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Foo CT, Donovan GM, Thien F, Langton D, Noble PB. Bronchial Thermoplasty Improves Ventilation Heterogeneity Measured by Functional Respiratory Imaging in Severe Asthma. J Asthma Allergy 2024; 17:399-409. [PMID: 38681236 PMCID: PMC11048211 DOI: 10.2147/jaa.s454951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/22/2024] [Indexed: 05/01/2024] Open
Abstract
Purpose Bronchial thermoplasty (BT) is a bronchoscopic intervention for the treatment of severe asthma. Despite demonstrated symptomatic benefit, the underlying mechanisms by which this is achieved remain uncertain. We hypothesize that the effects of BT are driven by improvements in ventilation heterogeneity as assessed using functional respiratory imaging (FRI). Patient and Methods Eighteen consecutive patients with severe asthma who underwent clinically indicated BT were recruited. Patients were assessed at baseline, 4-week after treatment of the left lung, and 12-month after treatment of the right lung. Data collected included short-acting beta-agonist (SABA) and oral prednisolone (OCS) use, asthma control questionnaire (ACQ-5) and exacerbation history. Patients also underwent lung function tests and chest computed tomography. Ventilation parameters including interquartile distance (IQD; measure of ventilation heterogeneity) were derived using FRI. Results 12 months after BT, significant improvements were seen in SABA and OCS use, ACQ-5, and number of OCS-requiring exacerbations. Apart from pre-bronchodilator FEV1, no other significant changes were observed in lung function. Ventilation heterogeneity significantly improved after treatment of the left lung (0.18 ± 0.04 vs 0.20 ± 0.04, p=0.045), with treatment effect persisting up to 12 months later (0.18 ± 0.05 vs 0.20 ± 0.04, p=0.028). Ventilation heterogeneity also improved after treatment of the right lung, although this did not reach statistical significance (0.18 ± 0.05 vs 0.19 ± 0.04, p=0.06). Conclusion Clinical benefits after BT are accompanied by improvements in ventilation heterogeneity, advancing our understanding of its mechanism of action. Beyond BT, FRI has the potential to be expanded into other clinical applications.
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Affiliation(s)
- Chuan T Foo
- Department of Respiratory Medicine, Eastern Health, Melbourne, VIC, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Francis Thien
- Department of Respiratory Medicine, Eastern Health, Melbourne, VIC, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
| | - David Langton
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
- Department of Thoracic Medicine, Peninsula Health, Frankston, VIC, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
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2
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Hatch M, Lilburn P, Scott C, Ing A, Langton D. Safety and efficacy of bronchial thermoplasty in Australia 5 years post-procedure. Respirology 2023; 28:1053-1059. [PMID: 37550800 DOI: 10.1111/resp.14568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/17/2023] [Indexed: 08/09/2023]
Abstract
BACKGROUND AND OBJECTIVE Outside clinical trials, there is limited long-term data following bronchial thermoplasty (BT). In a cohort of real-world severe asthmatics in an era of biological therapy, we sought to evaluate the safety and efficacy of BT 5 years post-treatment. METHODS Every patient treated with BT at two Australian tertiary centres were recalled at 5 years, and evaluated by interview and record review, Asthma Control Questionnaire (ACQ), spirometry and high-resolution CT Chest. CT scans were interpreted using the modified Reiff and BRICS CT scoring systems for bronchiectasis. RESULTS Fifty-one patients were evaluated. At baseline, this cohort had a mean age of 59.0 ± 11.8 years, mean ACQ of 3.0 ± 1.0, mean FEV1 of 55.5 ± 18.8% predicted, and 53% were receiving maintenance oral steroids in addition to triple inhaler therapy. At 5 years, there was a sustained improvement in ACQ scores to 1.8 ± 1.0 (p < 0.001). Steroid requiring exacerbation frequency was reduced from 3.8 ± 3.6 to 1.0 ± 1.6 exacerbations per annum (p < 0.001). 44% of patients had been weaned off oral steroids. No change in spirometry was observed. CT scanning identified minor degrees of localized radiological bronchiectasis in 23/47 patients with the modified Reiff score increasing from 0.6 ± 2.6 at baseline to 1.3 ± 2.5 (p < 0.001). However, no patients exhibited clinical features of bronchiectasis, such as recurrent bacterial infection. CONCLUSION Sustained clinical benefit from BT at 5 years was demonstrated in this cohort of very severe asthmatics. Mild, localized radiological bronchiectasis was identified in a portion of patients without clinical features of bronchiectasis.
