Clinical Characteristics of Severe Refractory Asthma Associated with the Effectiveness of Bronchial Thermoplasty

We investigated the clinical characteristics of refractory asthma associated with the effectiveness of bronchial thermoplasty (BT). We retrospectively evaluated data from 10 patients who underwent BT between June 2016 and December 2017 at Okayama Medical Center. The following were measured before and 6 months post-BT: forced expiratory volume in 1.0 s (FEV1), fractional exhaled nitric oxide (FeNO), immunoglobulin E (IgE) level, blood eosinophil counts (Eosi), Asthma Quality of Life Questionnaire (AQLQ) score, and preventive medication use. At baseline, the mean post-bronchodilator FEV1 was 80.9% of the predicted value (range 45.6-115.7%). All patients were being treated with moderate- or high-dose inhaled corticosteroids and long-acting β2 agonists. The AQLQ improved from 4.26±1.67 at baseline to 5.59±0.94 at 6 months post-BT (p<0.05). The %FEV1, FeNO, IgE, and Eosi did not change significantly between baseline and 6 months post-BT. No severe complications were reported. BT was effective for non-allergic and non-eosinophilic in 3 patients, and allergic or eosinophilic in 4 patients. Their AQLQ improved by > 0.5 points post-BT. For both allergic and eosinophilic asthmatics following mepolizumab, BT was not useful. BT was effective for non-allergic and non-eosinophilic or allergic asthmatics, but insufficient for both allergic and eosinophilic following mepolizumab.