Identification and Characterization of Patients With a Mixed Phenotype of CLAD

Abstract

Purpose Bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS), have been identified as main phenotypes of chronic lung allograft dysfunction (CLAD), however patients can change phenotype. We aimed to describe incidence, prognosis, radiology, pulmonary function and pathology in this mixed group of CLAD. Methods We retrospectively assessed the chest CT-scans of all double lung patients transplanted between 2001 and 2015 with a FEV1 decline >20% of baseline. The diagnosis of RAS was made using a decline in TLC>10% compared to baseline or a decline in FVC>20% compared to baseline. A mixed group of CLAD was defined as patients developing a TLC or FVC decline with persistent CT opacities after initial CLAD diagnosis (without TLC or FVC drop) or vice versa. Results 44% of the patients developed CLAD (268/608) of which 77 developed persistent CT opacities (29%). 45 patients were immediately diagnosed with RAS. We found twenty-seven patients with a mixed phenotype of CLAD (25 BOS to RAS, 2 RAS to BOS). In 5 patients persistent pleuroparenchymal opacities were found without an additional decrease in FVC or TLC. The median time between CLAD and mixed diagnosis was 2Y (IQR 0.9-4.8Y). Median survival after CLAD diagnosis was longer in the mixed group compared to the RAS group (4.3Y vs 1.17, p=0.0052), however survival after the appearance of opacities was similar in both groups (p=0.39). We found significantly more emphysema patients in the mixed group (p=0.0062), with a lower FEV1 (p Conclusion We demonstrated that 35% of patients showed a mixed phenotype of CLAD, which showed difference in survival, demographics, pulmonary function, radiology and pathology compared to RAS patients.