Understanding the mechanism of bronchial thermoplasty using airway volume assessed by computed tomography

Bronchial thermoplasty (BT) is a recent treatment for moderate-to-severe asthma in which the airway smooth muscle (ASM) layer is targeted directly using thermal energy delivered during bronchoscopy. Although direct targeting of the ASM is appealing because of its role in bronchoconstriction in asthma, BT is not widely used because direct physiological effects after treatment (e.g. changes forced expiratory volume in 1 s (FEV1) or the concentration of methacholine required to decrease FEV1 by 20%) have not been shown consistently [1–3]. Instead, clinical response is demonstrated through indirect measurements, such as improved Asthma Control Questionnaire (ACQ) and Asthma Quality of Life Questionnaire scores, and reduced use of rescue medication [1, 2], acknowledging that there is also a considerable placebo component [3]. These findings leave doubt about the efficacy and mechanism of action of BT. Recent work, however, has demonstrated a direct change in a new physiological measure, namely airway volume assessed by high-resolution computed tomography (CT) [4].
High-resolution CT assessment of airway volumes after bronchial thermoplasty (BT), together with model predictions regarding the efficacy and underlying mechanism of action of the treatment, combine to help to elucidate the underlying mechanism of BT http://bit.ly/2WPHY6y