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Affiliation(s)
- Monica Hatch
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, Frankston, Victoria, Australia
| | - Paul Lilburn
- Department of Respiratory and Sleep Medicine, Prince of Wales Hospital, Sydney, New South Wales, Australia
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Caroline Scott
- Radiology Department, Frankston Hospital, Peninsula Health, Frankston, Victoria, Australia
| | - Alvin Ing
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - David Langton
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, Frankston, Victoria, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
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3
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Liao X, Gao S, Xie F, Wang K, Wu X, Wu Y, Gao W, Wang M, Sun J, Liu D, Xu W, Li Q. An underlying mechanism behind interventional pulmonology techniques for refractory asthma treatment: Neuro-immunity crosstalk. Heliyon 2023; 9:e20797. [PMID: 37867902 PMCID: PMC10585236 DOI: 10.1016/j.heliyon.2023.e20797] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 09/11/2023] [Accepted: 10/06/2023] [Indexed: 10/24/2023] Open
Abstract
Asthma is a common disease that seriously threatens public health. With significant developments in bronchoscopy, different interventional pulmonology techniques for refractory asthma treatment have been developed. These technologies achieve therapeutic purposes by targeting diverse aspects of asthma pathophysiology. However, even though these newer techniques have shown appreciable clinical effects, their differences in mechanisms and mutual commonalities still deserve to be carefully explored. Therefore, in this review, we summarized the potential mechanisms of bronchial thermoplasty, targeted lung denervation, and cryoablation, and analyzed the relationship between these different methods. Based on available evidence, we speculated that the main pathway of chronic airway inflammation and other pathophysiologic processes in asthma is sensory nerve-related neurotransmitter release that forms a "neuro-immunity crosstalk" and amplifies airway neurogenic inflammation. The mechanism of completely blocking neuro-immunity crosstalk through dual-ablation of both efferent and afferent fibers may have a leading role in the clinical efficacy of interventional pulmonology in the treatment of asthma and deserves further investigation.
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Affiliation(s)
- Ximing Liao
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Shaoyong Gao
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Fengyang Xie
- Department of Hematology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Kun Wang
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaodong Wu
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yin Wu
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wei Gao
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Muyun Wang
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jiaxing Sun
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Dongchen Liu
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, China
| | - Wujian Xu
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qiang Li
- Department of Respiratory and Critical Care Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
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4
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Wang CJ, Noble PB, Elliot JG, James AL, Wang KCW. From Beneath the Skin to the Airway Wall: Understanding the Pathological Role of Adipose Tissue in Comorbid Asthma-Obesity. Compr Physiol 2023; 13:4321-4353. [PMID: 36715283 DOI: 10.1002/cphy.c220011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This article provides a contemporary report on the role of adipose tissue in respiratory dysfunction. Adipose tissue is distributed throughout the body, accumulating beneath the skin (subcutaneous), around organs (visceral), and importantly in the context of respiratory disease, has recently been shown to accumulate within the airway wall: "airway-associated adipose tissue." Excessive adipose tissue deposition compromises respiratory function and increases the severity of diseases such as asthma. The mechanisms of respiratory impairment are inflammatory, structural, and mechanical in nature, vary depending on the anatomical site of deposition and adipose tissue subtype, and likely contribute to different phenotypes of comorbid asthma-obesity. An understanding of adipose tissue-driven pathophysiology provides an opportunity for diagnostic advancement and patient-specific treatment. As an exemplar, the potential impact of airway-associated adipose tissue is highlighted, and how this may change the management of a patient with asthma who is also obese. © 2023 American Physiological Society. Compr Physiol 13:4321-4353, 2023.
