Characterization of baseline lung allograft dysfunction in single lung transplant recipients

<bold>Background:</bold> Baseline lung allograft dysfunction (BLAD) is characterized by the failure to achieve near-normal lung function after lung transplantation (LTX). In double lung transplant (DLTX) recipients, BLAD patients have a high risk of mortality compared to patients with normal baseline lung function. In single lung transplant (SLTX) recipients, cut-off values and associated factors have not been explored. Here, we aimed to define BLAD in SLTX recipients, investigate its impact on allograft survival and identify potential risk factors for BLAD in SLTX recipients. <bold>Methods:</bold> We performed a retrospective, single-center analysis of the LTX cohort of LMU Munich between 2010 and 2018. In accordance with DLTX cut-offs, BLAD in SLTX recipients was defined as failure to achieve FEV1% and FVC% of greater than 60% on two consecutive tests more than three weeks apart. Survival analysis as well as regression analysis for potential predictors of BLAD were performed. <bold>Results:</bold> In a cohort of 141 SLTX recipients, 40% of patients met BLAD criteria. SLTX recipients with BLAD demonstrated impaired survival. Donor/recipient lung size mismatch was associated with BLAD in obstructive and restrictive lung disease. Pulmonary function testing at a 3 months timepoint after lung transplantation predicted baseline lung function. <bold>Conclusion:</bold> BLAD in SLTX recipients is as relevant as in DLTX recipients and should generally be considered in the follow-up of LTX recipients. Risk factors for BLAD differed between underlying obstructive and restrictive lung disease. A better understanding of associated factors may help in the development of preventive strategies.