Bronchial Thermoplasty In Severe Asthma Research Articles

Airway wall extracellular matrix changes induced by bronchial thermoplasty in severe asthma

Airway remodeling is a prominent feature of asthma, including increased airway smooth muscle (ASM) mass and altered extracellular matrix (ECM) composition. Bronchial thermoplasty (BT), a bronchoscopic treatment for severe asthma, targets this airway remodeling. To investigate the effect of BT on ECM composition and its association with clinical outcomes. This is a sub-study of the TASMA trial. Thirty severe asthma patients were BT treated, of which 13 patients prior to BT were treated by six months of standard therapy (control group). Demographic data, clinical data including pulmonary function and bronchial biopsies were collected. Biopsies at BT treated and non-treated locations were analyzed by histological and immune-histochemical staining. Associations between histology and clinical outcomes were explored. Six months after treatment, reticular basement membrane (RBM) thickness was reduced from 7.28μm to 5.74μm (21% relative reduction) and the percentage area of tissue positive for collagen increased from 26.3% to 29.8% (13% relative increase). Collagen structure analysis revealed a reduction in the curvature frequency of fibers. The percentage area positive for fibulin-1 and fibronectin increased with 2.5% and 5.9% respectively (relative increase of 124% and 15%). No changes were found for elastin. The changes in collagen and fibulin-1 negatively associated with changes in FEV1-reversibility. Next to ASM reduction, BT impacts RBM thickness and the ECM arrangement characterized by an increase in tissue area occupied by collagen with a less dense fiber organization. Both collagen and fibulin-1 are negatively associated with the change in FEV1-reversibility. BT induces ECM reorganization and airway wall stability.

Bronchoalveolar lavage fluid cytokines and chemokines changes after bronchial thermoplasty in severe asthma.

Bronchial thermoplasty (BT) is a non-pharmacological intervention in severe asthma with a well-known mechanism of reducing airway smooth muscle. However, its effect on airway inflammation remains uncertain. To investigate the effect of BT on bronchoalveolar lavage fluid (BALF) cytokines and chemokines in severe asthma patients before BT, after the first BT, and 12 weeks after BT. Ten severe asthma patients were recruited, and BALF was obtained from right lower lobe before BT, after the first BT, and 12 weeks after BT. BALF analytes were measured and values were compared among the time points. Lung function, asthma control test (ACT), and asthma quality of life questionnaire (AQLQ) were also measured. Tumor necrosis factor (TNF)-α concentration was significantly decreased after the first BT and significantly increased at 12 weeks after BT. Interleukin-6 (IL-6) and TNF-related apoptosis inducing ligand (TRAIL) concentration were significantly increased at 12 weeks after BT. There were no significant changes in Regulated upon activation, normal T-cell expressed and secreted (RANTES) and transforming growth factor-beta1 (TGF-β1) concentration over time after BT. At 12 weeks after BT, there were significantly greater improvements in the scores on AQLQ (3.93 ± 0.88 to 5.3 ± 0.99, p = 0.002) and ACT (13.6 ± 3.27 to 19 ± 4.44, p = 0.002). The lung function did not differ significantly between pre- and post-BT. BT has limited effect on TNF-α, IL-6, TRAIL, RANTES, and TGF- β1 in BALF suggesting that its clinical benefit is not primarily related to this local airway inflammation. The effect on long-term airway inflammation probably needs further studies.

Airway Inflammation Before and After Bronchial Thermoplasty in Severe Asthma.

Bronchial 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. In 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. Gene 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. Local 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.

Cost Utility of Bronchial Thermoplasty for Severe Asthma: Implications for Future Cost-Effectiveness Analyses Based on Phenotypic Heterogeneity.

