Endobronchial ultrasound in study of airway wall remodeling in COPD patients

INTRODUCTION Chronic obstructive pulmonary disease (COPD) is a heterogenous disease which is characterized by chronic inflammation and irreversible airflow obstruction. One of the cause of progression of COPD is associated with small airway wall thickening, which has been suggested as a result of remodeling. Two methods are used to assess the remodeling, one being histological examination of bronchial biopsies and the other - computed tomography. New and promising radiologic method is endobronchial ultrasonography (EBUS) that enables the assessment of the bronchial wall layers. Using EBUS it is possible to discern 5 layers in trachea and cartilaginous bronchi. AIMS AND OBJECTIVES Application of EBUS in assessment of the remodeling in COPD. METHODS 33 patients with COPD (9 female, 24 male, mean age 66,8 ± 8,8 years, mean FEV 1 : 57,8 ± 22,3% of predicted value), 15 patients with severe asthma and 15 control subjects. In all patients spirometry before and after β 2 -agonist and EBUS with measurements of bronchial wall layers were performed. RESULTS The mean thickness of bronchial wall layers in COPD patients were: L 1 - 0,135±0,018 mm, L 2 -0,151±0,026 mm, L 3-5 - 0,906±0,065 mm. There was no correlation between the thickness of bronchial wall layers and FEV 1 . The thicknesses of bronchial wall layers in COPD were statistically smaller than in severe asthma and slightly higher than in control group. CONCLUSIONS The significant differences in bronchial wall layers thickness in COPD and severe asthma and no correlation between bronchial wall layers and pulmonary function tests observed only in COPD patients suggest different mechanism responsible for remodeling and bronchial obstruction in this disease.