, yet some recipients fail to achieve normal pulmonary function posttransplant, a condition known as baseline lung allograft dysfunction (BLAD). Its causes and long-term outcomes remain incompletely understood.

Methods: We retrospectively analyzed all adult bilateral LT performed between 2014 and 2019, with follow-up through December 2024. BLAD was defined as failure to achieve forced expiratory volume in 1 s and/or forced vital capacity ≥80% predicted within the first post-LT year. Multivariable logistic regression identified risk factors, and Cox and linear mixed-effects models assessed associations with survival, chronic lung allograft dysfunction (CLAD), and lung function trajectories.

Results: Among 325 recipients, BLAD occurred in 65.5% and was independently associated with reduced survival (hazard ratio, 5.25; 95% confidence interval, 3.84-7.18; P  < 0.001). BLAD was associated with increased CLAD risk in the overall cohort (hazard ratio, 1.42; 95% confidence interval, 1.00-2.00; P  = 0.047), although this association was attenuated after excluding recipients with structural or mechanical causes of reduced spirometry. Risk factors included higher body mass index, longer intensive care unit stay, bronchial stenosis, and older donor age. Over 5 y, BLAD recipients exhibited slower spirometry decline than recipients achieving normal baseline function, whereas CLAD was the main determinant of long-term functional deterioration.

Conclusions: BLAD is common after LT and is associated with increased mortality and lower long-term pulmonary function. The BLAD-CLAD association may be partly confounded by structural or mechanical causes of reduced spirometry, supporting BLAD as a heterogeneous early post-LT phenotype.