Ibrahim, Mohamed

Abstract Background: Expiratory central airway collapse (ECAC) is defined by excessive inward bulging of either posterior tracheobronchial membrane or anterolateral cartilage. ECAC commonly coexists with COPD, asthma, GERD, and obstructive sleep apnea. ECAC association with bronchiectasis is yet to be documented. Common conditions leading to bronchiectasis are obstructive lung diseases predisposing to recurrent infections, cystic fibrosis, COPD, or idiopathic. This study aims to evaluate the occurrence of bronchiectasis in patients with ECAC as the primary outcome and the correlation between the severity of bronchiectasis and the severity of ECAC as a secondary outcome. Methods: A retrospective single-center study evaluated patients diagnosed with ECAC using dynamic bronchoscopy in Mayo Clinic, Florida, from June 2019 to December 2020. Radiologists analyzed dynamic, or non-contrast chest computed tomography (CT) scans to evaluate the presence of bronchiectatic changes and the prevalence of bronchiectasis in this population. Bronchiectatic changes were documented using the Brody scoring system which recorded the bronchiectasis size, extent and tree in bud appearance in individual lobes. The final score had a range from 0 to 72. The bronchiectasis scores for individual lung lobes were analyzed to interpret distribution of bronchiectasis in ECAC population. The combined bronchiectasis scores of severe ECAC and non-severe ECAC cohorts were compared to assess if severe ECAC had higher bronchiectatic involvement. Results: Out of the 166 patients diagnosed with ECAC through dynamic bronchoscopy, 133 patients (80.1%) presented bronchiectatic changes in their CT scans. Of the 59 patients with severe ECAC, 51 patients (86.4%) were diagnosed with bronchiectasis. Of the 107 patients with non-severe ECAC, 82 (76.6 %) had bronchiectasis. The mean bronchiectasis scores are greater in right and left lower lobes, followed by middle lobes. The median values between severe and non-severe ECAC were 3 and 3 respectively with a p value of 0.34. The inter quartile range was 9 in severe ECAC group and 6 in non-severe ECAC (graph 1). Discussion: The outcomes of this study showed a significant presence of bronchiectatic changes in the ECAC population, implying the importance of evaluating for other pathologies. It can signify a pathological process similar to other pathologies which predispose to recurrent infections except for cystic fibrosis, which has an upper lobe involvement. The correlation of severity between ECAC and bronchiectasis requires more studies with a larger cohort for significant outcomes.