Comparison of bronchiolitis obliterans syndrome to other forms of chronic lung allograft dysfunction after lung transplantation

Abstract

Background: The radiographic presence of allograft infiltrates is atypical of bronchiolitis obliterans (BO) and inconsistent with the definition of bronchiolitis obliterans requires that restrictive processes are ruled out. The natural history of these other forms of chronic allograft dysfunction has not been well characterized. We examined the prognostic significance of radiographic and spirometric restrictive processes in comparison to BOS among lung transplant recipients.

Methods: We performed a retrospective review of lung transplant recipients with chronic lung allograft dysfunction (CLAD) as defined by spirometry. Subgroups based on the presence or absence of persistent radiographic abnormalities were labeled as non-specific (CLAD-NS) and CLAD due to BOS (CLAD-BOS), respectively. The CLAD-BOS group was further divided into obstructive (OBOS) and restrictive (RBOS) phenotypes based on spirometry. Groups were compared with respect to survival and decline in forced expiratory volume in 1 second (FEV(1)).

Results: Among 241 lung transplant recipients, 96 (40%) were identified as having CLAD, of whom 62 (65%) had CLAD-BOS and 34 (35%) CLAD-NS. No difference between groups was identified with respect to post-CLAD survival or decline in FEV(1). CLAD-BOS subgroups included 35 (56%) patients with OBOS and 27 (44%) with RBOS. There was no difference in these subgroups with respect to survival or subsequent FEV(1) decline.

Conclusions: Patients with CLAD and persistent radiographic infiltrates have a similar prognosis to BOS patients but may still represent a clinically distinct phenotype. BOS patients frequently exhibited a restrictive pattern on spirometry, which also did not offer further prognostic information, but could still represent a unique disease phenotype.