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Affiliation(s)
- Carolyn J Wang
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - John G Elliot
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia.,Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Alan L James
- Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Medical School, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia.,Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
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5
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Hsieh A, Assadinia N, Hackett TL. Airway remodeling heterogeneity in asthma and its relationship to disease outcomes. Front Physiol 2023; 14:1113100. [PMID: 36744026 PMCID: PMC9892557 DOI: 10.3389/fphys.2023.1113100] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
Asthma affects an estimated 262 million people worldwide and caused over 461,000 deaths in 2019. The disease is characterized by chronic airway inflammation, reversible bronchoconstriction, and airway remodeling. Longitudinal studies have shown that current treatments for asthma (inhaled bronchodilators and corticosteroids) can reduce the frequency of exacerbations, but do not modify disease outcomes over time. Further, longitudinal studies in children to adulthood have shown that these treatments do not improve asthma severity or fixed airflow obstruction over time. In asthma, fixed airflow obstruction is caused by remodeling of the airway wall, but such airway remodeling also significantly contributes to airway closure during bronchoconstriction in acute asthmatic episodes. The goal of the current review is to understand what is known about the heterogeneity of airway remodeling in asthma and how this contributes to the disease process. We provide an overview of the existing knowledge on airway remodeling features observed in asthma, including loss of epithelial integrity, mucous cell metaplasia, extracellular matrix remodeling in both the airways and vessels, angiogenesis, and increased smooth muscle mass. While such studies have provided extensive knowledge on different aspects of airway remodeling, they have relied on biopsy sampling or pathological assessment of lungs from fatal asthma patients, which have limitations for understanding airway heterogeneity and the entire asthma syndrome. To further understand the heterogeneity of airway remodeling in asthma, we highlight the potential of in vivo imaging tools such as computed tomography and magnetic resonance imaging. Such volumetric imaging tools provide the opportunity to assess the heterogeneity of airway remodeling within the whole lung and have led to the novel identification of heterogenous gas trapping and mucus plugging as important predictors of patient outcomes. Lastly, we summarize the current knowledge of modification of airway remodeling with available asthma therapeutics to highlight the need for future studies that use in vivo imaging tools to assess airway remodeling outcomes.
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Affiliation(s)
- Aileen Hsieh
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Najmeh Assadinia
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Tillie-Louise Hackett
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada,*Correspondence: Tillie-Louise Hackett,
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6
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Li A, Lee P. Which Endoscopic Procedure to Use and in What Patient? Valves, Coils, Foam, and Heat in COPD and Asthma. Pulm Ther 2022; 9:49-69. [PMID: 36534323 PMCID: PMC9931990 DOI: 10.1007/s41030-022-00208-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/10/2022] [Indexed: 12/23/2022] Open
Abstract
Despite the latest developments in therapeutic agents targeting airway endotypes, a significant proportion of patients with asthma and chronic obstructive pulmonary disease (COPD) remain symptomatic. Endoscopic therapies have a complementary role in the management of these airway diseases. The sustained efficacy of bronchial thermoplasty (BT) among patients with asthma over 10 years has been encouraging, as it has been shown to improve symptom control and reduce hospital admissions and exacerbations. Studies suggest that BT helps ameliorate airway inflammation and reduce airway smooth muscle thickness. While studies suggest that it is as effective as biologic agents, its role in the management of severe asthma has yet to be clearly defined and GINA 2022 still suggests limiting its use to patients with characteristics of the various populations studied. Conversely, bronchoscopic lung volume reduction has shown promise among patients with advanced COPD. Rigorous patient selection is important. Patients with minimal collateral ventilation (CV) and higher heterogeneity index have shown to benefit the most from endobronchial valve (EBV) therapy. For those with ongoing CV, endobronchial coils would be more appropriate. Both therapeutic modalities have demonstrated improved quality of life, effort tolerance, and lung function indices among appropriately selected patients. The emerging evidence suggests that endoscopic procedures among airway disease still have a substantial role to play despite the development of new therapeutic options.