BackgroundAsthma is a disease with tremendous phenotypic heterogeneity, and the patients who are most severely impacted by the disease are high utilizers of the United States healthcare system. In the past decade, there has been many advances in asthma therapy for those with severe disease, including the use of a procedure called bronchial thermoplasty (BT) and the use of biologic therapy for certain phenotypes, but questions remain regarding the long-term durability and cost effectiveness of these therapies. The purpose of this analysis was (1) to assess the cost utility of BT relative to usual care (base case) and (2) to assess the cost utility of BT relative to usual care plus biologic therapy (omalizumab) (scenario analysis) based on updated 10-year clinical trial outcomes.MethodsA Markov cohort model was developed and used to estimate the cost utility of BT to estimate the costs and quality-of-life impact of BT versus the comparisons over a 10-year time frame using a limited societal perspective, which included both direct health utilization costs and indirect costs associated with missed days of work, among those with severe persistent asthma.ResultsIn the base case and the scenario analysis, BT was the dominant treatment strategy compared to usual care alone and usual care plus biologic therapy. The net monetary benefit for BT was $483,555.49 over a 10-year time horizon.ConclusionCost-utility models are central to policy decisions dictating coverage, and can be extended to inform the patient and provider, during clinical decision-making, of the relative trade-offs of therapy, assessing long-term clinical and cost outcomes. Phenotypic classification of severe asthma is central to patient management and should also be integrated into economic analysis frameworks, particularly as new biologic agents are developed that are specific to a phenotype. Despite a larger upfront cost of BT therapy, there is a durable clinical and economic benefit over time for those with severe asthma.

Bronchial thermoplasty in severe asthma: a real-world study on efficacy and gene profiling

BackgroundBronchial thermoplasty (BT) is an effective treatment in severe asthma. How to select patients who more likely benefit from BT is an unmet clinical need. Moreover, mechanisms of BT efficacy are still largely unknown. We sought to determine BT efficacy and to identify potential mechanisms of response.MethodsThis retrospective cohort study evaluated clinical outcomes in 27 patients with severe asthma: 13 with T2-high and 14 with T2-low endotype. Expression levels of 20 genes were compared by real-time PCR in bronchial biopsies performed at the third BT session versus baseline. Clinical response was measured based on Asthma Control Questionnaire (ACQ) score < 1.5, asthma exacerbations < 2, oral corticosteroids reduction of at least 50% at 12 months post-BT. Patients were classified as responders when they had at least 2 of 3 outcome measures.Results81% of patients were defined as responders. BT induced a reduction in alpha smooth muscle actin (ACTA2) and an increase in CD68, fibroblast activation protein-alpha (FAP), alpha-1 and alpha-2 type I collagen (COL1A1, COL1A2) gene expression in the majority of patients. A higher reduction in ubiquitin carboxy-terminal-hydrolase L1 (PGP9.5) mRNA correlated with a better response based on Asthma Quality of Life Questionnaire (AQLQ). Lower changes in CD68 and FAP mRNAs correlated with a better response based on ACQ. Lower levels of occludin (OCLN), CD68, connective tissue growth factor (CTGF), higher levels of secretory leukocyte protease inhibitor (SLPI) and lower changes in CD68 and CTGF mRNAs were observed in patients who had less than 2 exacerbations post-BT. Lower levels of COL1A2 at baseline were observed in patients who had ACQ < 1.5 at 12 months post-BT.ConclusionsBT is effective irrespective of the asthma endotypes and seems associated with airway remodelling. Quantification of OCLN, CD68, CTGF, SLPI, COL1A2 mRNAs could be useful to identify patients with better results.Trial registration: The study protocol was approved by the Local Ethics Committee (Azienda USL-IRCCS of Reggio Emilia—Comitato Etico Area Vasta Nord of Emilia Romagna; protocol number: 2019/0014076) and all the patients provided written informed consent before participating in the study.

