Tracheal meandering may predict prognosis in idiopathic pleuroparenchymal fibroelastosis: a retrospective observational study

In cases of progressive idiopathic pleuroparenchymal fibroelastosis (iPPFE), the entire lung is suspended above the thorax. This causes the tracheal bifurcation to elevate upward and the trachea to meander. In this study, we aimed to investigate the association between tracheal meandering and the prognosis of iPPFE. We retrospectively collected data from 41 patients diagnosed with iPPFE between April 2009 and December 2021 and evaluated chest radiograph at the diagnosis of iPPFE. The angle and length/height cutoff values were 23° and 63 mm/m, respectively. The median survival time (MST) was significantly longer in patients with an angle of 23° or less (89 months) than in those with an angle over 23° (24 months). The MST was also significantly shorter in patients with a length/height of 63 mm/m or less (33 months) than in those over 63 mm/m (89 months). Multivariate analysis did not show a statistically significant association between the angle and death within 24 months; however, a possible trend was observed. In conclusion, calculating tracheal excursion using only chest radiograph is a straightforward process that may be useful in predicting the prognosis of iPPFE.