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Affiliation(s)
- Andrew Li
- Respiratory and Critical Care Medicine, National University Hospital, 1E Kent Ridge Road, Singapore, 119228, Singapore. .,Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,Respiratory Service, Department of Medicine, Woodlands Health, Singapore, Singapore.
| | - Pyng Lee
- Respiratory and Critical Care Medicine, National University Hospital, 1E Kent Ridge Road, Singapore, 119228 Singapore ,Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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7
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Donovan GM, Noble PB, Langton D. Therapeutic response to bronchial thermoplasty: toward feasibility of patient selection based on modeling predictions. J Appl Physiol (1985) 2022; 133:1341-1348. [PMID: 36356255 DOI: 10.1152/japplphysiol.00493.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bronchial thermoplasty (BT) is a treatment for moderate-to-severe asthma in which the airway smooth muscle layer is targeted directly using thermal ablation. Although it has been shown to be safe and effective in long-term follow-up, questions remain about its mechanism of action, patient selection, and optimization of protocol based on structural phenotype. Using a cohort of 20 subjects who underwent thermoplasty and assessment by computed tomography (CT), we demonstrate that response to BT can be feasibly predicted based on pretreatment airway dimensions that inform a subject-specific computational model. Analysis revealed the need for CT assessment at total lung capacity, rather than functional residual capacity, which was less sensitive to the effects of BT. Final model predictions compared favorably with observed outcomes in terms of airway caliber and asthma control, suggesting that this approach could form the basis of improved clinical practice.NEW & NOTEWORTHY Bronchial thermoplasty is a treatment for asthma that targets the airway smooth muscle directly. We demonstrate the feasibility and constraints of predicting patient-specific response to thermoplasty using a computational model informed by pretreatment CT scans at different lung volumes. Predictions are compared with functional outcomes and posttreatment CT scans. This has the potential to form the basis for improved clinical practice.
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Affiliation(s)
- G M Donovan
- Department of Mathematics, The University of Auckland, Auckland, New Zealand
| | - P B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - D Langton
- Faculty of Medicine, Nursing and Allied Health, Monash University, Melbourne, Victoria, Australia
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8
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Huang Y, Qiu C. Research advances in airway remodeling in asthma: a narrative review. ANNALS OF TRANSLATIONAL MEDICINE 2022; 10:1023. [PMID: 36267708 PMCID: PMC9577744 DOI: 10.21037/atm-22-2835] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/06/2022] [Indexed: 12/04/2022]
Abstract
Background and Objective Asthma is a common chronic disorder of the airway, and its disability and mortality rates continue to increase each year. Due to the lack of an ideal treatment, asthma control in China remains unsatisfactory. Airway remodeling is the pathological basis for the eventual development of the fixed airflow limitation in asthmatic patients. Early diagnosis and the prevention of airway remodeling has the potential to decrease disease severity, to improve control, and to prevent disease expression. Methods This article presents an overview. The literature was combed through via CNKi and PubMed according to the listed keywords. We considered Chinese and English original publications (basic science and clinical), reviews and abstracts of 21th Century. Key Content and Findings We review the pathological features and pathogenesis of, and the interventional treatment options for airway remodeling in asthmatic patients, emphasizing the importance of airway remodeling in asthma and providing novel insights into the prevention and control of asthma. Conclusions Thus, there have been research advances in airway remodeling, especially in the areas of slowing down or reversing airway remodeling. As growing studies showed, treating airway remodeling is a promising strategy in preventing the occurrence and progression of asthma. Breakthroughs in these difficulties airway remodeling still facing will open up new avenues in the research and treatment of asthma.
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Affiliation(s)
- Yanmei Huang
- Department of Respiratory and Critical Care Medicine, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Chen Qiu
- Department of Respiratory and Critical Care Medicine, Shenzhen People’s Hospital, Shenzhen, China
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9
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Hashmi MD, Khan A, Shafiq M. Bronchial thermoplasty: State of the art. Respirology 2022; 27:720-729. [PMID: 35692074 DOI: 10.1111/resp.14312] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/30/2022] [Indexed: 11/30/2022]
Abstract
Since the publication of a sham-controlled, randomized trial (AIR2) and subsequent marketing approval by the US Food and Drug Administration, we have significantly advanced our understanding of bronchial thermoplasty (BT)'s scientific basis, long-term safety, clinical efficacy and cost-effectiveness. In particular, the last 2 years have witnessed multiple research publications on several of these counts. In this review, we critically appraise our evolving understanding of BT's biologic underpinnings and clinical impact, offer an evidence-based patient workflow guide for the busy pulmonologist and highlight both current challenges as well as potential solutions for the researcher and the clinician.