Recent advances in bronchial thermoplasty for severe asthma: a narrative review

Background and ObjectiveSevere asthma refers to asthma that requires step 4 or 5 therapy recommended by Global Initiative for Asthma (GINA) to prevent it from becoming uncontrolled or remaining “uncontrolled” despite this therapy. The poor treatment effect of severe asthma has been perplexing clinicians, which reduces the quality of life (QoL) of patients with asthma, and increases the mortality of such patients, so improving the therapeutic effect of severe asthma is an urgent problem to be solved in the clinic. Bronchial thermoplasty (BT) is a new non-drug therapy for severe asthma that is difficult to control with medications. It has been approved for clinical practice in China and the United States. The article aims at providing a new treatment option for patients with severe asthma that is poorly controlled by medications, thus improving the QoL in these patients.MethodsAn extensive literature search was performed in the PubMed database, with “bronchial thermoplasty” as the key term. The full texts of all potentially relevant articles were obtained, and relevant information was extracted.Key Content and FindingsWe find that BT is suitable for patients with severe asthma poorly controlled by medications.ConclusionsThis paper reviews the mechanism of action, procedure, safety and effectiveness, adverse effects and complications, problems, and prospects of BT, with an attempt to guide the practical application of this technique.

Use of Health Related Quality of Life in Clinical Trials for Severe Asthma: A Systematic Review.

BackgroundAsthma Health Related Quality of Life (HRQoL) is an outcome important to patients with severe asthma and can provide clinicians with additional insight into the benefits of treatment. The aim of this systematic review is to examine the use and reporting of HRQoL questionnaires within randomised controlled trials (RCTs) of biologics, fevipiprant and bronchial thermoplasty.MethodsWe followed the guidelines on the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) statement. Of the 2380 retrieved articles, 52 studies were identified for inclusion.ResultsSixty-three percent included an asthma HRQoL questionnaire. It was a secondary outcome in the majority of cases (73%). The proportion of studies including an asthma HRQoL questionnaire did not change significantly over a 20-year period. While the Asthma Quality of Life Questionnaire (AQLQ) was used in 45% of studies, 55% used a variety of 4 questionnaires. Most (70%) of the studies that included a HRQoL questionnaire did not report its subscale scores. Approximately half (52%) of studies that used HRQoL reported this in the abstract of the paper. A higher proportion of studies used an asthma control questionnaire compared to a HRQoL questionnaire (71% vs 63%).ConclusionIn order to increase the use of asthma HRQoL questionnaires in RCTs of severe asthma treatments, the drivers and barriers to their use must first be understood. At present, the patients’ perspective is underrepresented in RCTs of biologics, fevipiprant and bronchial thermoplasty for severe asthma.

Bronchial Thermoplasty for Severe Asthma: From Past to Present and Future

Background: Approximately 3-10% of all asthmatics are refractory with severe disease, although they use optimal preventive treatment. This is reflected as a disproportionate increase in the cost of health care. Thus, bronchial thermoplasty has been developed as an add-on therapy for these refractory asthmatics. Objective: This review aims to give an update on bronchial thermoplasty in severe asthma regarding pathophysiological mechanisms of action, patient selection, procedural details, history, evidence- based effectiveness, safety and cost-effectiveness, place in management, and challenges in current clinical practice. Methods: A thorough search for the eligible and recent studies and reviews on bronchial thermoplasty and asthma has been conducted in PubMed. Results: In bronchial thermoplasty, radiofrequency energy delivered to bronchial airway walls leads to ablation of the airway smooth muscles that cause bronchoconstriction. Several large trials and a real-world study confirm its safety, and effectiveness, as shown by considerable reduction in asthma exacerbations, emergency department visits and hospitalizations as well as improvement in asthma-related quality of life, maintained up to 5 years. These improvements are more significant in more severe airway obstruction. Bronchial thermoplasty is more cost-effective if hospitalization and emergency department care cost high, but the procedure costs low. Properly performed patient identification, implementation and follow-up are critical for successful and safe outcomes with the procedure. Conclusion: A 10-year research and clinical experience has proved the long-term safety, and effectiveness of bronchial thermoplasty for improving asthma control and quality of life in severe asthma. Predictors of response (e.g. biomarkers, responder endotype/phenotype) remain to be studied further and better qualified.

