Assessment of Airway Remodeling Using Endobronchial Ultrasound in Asthma-COPD Overlap

Abstract

Karolina Górka,1,2 Iwona Gross-Sondej,1,2 Jacek Górka,3 Tomasz Stachura,1,2 Kamil Polok,1,3 Natalia Celejewska-Wójcik,1,2 Sławomir Mikrut,4 Anna Andrychiewicz,5 Krzysztof Sładek,1,2,* Jerzy Soja1,2,* 1Department of Pulmonology and Allergology, University Hospital, Kraków, Poland; 2 2nd Department of Internal Medicine, Jagiellonian University Medical College, Kraków, Poland; 3Centre for Intensive Care and Perioperative Medicine, Jagiellonian University Medical College, Kraków, Poland; 4Faculty of Mining Surveying and Environmental Engineering, AGH University of Science and Technology, Kraków, Poland; 5Department of Endoscopy, University Hospital, Kraków, Poland*These authors contributed equally to this workCorrespondence: Jerzy Soja 2nd Department of Internal Medicine, Jagiellonian University Medical College, ul Jakubowskiego 2, Kraków, 30-688, PolandTel [phone]Fax [phone]Email [email protected]: The aim of this study was to evaluate the structural changes of the airways using the endobronchial ultrasound (EBUS) in ACO patients compared to severe asthma and COPD patients.Patients and Methods: The study included 17 patients with ACO, 17 patients with COPD and 33 patients with severe asthma. Detailed clinical data were obtained from all participants. Basic laboratory tests were performed, including measurement of eosinophil counts in blood and serum immunoglobulin E (IgE) concentrations. All patients underwent spirometry and bronchoscopy with EBUS (a 20‑MHz ultrasound probe) to measure the total thicknesses of the bronchial walls and their particular layers in segmental bronchi of the right lower lobe. EBUS allows to distinguish five layers of the bronchial wall. Layer 1 (L1) and layer 2 (L2) were analyzed separately, while the outer layers (layers 3– 5 [L3– 5]) that correspond to cartilage were assessed together.Results: In patients with ACO the thicknesses of the L1 and L2 layers, which are mainly responsible for remodeling, were significantly greater than in patients with COPD and significantly smaller than in patients with severe asthma (median L1= 0.17 mm vs 0.16 mm vs 0.18 mm, p< 0.001; median L2= 0.18 mm vs 0.17 mm vs 0.20 mm, p< 0.001, respectively). The thicknesses of the total bronchial walls (L1+L2+L3– 5) and L3– 5 were significantly smaller in ACO and COPD patients compared to asthma patients (median L1+L2+L3– 5= 1.2 mm vs 1.14 mm vs 1.31 mm, p< 0.001; median L3– 5= 0.85 mm vs, 0.81 mm vs 0.92 mm, p=0.001, respectively).Conclusion: The process of structural changes in the airways assessed by EBUS is more advanced in individuals with ACO compared to patients with COPD, and less pronounced compared to patients with severe asthma. It seems that EBUS may provide useful information about differences in airway remodeling between ACO, COPD and severe asthma.Keywords: asthma-COPD overlap, airway remodeling, total bronchial wall, bronchial wall layers, endobronchial ultrasound

Keywords

• asthma-copd overlap
• airway remodeling
• total bronchial wall
• bronchial wall layers
• endobronchial ultrasound