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Affiliation(s)
- Muhammad Daniyal Hashmi
- Division of Pulmonary and Critical Care Medicine, Henry Ford Hospital, Wayne State University, Detroit, Michigan, USA
| | - Asad Khan
- Division of Pulmonary and Critical Care Medicine, University of Massachusetts Chan Medical School-Baystate, Springfield, Massachusetts, USA
| | - Majid Shafiq
- Division of Pulmonary and Critical Care Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts, USA
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10
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Rajan A, Bennetts K, Langton D. Plethysmography Derived Gas Trapping Lacks Utility in Predicting Response to Bronchial Thermoplasty. ERJ Open Res 2022; 8:00690-2021. [PMID: 35539441 PMCID: PMC9081540 DOI: 10.1183/23120541.00690-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/04/2022] [Indexed: 12/03/2022] Open
Abstract
There is a paucity of literature on measurable baseline parameters predicting response and guiding selection for bronchial thermoplasty. This study examines whether baseline gas trapping, as assessed by plethysmography, is associated with a response to bronchial thermoplasty at 12 months. 43 consecutive patients with severe asthma (mean±sd age 57.6±13.3 years) were evaluated at baseline and 12 months post bronchial thermoplasty. Data collected at both time points included spirometry, body plethysmography and four clinical outcome measures, namely Asthma Control Questionnaire (ACQ) score, annual exacerbation frequency, maintenance oral corticosteroid requirement and short-acting β-agonist use. At baseline, participants had severe airflow obstruction (forced expiratory volume in 1 s 49.1±15.8%) with marked gas trapping (residual volume (RV) 150.3±40.8%, RV/total lung capacity (TLC) 51.3±10.5%), poor symptom control (ACQ 3.3±1.0) and frequent exacerbations (median 4, interquartile range 8). 12 months after bronchial thermoplasty, significant improvements were observed in all four clinical outcome measures. However, baseline RV and RV/TLC were not significantly associated with changes in ACQ nor any other clinical outcome measure, and changes in RV and RV/TLC did not significantly correlate with a change in any clinical outcome measure. Plethysmography-derived gas trapping does not demonstrate utility in predicting response and guiding selection for bronchial thermoplasty. An improvement in gas trapping was not associated with positive clinical outcomes, suggesting that this may not be the dominant mode of action of bronchial thermoplasty in generating clinical improvement. This study examined whether measuring gas trapping by plethysmography could be used to predict response to bronchial thermoplasty; no association was foundhttps://bit.ly/3tJN1X8
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11
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12
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Chetty A, Nielsen HC. Targeting Airway Smooth Muscle Hypertrophy in Asthma: An Approach Whose Time Has Come. J Asthma Allergy 2021; 14:539-556. [PMID: 34079293 PMCID: PMC8164696 DOI: 10.2147/jaa.s280247] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 04/20/2021] [Indexed: 01/13/2023] Open
Abstract
Airway smooth muscle (ASM) cell dysfunction is an important component of several obstructive pulmonary diseases, particularly asthma. External stimuli such as allergens, dust, air pollutants, and change in environmental temperatures provoke ASM cell hypertrophy, proliferation, and migration without adequate mechanistic controls. ASM cells can switch between quiescent, migratory, and proliferative phenotypes in response to extracellular matrix proteins, growth factors, and other soluble mediators. While some aspects of airway hypertrophy and remodeling could have beneficial effects, in many cases these contribute to a clinical phenotype of difficult to control asthma. In this review, we discuss the factors responsible for ASM hypertrophy and proliferation in asthma, focusing on cytokines, growth factors, and ion transporters, and discuss existing and potential approaches that specifically target ASM hypertrophy to reduce the ASM mass and improve asthma symptoms. The goal of this review is to highlight strategies that appear ready for translational investigations to improve asthma therapy.