Analysis of the safety and efficacy of bronchial thermoplasty for severe asthma with the first second forced expiratory volume (FEV(1)) as a percentage of the predicted value (FEV(1)%pred)

Objective: To investigate the efficacy and safety of bronchial thermoplasty (BT) in severe asthma patients with the first second forced expiratory volume (FEV(1)) as a percentage of the predicted value (FEV(1)%pred) <60%. Methods: A retrospective analysis was performed on 75 patients with asthma who were treated with BT at Shenzhen University Hospital of the Chinese Academy of Sciences from January 2016 to January 2018. The patients were divided into two groups based on the FEV(1)%pred before treatment: FEV(1)%pred <60% group (39 cases) and FEV(1)%pred ≥60% group (36 cases). Comparative analysis of glucocorticoid consumption, times of acute attack, asthma control test (ACT) score, changes in lung function, and adverse reactions at 3 weeks after treatment were performed between the two groups of patients. Results: Before BT treatment, the consumption of oral prednisone, the amount of budesonide inhaled, and the times of acute attack [M (Q(1), Q(3))] in the FEV(1)%pred <60% group were significantly greater than those in the FEV(1)%pred ≥60% group, and the ACT score was significantly lower than the FEV(1)%pred ≥60% group [10.00 (0, 20.00) vs 0(0, 3.75) mg/d, 960 (320, 960) vs 320 (320, 640) μg/d, 5(4, 8) vs 4 (4, 5) times/year, 13 (9, 15) vs 17 (13, 19) scores] (all P<0.05). Except that the oral prednisone dosage in the FEV(1)%pred<60% group was still higher 1 year after treatment [0 (0, 5.00) vs 0 (0, 0) mg/d] (P=0.009), there was no significant difference in the remaining indicators between the two groups 1 year after treatment and 2 years after treatment (all P>0.05). After 1 year and 2 years of treatment, all indicators in the two groups were better than before treatment (all P<0.05). The inhaled budesonide amount and the times of acute exacerbation in the FEV(1)%pred <60% group 2 years after treatment were less than those 1 year after treatment [320 (320, 320) vs 320 (320, 640) μg/d, 0 (0, 0) vs 0(0, 1) times/year] (all P<0.05), and there was no significant difference in the remaining indicators. In the FEV(1)%pred ≥60% group, there was no significant difference between 2 years after treatment and 1 year after treatment in the above indicators except the amount of inhaled budesonide (all P>0.05). In the FEV(1)%pred <60% group, FEV(1) and the FEV(1)%pred were significantly lower than the FEV(1)%pred ≥60% group before treatment, 1 year after treatment and 2 years after treatment [FEV(1):(1.21±0.41) vs (2.26±0.80)L, (1.84±0.73) vs (2.30±0.78)L, (1.70±0.66) vs (2.38±0.76)L; FEV(1)%pred:46.2 (38.5, 53.7)% vs 80.8(66.5, 93.6)%, 60.1 (48.2, 71.6)% vs 87.4 (68.5, 96.5)%, 58.5 (48.6, 74.8)% vs 86.6 (73.0, 97.3)%] (all P<0.05). In the FEV(1)%pred <60% group, FEV(1) and FEV(1)%pred 1 year after treatment and 2 years after treatment were all increased compared with before treatment (all P<0.05). In the FEV(1)%pred ≥60% group, there was no statistical difference in FEV(1) at each time point before and after treatment (all P>0.05), but the FEV(1)%pred at 2 years after treatment was higher than before treatment (P<0.05). There were no significant differences in adverse events between the two groups (all P>0.05). Conclusion: BT can significantly improve the lung function, reduce the times of acute attack and the dosage of glucocorticoids in severe asthma patients with FEV(1)% pred<60%, which is safe and effective.

Bronchial thermoplasty for severe asthma: A position statement of the Indian chest society.

