Greater Large Conducting Airway Luminal Area in Patients with Interstitial Lung Disease

Interstitial lung disease (ILD) encompasses multiple pulmonary disorders characterized by damaged pulmonary tissue caused by a sequence of inflammation and fibrosis. While much is known about ILD-associated changes within the parenchyma and the pathophysiological processes underpinning the disruption of pulmonary dynamics and gas exchange, less is known about ILD-associated changes of luminal area within the large conducting airways. We aimed to investigate whether luminal area of the large conducting airways is different between patients with ILD and healthy controls. In a retrospective case-control study, luminal areas of seven large conducting airways were measured using three-dimensional reconstructions of computed tomography imaging. Patients with ILD (N=82; 54% female) were compared to control subjects matched for age, sex, and height. Univariate ANOVA tests or Kruskal-Wallis tests were used to analyze group and sex differences. Patients with ILD had greater large conducting airway luminal areas than control subjects for measured large conducting airways, including the trachea (296±73 vs. 247±65 mm², P<0.001), right main bronchus (214±59 vs. 161±46 mm², P<0.001), bronchus intermediate (123±32 vs. 94±28 mm², P<0.001), right upper lobe (81±22 vs. 61±20 mm², P<0.001), left main bronchus (151±41 vs. 119±35 mm², P<0.001), left lower lobe (71±22 vs. 48±15 mm², P<0.001), and left upper lobe (86±21 vs. 68±22 mm², P<0.001). Among patients with ILD, males had 17-34% greater luminal areas (normalized to height) than females depending on the airway segment (all P<0.05).