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Affiliation(s)
- Anne Chetty
- Tufts Medical Center, Tufts University, Boston, MA, USA
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13
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Langton D, Noble PB, Donovan GM. Response of individual airways in vivo to bronchial thermoplasty. J Appl Physiol (1985) 2021; 130:1205-1213. [PMID: 33630673 DOI: 10.1152/japplphysiol.00959.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bronchial thermoplasty (BT) is a treatment for moderate-to-severe asthma, which generally improves quality-of-life scores but not conventional measures of lung function. Newer methodologies have begun to demonstrate the underlying physiological changes and elucidate the mechanism of action. We postulated that systematic, computed tomography (CT)-based assessment of the response of individual airways to BT is feasible, and our aim was to determine the distribution of these responses and the relationship with airway size. Twenty patients meeting the European Respiratory Society/American Thoracic Society (ERS/ATS) definition of severe asthma underwent BT and assessment including CT, Asthma Control Questionnaire (ACQ), and spirometry. Treatment was structured so that the left and right lungs are treated sequentially with a midtreatment assessment providing an internal control. Pairs of CT scans were analyzed using a new semiautomatic processing algorithm that matched individual segmented airways for quantitative comparison. Cross-sectional airway lumen area from matched airway pairs in treated lungs increased on average by 6.4% after BT (P < 0.02) but showed no change in the untreated lung. Matched airway length was also unchanged. Breakdown by airway size showed amplified response in more distal airways, with the smallest quintile of measured airways dilating by 13.2% (P < 0.001). ACQ improved from 3.5 ± 0.9 to 1.9 ± 1.2 (P < 0.001). These data show that the response to BT in individual airways can be assessed by CT and that dilation is heterogeneous and predominant in distal compared with proximal airways. A CT-based approach may further our understanding of the physiological changes in BT and aid in the development of refined and personalized versions of the therapy.NEW & NOTEWORTHY CT scanning was used to evaluate the response of individual airways in patients undergoing bronchial thermoplasty. Airways dilated after treatment by 6.4% on average with substantial heterogeneity and a greater response in the most distal airways measured.
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Affiliation(s)
- David Langton
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, Victoria, Australia.,Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Western Australia, Australia
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
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14
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Langton D, Bennetts K, Thien F, Plummer V, Noble PB. Bronchial thermoplasty reduces ventilation heterogeneity measured by multiple breath nitrogen washout. Respir Res 2020; 21:308. [PMID: 33228688 PMCID: PMC7685663 DOI: 10.1186/s12931-020-01575-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/16/2020] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Despite demonstrated symptomatic benefit from bronchial thermoplasty (BT), the underlying pathophysiological benefits have been uncertain. The purpose of the present study was to relate clinical benefit after BT to changes in lung physiology, focusing on ventilation homogeneity assessed using multiple breath nitrogen washout (MBNW), and how this may be affected by changes in airway volume and resistance. METHODS Consecutive patients (n = 21) with severe asthma scheduled for BT, were evaluated at baseline, 6 weeks and 6 months after completion of treatment. Assessments included the Asthma Control Questionnaire (ACQ), medication usage, exacerbation frequency, spirometry, plethysmography and MBNW. Eighteen of these patients underwent detailed CT evaluation for the estimation of airway volume at baseline and then after the left lung had received BT treatment but prior to right lung treatment. Data are mean ± STDEV. RESULTS Patients responded to BT with an improvement in ACQ from 3.4 ± 0.8 at baseline to 2.0 ± 1.1 at 6 months (p < 0.001). Steroid requiring exacerbations fell from 3.1 ± 2.9 in the 6 months prior to BT to 1.4 ± 1.7 following BT (p < 0.001). Significant reductions in maintenance oral steroid dosing and short acting beta agonist use were observed. Airway volume measured by CT scanning significantly increased after treatment. The FEV1 improved from 1.34 ± 0.65 l to 1.52 ± 0.76 l (p = 0.024). The Residual Volume fell from 2.87 ± 0.89 l to 2.71 ± 0.93 l (p = 0.008) and Total Airway Resistance (Raw) from 10.58 ± 6.56 to 7.64 ± 3.74 cmH2O.s.l-1 (p = 0.020). The Lung Clearance Index (LCI) was 187 ± 63% predicted at baseline and improved after treatment from 12.7 ± 3.3 to 11.8 ± 2.4 (p = 0.049). The improvement in LCI correlated with the improvement in Raw (r = 0.463, p = 0.035). CONCLUSION Clinical benefit after BT is accompanied by improvements in lung physiology, including normalisation of lung homogeneity that seems to be driven by airway dilation and reduced resistance.