Bronchial thermoplasty (BT) is an interventional bronchoscopic treatment for severe asthma. There is a need to define patient selection criteria to guide clinicians in offering the appropriate treatment options to patients with severe asthma. Methodology: An expert group formed this statement under the aegis of the Indian Chest Society. We performed a systematic search of the MEDLINE and EMBASE databases to extract evidence on patient selection and the technical performance of BT. Results: The experts agreed that the appropriate selection of patients is crucial and proposed identification of the asthma phenotype, a screening algorithm, and inclusion/exclusion criteria for BT. In the presence of atypical clinical or chest radiograph features, there should be a low threshold for obtaining a thoracic computed tomography scan before BT. The patient should not have had an asthma exacerbation in the preceding two weeks from the day of the procedure. A 5-day course of glucocorticoid should be administered, beginning three days before the procedure day, and continued until the day following the procedure. General Anesthesia (total intravenous anesthesia with a neuromuscular blocker) provides ideal conditions for performing BT. A thin bronchoscope with a 2.0 mm working channel is preferable. An attempt should be made to deliver the maximum radiofrequency activations. Middle lobe treatment is not recommended. Following the procedure, overnight observation in the hospital, and a follow-up visit, a week following each treatment session, is desirable. Conclusion: This position statement provides practical guidance regarding patient selection and the technical performance of BT for severe asthma.

Interventionen beim Asthma COPD

Advanced emphysema and asthma constitute major health burden worldwide and are associated with significant morbidity and mortality. Pharmacological options are limited. Researches are being carried out aiming to modify the natural course of both the diseases. Lung volume reduction surgeries are performed in advanced emphysema but are associated with significant morbidity and prolonged hospital stay. Various minimally invasive bronchoscopic methods have been developed with the goal of achieving clinical benefits of volume reduction surgery but lower complications. Bronchial thermoplasty is a bronchoscopic method of delivering controlled heat in the airways to reduce airway smooth muscle mass, thereby reducing bronchoconstriction in patients with severe asthma who remain uncontrolled despite optimal medical therapy. Various randomised controlled trials have been performed to evaluate the safety and efficacy of various endoscopic treatments like valves, coils, use of sclerosants and targeted lung denervation for severe emphysema and bronchial thermoplasty in severe asthma. The current review summaries the clinical trial evidence available for lung volume reduction in emphysema and thermoplasty in asthma and provide guidance for optimal patient selection for various therapies available.

Recent Developments In Bronchial Thermoplasty For Severe Asthma.

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.

Persistent Reduction of Mucin Production after Bronchial Thermoplasty in Severe Asthma.

Persistent Reduction of Mucin Production after Bronchial Thermoplasty in Severe Asthma.

Effectiveness and Safety of Bronchial Thermoplasty in Severe Asthma in Clinical Practice in Spain

Background: Bronchial thermoplasty (BT) is a minimally invasive procedure consisting of application of thermal energy into the airways to produce ablation of the hypertrophic smooth muscle. It was approved for use in moderate-severe asthma in Spain in 2010. Objectives: The aims of the present study are to analyze the effectiveness and the safety of BT in clinical practice in our center. Methods: Participants had a confirmed diagnosis of severe asthma and poor control without therapeutic alternative. Effectiveness was measured by comparing exacerbations, admissions rates, asthma control, and medication 1 year prior and 1 year after BT was completed. All complications appearing during the procedure and in the first year were recorded. Results: Patients had a mean age of 51 (SD 8) years and were predominantly female (17/23). The average number of activations per patient was 147 (16). The number of severe exacerbations was reduced by 75% (p < 0.001). A 38% reduction in admissions per year was also observed (p = 0.03). The Asthma Control Test improved by 7.1 (3.7) points (p = 0.018). Before BT, the dose of inhaled corticosteroids was 1,621 (1,015) µg of budesonide-equivalent and the dose of oral corticosteroids was 15 (13) mg of prednisone-equivalent. There was a reduction in 430 (731) µg of budesonide-equivalent (p = 0.02) and 4 (11) mg of prednisone (p = 0.094). No changes in lung function were observed. Complications were related mostly to exacerbation of asthma in the days following the procedure. Conclusions: BT is effective and safe for severe uncontrolled bronchial asthma in real clinical practice.

