PURPOSE:Excessive dynamic expiratory central airway collapse (EDAC) results from an exaggerated protrusion of the posterior membrane into the airway lumen causing a decrease in the cross-sectional area of more than 50%. This condition is accompanied by signs and symptoms that mimic asthma and COPD. Recent advances in diagnostic studies and the development of new multidimensional classification systems permitted the differentiation of this condition from tracheobronchomalacia based on the morphology of airway abnormalities. To date there are no studies evaluating spirometric testing and bronchodilator response in affected patients.
METHODS:A prospective analysis was performed of patients with bronchoscopically-proven EDAC who underwent spirometric testing prior to airway evaluation between November 2006 and February 2008. Patients had symptoms of expiratory wheezing, cough and dyspnea on exertion. Controls were randomly selected from the same database and had bronchoscopically proven normal airway anatomy.
RESULTS:Thirty one patients met inclusion criteria, 11(35.5%) with diagnosed EDAC in the study group and 20(64.5%) with a normal airway bronchoscopic exam in the control group. There was no significant difference in age. The groups were also similar in race distribution, BMI and smoking status. There were more females than males in the EDAC group. EDAC presented with a normal FEV1/FVC ratio versus the control group having a decreased mean ratio (76.2 vs 63.5) P value=0.04. Also the mean FEF 25–75 predicted was higher in the EDAC group (67%) versus the mean in the control group (28%) P value=0.03. After bronchodilator response testing there were no statistically significant changes between the two groups although there was a trend for more bronchodilator response in the control group versus the patients with EDAC.
CONCLUSION:EDAC demonstrated a spirometric parameter characterized by a normal FEV1/FVC ratio and a higher FEF25–75 than controls which was statistically significant; this was associated with a trend of less bronchodilator responsiveness during our study which differentiates this condition from asthma and COPD.
CLINICAL IMPLICATIONS:Spirometry could assist in differentiating EDAC from symptomatic asthma and COPD.
DISCLOSURE:Jaime Molina, No Financial Disclosure Information; No Product/Research Disclosure Information