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Affiliation(s)
- David Langton
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, 2 Hastings Road, Frankston, VIC 3199 Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC Australia
| | - Kim Bennetts
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, 2 Hastings Road, Frankston, VIC 3199 Australia
| | - Francis Thien
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC Australia
- Department of Respiratory Medicine, Eastern Health, Box Hill, VIC Australia
| | - Virginia Plummer
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC Australia
| | - Peter B. Noble
- School of Human Sciences, The University of Western Australia, Crawley, WA Australia
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15
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Langton D, Banks C, Noble PB, Plummer V, Thien F, Donovan GM. The effect of bronchial thermoplasty on airway volume measured 12 months post-procedure. ERJ Open Res 2020; 6:00300-2020. [PMID: 33263039 PMCID: PMC7682672 DOI: 10.1183/23120541.00300-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 08/21/2020] [Indexed: 11/05/2022] Open
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.
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Affiliation(s)
- David Langton
- Dept of Thoracic Medicine, Frankston Hospital, Peninsula Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Ceri Banks
- Dept of Thoracic Medicine, Frankston Hospital, Peninsula Health, Melbourne, Victoria, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Virginia Plummer
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Francis Thien
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia.,Dept of Respiratory Medicine, Eastern Health, Melbourne, Victoria, Australia
| | - Graham M Donovan
- Dept of Mathematics, University of Auckland, Auckland, New Zealand
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16
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Wang KCW, Donovan GM, James AL, Noble PB. Asthma: Pharmacological degradation of the airway smooth muscle layer. Int J Biochem Cell Biol 2020; 126:105818. [PMID: 32707120 DOI: 10.1016/j.biocel.2020.105818] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 07/15/2020] [Accepted: 07/20/2020] [Indexed: 12/23/2022]
Abstract
Asthma: A disease characterised by excessive and variable airway narrowing, and pathologies of inflammation and remodelling, particularly thickening of the airway smooth muscle (ASM). Treatment approaches dilate narrowed airways and reduce inflammation; however, remodelling seems largely neglected. This review considers the evolution of remodelling in asthma and whether conventional hypotheses that inflammation causes ASM thickening has mislead the medical community into thinking that anti-inflammatories will remedy this ASM defect. There is instead reasonable evidence that ASM thickening occurs independently of inflammation, such that therapies should employ strategies to directly modify ASM growth. Lessons have been learned from the use of untargeted bronchial thermoplasty and there should also be consideration of pharmacological therapies to ablate ASM. We discuss several new approaches to target ASM remodelling in asthma. A major current obstacle is our inability to image the ASM layer and assess treatment response. In this regard, polarisation-sensitive optical coherence tomography offers future promise.
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Affiliation(s)
- Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, 6009, Western Australia, Australia; Telethon Kids Institute, The University of Western Australia, Nedlands, 6009, Western Australia, Australia.
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, 1142, New Zealand
| | - Alan L James
- Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, 6009, Western Australia, Australia; Medical School, The University of Western Australia, Nedlands, 6009, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, 6009, Western Australia, Australia
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17
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Langton D, Lee P. Bronchial thermoplasty: Redefining its role. Respirology 2020; 25:981-986. [PMID: 32567121 DOI: 10.1111/resp.13887] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/10/2020] [Accepted: 04/29/2020] [Indexed: 02/01/2023]
Abstract
In this review, we trace (i) the origins of bronchial thermoplasty, (ii) the development of a solid evidence base for efficacy and safety, (iii) the emerging understanding of the pathophysiological mechanisms of action and (iv) the place in therapy today. Future challenges are then discussed.
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Affiliation(s)
- David Langton
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, Melbourne, VIC, Australia.,Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
| | - Pyng Lee
- Division of Respiratory and Critical Care Medicine, National University Hospital, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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