Quantitative CT detects changes in airway dimensions and air-trapping after bronchial thermoplasty for severe asthma

ObjectivesBronchial thermoplasty (BT) can be considered in the treatment of severe asthma to reduce airway smooth muscle mass and bronchoconstriction. We hypothesized that BT may thus have long-term effects on airway dimensions and air-trapping detectable by quantitative computed tomography (QCT). MethodsPaired in- and expiratory CT and inspiratory CT were acquired in 17 patients with severe asthma before and up to two years after bronchial thermoplasty and in 11 additional conservatively treated patients with serve asthma, respectively. A fully automatic software calculated the airways metrics for wall thickness (WT), wall percentage (WP), lumen area (LA) and total diameter (TD). Furthermore, lung air-trapping was quantified by determining the quotient of mean lung attenuation in expiration vs. inspiration (E/I MLA) and relative volume change in the Hounsfield interval −950 to −856 in expiration to inspiration (RVC856-950) in a generation- and lobe-based approach, respectively. ResultsBT reduced WT for the combined analysis of the 2nd–7th airway generation significantly by 0.06 mm (p = 0.026) and WP by 2.05% (p < 0.001), whereas LA and TD did not change significantly (p = 0.147, p = 0.706). No significant changes were found in the control group. Furthermore, E/I MLA and RVC856-950 decreased significantly after BT by 12.65% and 1.77% (p < 0.001), respectively. ConclusionBT significantly reduced airway narrowing and air-trapping in patients with severe asthma. This can be interpreted as direct therapeutic effects caused by a reduction in airway-smooth muscle mass and changes in innervation. A reduction in air-trapping indicates an influence on more peripheral airways not directly treated by the BT procedure.

Bronchial thermoplasty for asthma treatment

New asthma therapies such as omalizumab, mepolizumab and reslizumab are used according to the inflammatory phenotype, but there are many patients with asthma which are not suitable for these therapies or do not improve with these therapies. Bronchial thermoplasty (BT) was approved by FDA for the treatmet of adults with severe asthma and uncontrolled symptoms despite treatment with inhaler corticosteroids (ICS) and long-acting bronchodilators in 2010. BT is a minimally invasive bronhoscopic intervention based on radiofrequency energy delivery to the larger airways to reduce excessive airway smooth muscle mass. BT has been shown to be effective at reducing asthma exacerbations and improving asthma control for patients with severe asthma. BT is safe for 5 years after BT in patients with severe refractory asthma. BT may be primarily preferred for patients with nonallergic, non-eosinophilic (non-TH2) severe asthma not improving with standart treatments. Unfortunately, the mechanism of action of BT is incompletely understood. Uncertainty remains how to identify patients who will responde to this intervention. Several studies are underway that may show the place of BT in severe asthma and identify responders. There is also a need for studies comparing BT with other treatment options. This review will provide an overwiew of BT. We will discuss the latest evidence on the use of BT in asthma, patient selection criteria and performing the procedure will be reviewed.

Bronchial Thermoplasty in Severe Asthma

Bronchial thermoplasty (BT) is an endoscopic treatment for severe and uncontrolled asthma. This review provides an overview of the indications, selection criteria, treatment application, and scientific evidence regarding its mechanism of action and safety and efficacy of BT in current clinical practice. It seems that reduction in airway smooth muscle is one of the principal mechanisms of action, since it correlates with clinical benefits. Regarding safety and efficacy, recent case reports and small prospective studies appear to show benefit in more severe asthma patients. Further research is needed to better understand the physiological benefits of BT and select the best candidates for treatment. In order to achieve these goals, experts recommend performing BT only in specialized centers.

Bronchial thermoplasty in severe asthma in Australia.

