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A1625 - Usual Interstitial Pneumonia Pattern in the Lower Lung Lobes as a Prognostic Factor in Idiopathic Pleuroparenchymal Fibroelastosis
Author Block: K. Kono1, M. Kato1, T. Nakamura1, T. Yamada1, M. Tajima1, H. Ihara1, K. Tajima1, S. Shiota1, F. Takahashi1, S. Sasaki2, K. Seyama1, K. Takahashi1; 1Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan, 2Juntendo Univ Urayasu Hosp, Chiba, Japan.
Rationale Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is known as a rare interstitial pneumonia and characterized by stiffness in both the upper lobes and pleura on high resolution computed tomography (HRCT) of the chest. However, prognostic factors have not been identified for IPPFE. We aimed to investigate clinical prognostic factors affecting survival in patients with IPPFE. Methods Between April 2009 and September 2017, we enrolled 30 patients who were clinically diagnosed with IPPFE by HRCT. The HRCT findings in IPPFE were defined as bilateral apical pleural thickening, thickening of the interlobular septa, and traction bronchiectasis in both upper lobes. Patients with collagen tissue disease, hypersensitivity pneumonia, and pneumoconiosis were excluded from this study. These patients were classified into either the death (dead within 24 months from the diagnosis of IPPFE) or survival (survived greater than 24 months) group. We retrospectively analyzed the clinical characteristics, serum markers, pulmonary function test results, and HRCT findings. However, pulmonary function tests could not be performed in 5 patients with pneumothorax along with the diagnosis of IPPFE. Results Fourteen patients were classified into the death group, due to progressive disease or respiratory failure, and the others into the survival group. On admission, there were no significant differences in smoking history, degree of weight loss, performance status, presence of any infections, oxygen saturation, serum marker levels (including surfactant protein-D [SP-D] and sialylated carbohydrate antigen KL-6 [KL-6]), and pulmonary function test results (including focal vital capacity [FVC], diffusing capacity of lung carbon monoxide [DLCO], and higher residual volume to total lung capacity [RV/TLC] ratio) between the two groups. At diagnosis, the incidence of coexistence of a usual interstitial pneumonia (UIP) pattern in the lower lobe on HRCT in the death group was significantly higher than that in the survival group. Then, the incidence of pneumothorax during follow-up phase in the death group was significantly higher than that in the survival group. Multivariate analysis revealed that a UIP pattern in the lower lobe on HRCT was an only independent variable for poor prognosis (p = 0.005). The median survival time from diagnosis in patients with IPPFE was 24 months (95% confidence interval: 17.89-30.11). In patients with IPPFE, the survival time with a UIP pattern was significantly shorter than in those without a UIP pattern (hazard ratio: 18.88, p = 0.001). Conclusion Our findings suggest that a UIP pattern in lower lobs at diagnosis was the independent prognostic factor for IPPFE.