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A7746 - Novel Endoscopic Techniques for Patients with Severe Asthma and Airway Stenosis
Author Block: J. Faul1, C. M. Burke2, W. Shah3, L. Cormican3, l. thong1; 1Dept of Respiratory Medicine, Asthma Research Centre, Dublin, Ireland, 2Dept of Respiratory Med, Connolly Hosp, Dublin 15, Ireland, 3connolly hospital, Dublin, Ireland.
Introduction: When subjects with severe asthma fail to respond to conventional asthma therapy, it may be important to consider the presence of an acquired or congenital airway stenosis. Airway strictures can remain undiagnosed for some years, because the symptoms and signs of a stenosis mimic asthma. Moreover, the symptoms of asthma can be more difficult to quantify because tracheal and bronchial stenosis can cause persistence of the characteristic symptoms of asthma: wheeze and shortness of breath. However, while airway obstruction due to asthma generally responds quickly to bronchodilator and steroid therapy, airway obstruction due to a stenosis may prove resistant to systemic corticosteroid and/or biologic therapy. Methods: We prospectively performed fiberoptic bronchoscopy on 452 adults with asthma that was classified as “difficult to treat”. In two cases there was a long segment of tracheal stenosis associated with aberrant right upper lobe takeoff from the lower trachea (congenital anomaly). One further case had a benign stricture of the distal end of the left mainstem bronchus, and another case had almost complete stenosis of the origin of the right middle lobe bronchus. The latter two cases were successfully treated using a novel drug delivery catheter called the Blowfish® Transbronchial Micro-Infusion Catheter (Mercator MedSystems, Emeryville, CA). Using a flexible bronchoscope, we introduced a flexible, balloon-tipped catheter that contained a microneedle. The design of the catheter allows injection directly into the airway wall through the microneedle when the balloon is inflated. In both cases of bronchial stenosis we were able to successfully deliver dexamethasone 4mg directly into the area of stenosis via a microneedle port. In the first case the FVC increased from 77% to 104%, FEV1 increased from 40% to 68%, and FEV1/FVC increased from 0.43 to 0.55. The second case required two catheter-directed dexamethasone injections to open the orifice of the right middle lobe. The FVC increased from 106% to 114%, FEV1 from 95% to 103%, and the FEV1/FVC remained stable at 75%. These two cases of bronchial stenosis in the setting of asthma have required neither antibiotic nor systemic corticosteroids in the 6 months following catheter-directed therapy. Conclusion: Novel flexible fiberoptic bronchoscopy techniques can help to diagnose and treat areas of localized airway stenosis in patients with “difficult to treat” asthma. In our experience, when asthma and an airway stenosis co-exist, aggressive local treatment of the stenosis, using catheter-directed therapy, can significantly improve airflow limitation and asthma control.