Bronchial thermoplasty (BT) is an approved bronchoscopic intervention for the treatment of severe asthma. However, limited published experience exists outside of clinical trials regarding patient selection and outcomes achieved. To evaluate the effectiveness and safety of BT in patients with severe asthma encountered in clinical practice. This is a retrospective analysis of the first 'real world' data from Australia. The following outcomes were measured prior to, and 6 months following BT: spirometry, Asthma Control Questionnaire-5 (ACQ-5) score, reliever and preventer medication use and exacerbation history. Twenty patients were treated from June 2014 to December 2015 at three university teaching hospitals. All subjects met the European Respiratory Society/American Thoracic Society definition of severe asthma. Mean pre-bronchodilator forced expiratory volume in 1 s was 62.8 ± 16.6% predicted (range: 33-95%). All patients were being treated with high dose inhaled corticosteroids, long-acting beta2 agonists and long-acting muscarinic antagonists. Ten patients (50%) were taking maintenance oral prednisolone. Most subjects also required at least one of montelukast (65%), omalizumab (30%) and methotrexate (20%). ACQ-5 improved from 3.6 ± 1.1 at baseline to 1.6 ± 1.2 at 6 months, P < 0.001. Short-acting reliever use decreased from a median of 8.0-0.25 puffs/day, P < 0.001, and exacerbations requiring corticosteroids also significantly reduced. Five of 10 patients completely discontinued maintenance oral corticosteroids. Ten patients with a baseline forced expiratory volume in 1 s of <60% predicted significantly improved from 49.2 ± 9.6% to 61.8 ± 17.6%, P < 0.05. Only two procedures required hospitalisation beyond the planned overnight admission. BT is a safe procedure which can achieve clinical improvement in those with uncontrolled symptoms and severe airflow obstruction.

Bronchial thermoplasty in asthma: Scrutinizing the current evidence

Objectives: Severe asthma accounts for 5-10% of all asthma cases and half of asthma-related costs in developed countries. Targeting smooth muscle hypertrophy and hyperplasia using bronchial thermoplasty (BT) represents a novel therapeutic approach to this disease. This review aims to critically examine and appraise the methodology and interpretation of individual clinical trials concerning the use of BT in severe asthma. It is not intended to be a systematic review or a meta-analysis. Methods: PubMed, Ovid MEDLINE, Ovid EMBASE, Google Scholar, and Scopus were searched until August, 31st 2015 for published clinical trials concerning the use of BT in asthma patients. Search titles included BT, severe asthma, BT in asthma, BT and severe asthma and effectiveness and safety of BT in asthma. Results: One published non-randomized, three randomized and three extension trials were identified. The methodology and results of each individual trial were subjected to careful examination and appraisal. A good safety profile of BT as a novel therapeutic approach of severe asthma has been confirmed in multiple clinical trials. However, there are still unanswered questions and concerns regarding the effectiveness of this procedure in severe asthma. The evidence concerning this effectiveness needs to be augmented by further well-designed sham controlled trials. Conclusion: Well-designed controlled trials using hard outcome measures such as asthma control, lung function and ability to withdraw/reduce steroid are desperately needed to confirm the effectiveness of BT in severe asthma cases. Consideration of asthma phenotypes when conducting such trials would be rewarding.

Indications for the use of bronchial thermoplasty in severe asthma.

Approximately 5% of the ~3 million asthmatics in South Africa have severe asthma that is associated with substantial morbidity, cost, absenteeism, preventable mortality, and the requirement for costly chronic medication that may be associated with significant adverse events. There is an unmet need for alternative safer and more effective interventions for severe asthma. A recently introduced option, bronchial thermoplasty (BT), imparts radiofrequency-generated heat energy to the airways to cause regression of airway smooth muscle. The effectiveness of this technique has been confirmed in randomised control trials and is now endorsed by several international guidelines, including the Global Initiative for Asthma (GINA) guideline, the British Asthma Guideline, and the UK National Institute of Clinical Excellence (NICE) guideline. We recommend BT as a potential therapeutic intervention for severe uncontrolled asthma, provided that it is performed by an experienced pulmonologist at an accredited centre and done within the broader context of appropriate management of the disease by doctors experienced in treating difficult-to-control asthma.