Risk Assessment of Chronic Lung Allograft Dysfunction Phenotypes after Living-Donor Lobar Lung Transplantation According to the 2019 ISHLT Classification System

Purpose Chronic lung allograft dysfunction (CLAD) is known as one of the major fatal disorders in the long-term phase after lung transplantation. Because CLAD is a heterogeneous disease, proper classification of phenotypes is important to understand each pathogenesis. In this study, we retrospectively evaluated the impact of new 2019 ISHLT classification system on living-donor lobar lung transplantation (LDLLT). Methods Between 1998 and 2019, a total of 96 patients underwent LDLLT at our hospital, and 73 patients who underwent bilateral LDLLT were included in this study. CLAD after bilateral LDLLT were diagnosed and classified according to the ISHLT consensus report in 2019. Results The median follow-up time was 10.3 years. A total of 27 (37.0%) patients were diagnosed as CLAD, including bronchiolitis obliterans syndrome (BOS) (n = 8, 29.6%), restrictive allograft syndrome (RAS) (n = 11, 40.7%), mixed (n = 1, 3.7%), undefined (n = 2, 7.4%), and unclassified (n = 5, 18.5%). CLAD developed in the unilateral lung in 26 patients. Five-year survival of the patients developing CLAD after LDLLT was 84.1%, whereas 5-year survival of the patients after CLAD onset was 58.4%. Survival after CLAD onset was worse in the patients with RAS (p=0.008) and undefined (p=0.003) than those with BOS. Though survival after CLAD onset did not differ between the patients with or without CT opacities (p=0.40), the patients with restriction on pulmonary function test had significantly worse survival than those without restriction (Figure, p=0.001). Conclusion While the patients with BOS had better prognosis, the presence of restriction on pulmonary function test could predict worse prognosis of the CLAD patients after bilateral LDLLT.