Abstract
Bronchial thermoplasty induces atrophy of the airway smooth muscle layer, but the mechanism whereby this improves patient health is unclear. In this study, we use computed tomography (CT) to evaluate the effects of bronchial thermoplasty on airway volume 12 months post-procedure.
10 consecutive patients with severe asthma were evaluated at baseline by the Asthma Control Questionnaire (ACQ), and high-resolution CT at total lung capacity (TLC) and functional residual capacity (FRC). The CT protocol was repeated 4 weeks after the left lung had been treated by bronchial thermoplasty, but prior to right lung treatment, and then again 12 months after both lungs were treated. The CT data were also used to model the implications of including the right middle lobe (RML) in the treatment field.
The mean patient age was 62.7±7.7 years and forced expiratory volume in 1 s (FEV1) 42.9±11.5% predicted. 12 months post-bronchial-thermoplasty, the ACQ improved, from 3.4±1.0 to 1.5±0.9 (p=0.001), as did the frequency of oral steroid-requiring exacerbations (p=0.008).
The total airway volume increased 12 months after bronchial thermoplasty in both the TLC (p=0.03) and the FRC scans (p=0.02). No change in airway volume was observed in the untreated central airways. In the bronchial thermoplasty-treated distal airways, increases in airway volume of 38.4±31.8% at TLC (p=0.03) and 30.0±24.8% at FRC (p=0.01) were observed. The change in distal airway volume was correlated with the improvement in ACQ (r=−0.71, p=0.02). Modelling outputs demonstrated that treating the RML conferred no additional benefit.
Bronchial thermoplasty induces long-term increases in airway volume, which correlate with symptomatic improvement.
Abstract
CT scanning was used to evaluate patients undergoing bronchial thermoplasty. CT demonstrated that treatment increased airway volume, and this persisted for 12 months and correlated with improved symptoms. https://bit.ly/350YNBD
Footnotes
Support statement: D. Langton was the recipient of a post-graduate research scholarship from Monash University; and P.B. Noble was supported by a Western Australian Department of Health Merit Award, and a Medical and Health Research Infrastructure Fund. Studies examining physiological mechanisms of bronchial thermoplasty are supported by NHMRC of Australia (APP1180854). No industry funding was received.
Author contributions: D. Langton designed this study, recruited all patients, performed all bronchial thermoplasty procedures and analysed the data. C. Banks performed all patient assessments. G.M. Donovan performed the model simulations and assisted with data analysis. G.M. Dononvan, P.B. Noble, V. Plummer and F. Thien assisted with manuscript preparation and intellectual input in relation to study outcomes and findings.
Availability of data and materials: The datasets used during the current study are available from the corresponding author on reasonable request
Conflict of interest: D. Langton has nothing to disclose.
Conflict of interest: C. Banks has nothing to disclose.
Conflict of interest: P.B. Noble has nothing to disclose.
Conflict of interest: V. Plummer has nothing to disclose.
Conflict of interest: F. Thien has nothing to disclose.
Conflict of interest: G.M. Donovan has nothing to disclose.
- Received May 24, 2020.
- Accepted August 21, 2020.
- Copyright ©ERS 2020
This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.