Project description:ObjectivesBronchial thermoplasty (BT) is a device-based treatment for subjects ≥18 years with severe asthma not well controlled with inhaled corticosteroids and long-acting beta-agonists. The Bronchial Thermoplasty Global Registry (BTGR) collected real-world data on subjects undergoing this procedure.DesignThe BTGR is an all-comer, prospective, open-label, multicentre study enrolling adult subjects indicated for and treated with BT.SettingEighteen centres in Spain, Italy, Germany, the UK, the Netherlands, the Czech Republic, South Africa and Australia PARTICIPANTS: One hundred fifty-seven subjects aged 18 years and older who were scheduled to undergo BT treatment for asthma. Subjects diagnosed with other medical conditions which, in the investigator's opinion, made them inappropriate for BT treatment were excluded.Primary and secondary outcome measuresBaseline characteristics collected included demographics, Asthma Quality of Life Questionnaire (AQLQ), Asthma Control Test (ACT), medication usage, forced expiratory volume in one second and forced vital capacity, medical history, comorbidities and 12-month baseline recall data (severe exacerbations (SE) and healthcare utilisation). SE incidence and healthcare utilisation were summarised at 1 and 2 years post-BT.ResultsSubjects' baseline characteristics were representative of persons with severe asthma. A comparison of the proportion of subjects experiencing events during the 12 months prior to BT to the 2-year follow-up showed a reduction in SE (90.3% vs 56.1%, p<0.0001), emergency room visits (53.8% vs 25.5%, p<0.0001) and hospitalisations (42.9% vs 23.5 %, p=0.0019). Reductions in asthma maintenance medication dosage were also observed. AQLQ and ACT scores improved from 3.26 and 11.18 at baseline to 4.39 and 15.54 at 2 years, respectively (p<0.0001 for both AQLQ and ACT).ConclusionsThe BTGR demonstrates sustained improvement in clinical outcomes and reduction in asthma medication usage 2 years after BT in a real-world population. This is consistent with results from other BT randomised controlled trials and registries and further supports improvement in asthma control after BT.Trial registration numberNCT02104856.

Project description:PurposeBronchial thermoplasty is approved in many countries worldwide as a non-pharmacological treatment for severe asthma. This review summarizes recent publications on the selection of patients with severe asthma for bronchial thermoplasty, predictors of a beneficial response and developments in the procedure and discusses specific issues about bronchial thermoplasty including effectiveness in clinical practice, mechanism of action, cost-effectiveness, and place in management.ResultsBronchial thermoplasty is a treatment option for patients with severe asthma after assessment and management of causes of difficult-to-control asthma, such as nonadherence, poor inhaler technique, comorbidities, under treatment, and other behavioral factors. Patients treated with bronchial thermoplasty in clinical practice have worse baseline characteristics and comparable clinical outcomes to clinical trial data. Bronchial thermoplasty causes a reduction in airway smooth muscle mass although it is uncertain whether this effect explains its efficacy since other mechanisms of action may be relevant, such as alterations in airway epithelial, gland, and/or nerve function; improvements in small airway function; or a placebo effect. The cost-effectiveness of bronchial thermoplasty is greater in countries where the costs of hospitalization and emergency department are high. The place of bronchial thermoplasty in the management of severe asthma is not certain, although some experts propose that bronchial thermoplasty should be considered for patients with severe asthma associated with non-type 2 inflammation or who fail to respond favorably to biologic therapies targeting type 2 inflammation.ConclusionBronchial thermoplasty is a modestly effective treatment for severe asthma after assessment and management of causes of difficult-to-control asthma. Asthma morbidity increases during and shortly after treatment. Follow-up studies provide reassurance on the long-term safety of the procedure. Uncertainties remain about predictors of response, mechanism(s) of action, and place in management of severe asthma.

