Extrapulmonary Problems Limit the Outcome of Lung Transplantation in Idiopathic Pleuroparenchymal Fibroelastosis: A Multi-Center Study in Japan

Abstract

Idiopathic pleurparenchymal fibroelastosis (IPPFE) is a relatively new disease entity of interstitial pneumonia characterized by upper lobe dominant fibrosis and flat chest. The purpose of this study is to evaluate the outcome of lung transplantation for IPPFE in comparison with idiopathic pulmonary fibrosis (IPF). We retrospectively reviewed patients with IPPFE and those with IPF aged 20 or over who underwent lung transplantation between 1998 and 2018. Data were collected from all nine lung transplant centers in Japan, under the support of Japanese Society of Lung and Heart-Lung Transplantation. One hundred patients were eligible, including 31 IPPFE and 69 IPF patients. Patients with IPPFE were more likely to be women (58% vs 28%; P < 0.01) and to have a significantly lower body mass index (BMI) (17.6±3.6 vs 22.6±4.2 kg/m2; P < 0.01) than those in the IPF group. Kaplan-Meier survival curves showed no significant difference in overall survival between groups (P = 0.66; Figure 1A). The stay in the intensive care unit (ICU) was significantly longer in the IPPFE group (22.8±19.15 vs 13.2±11.2 days; P < 0.01). In the IPPFE group, BMI did not improve even 1 year after transplant (pre-; 16.5±3.2 kg/m2 vs 2 years later; 15.6±2.5 kg/m2; P = 0.08). By two years after transplantation, percent predicted forced vital capacity in IPPFE group significantly improved (pre-; 36.9±17.2 vs 2 years later; 52.0±20.0 %; P = 0.03; Figure 1B). However, compared with the IPF group, the value was still significantly lower (52.0±20.0 vs 70.8±18.7 %; P < 0.01). The survival of patients with IPPFE after lung transplantation was comparable with those with IPF. However, patients with IPPFE showed longer ICU stay, limited improvement in pulmonary function, and no improvement in low BMI, suggesting systemic or extrapulmonary problems such as stiff chest wall in patients with IPPFE.