Project description:BackgroundThe effectiveness of bronchial thermoplasty (BT) has been reported in patients with severe asthma. This study compared the effects of BT and cryoballoon ablation (CBA) therapy on the airway smooth muscle (ASM).MethodsEight healthy male beagle dogs were included in this experiment. In the preliminary experiment, one dog received BT treatment for both lower lobe bronchus, another dog received CBA treatment for 7 s on the upper and lower lobe of right bronchus, and 30 s on the left upper and lower lobe. The treatments were performed twice at an interval of 1 month. In subsequent experiments, the right lower lobe bronchus was treated with BT, and the left lower lobe bronchus was treated with CBA. The effects of treatment were observed after 1 (n = 3) month and 6 months (n = 3). Hematoxylin-eosin staining, Masson trichrome staining, and immunohistochemical staining were used to compare the effects of BT and CBA therapy on the ASM thickness, collagen fibers synthesis, and M3 receptor expression after treatment. One-way analysis of variance with Dunnett post hoc test was used to analyze the differences among groups.ResultsIn the preliminary experiment, the ASM ablation effect of 30-s CBA was equivalent to that of 7-s CBA (ASM thickness: 30.52 ± 7.75 μm vs. 17.57 ± 15.20 μm, P = 0.128), but the bronchial mucociliary epithelium did not recover, and large numbers of inflammatory cells had infiltrated the mucosal epithelium at 1-month post-CBA with 30-s freezing. Therefore, we chose 7 s as the CBA treatment time in our follow-up experiments. Compared with the control group (35.81 ± 11.02 μm), BT group and CBA group (13.41 ± 4.40 μm and 4.81 ± 4.44 μm, respectively) had significantly decreased ASM thickness after 1 month (P < 0.001). Furthermore, the ASM thickness was significantly lower in the 1-month post-CBA group than in the 1-month post-BT group (P = 0.015). There was no significant difference in ASM thickness between the BT and CBA groups after six months (9.92 ± 4.42 μm vs. 7.41 ± 7.20 μm, P = 0.540). Compared with the control group (0.161 ± 0.013), the average optical density of the ASM M3 receptor was significantly decreased in 6-month post-BT, 1-month post-CBA, and 6-month post-CBA groups (0.070 ± 0.022, 0.072 ± 0.012, 0.074 ± 0.008, respectively; all P < 0.001). There was no significant difference in the average optical density of ASM M3 receptor between the BT and CBA therapy groups after six months (P = 0.613).ConclusionsCBA therapy effectively ablates the ASM, and its ablation effect is equivalent to that of BT with a shorter onset time. A neural mechanism is involved in both BT and CBA therapy.

Project description:BackgroundBronchial thermoplasty (BT) is a bronchoscopic treatment for severe asthma, of which the working mechanism and responder profile are partly unknown. The aim of this study is to analyse whether BT alters airway inflammation by epithelial gene expression, inflammatory cell counts and cytokines, and whether this relates to treatment response.MethodsIn this clinical trial, 28 severe asthma patients underwent bronchoscopy before and after treatment to obtain bronchial brushes and bronchoalveolar lavage fluid (BALF) from treated and untreated airways. RNA was extracted from bronchial brushes for transcriptome analysis, and BALF cells and cytokines were analysed. Asthma quality of life questionnaires were used to distinguish responders from non-responders. We compared results before and after treatment, between treated and untreated airways, and between responders and non-responders.ResultsGene expression of airway epithelium related to airway inflammation gene set was significantly downregulated in treated airways compared to untreated airways, although this did not differ for patients before and after treatment. No differences were observed in cell counts and cytokines, neither from the untreated compared to treated airways, nor before and after treatment. At baseline, compared to non-responders, the expression of genes related to glycolysis in bronchial epithelium was downregulated and both BALF and blood eosinophil counts were higher in responders.ConclusionLocal differences in gene sets pertaining to epithelial inflammatory status were identified between treated and untreated airways after treatment, not resulting in changes in differential cell counts and cytokine analyses in BALF. Secondly, baseline epithelial glycolysis genes and eosinophil counts in BALF and blood were different between responders and non-responders. The observations from this study demonstrate the potential impact of BT on epithelial gene expression related to airway inflammation while also identifying a possible responder profile.

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Knowledge gaps in the field of bronchial thermoplasty.

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Knowledge gaps in the field of bronchial thermoplasty.

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