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Long-term (5 year) safety of bronchial thermoplasty: Asthma Intervention Research (AIR) trial

Neil C Thomson1*, Adalberto S Rubin2, Robert M Niven3, Paul A Corris4, Hans Christian Siersted5, Ronald Olivenstein6, Ian D Pavord7, David McCormack8, Michel Laviolette9, Narinder S Shargill10, Gerard Cox11 and the AIR Trial Study Group

Author affiliations

1 Gartnavel General Hospital, University of Glasgow, Glasgow, UK

2 Irmandade Santa Casa de Misericórdia da Porto Alegre, Brazil

3 University Hospital of South Manchester and University of Manchester, Manchester, UK

4 Department of Respiratory Medicine, Freeman Hospital, Newcastle University, Newcastle, UK

5 Odense University Hospital, Odense, Denmark

6 Montreal Chest Institute, McGill University, Montreal, Canada

7 Glenfield General Hospital, University Hospitals of Leicester NHS Trust, Leicester, UK

8 London Health Sciences Center, Ontario, Canada

9 Laval Hospital, Laval University, Quebec, Canada

10 Asthmatx, Inc., Sunnyvale, CA, US

11 St. Joseph's Healthcare, McMaster University, Hamilton, Canada

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Citation and License

BMC Pulmonary Medicine 2011, 11:8  doi:10.1186/1471-2466-11-8

Published: 11 February 2011



Bronchial thermoplasty (BT) is a bronchoscopic procedure that improves asthma control by reducing excess airway smooth muscle. Treated patients have been followed out to 5 years to evaluate long-term safety of this procedure.


Patients enrolled in the Asthma Intervention Research Trial were on inhaled corticosteroids ≥200 μg beclomethasone or equivalent + long-acting-beta2-agonists and demonstrated worsening of asthma on long-acting-β2-agonist withdrawal. Following initial evaluation at 1 year, subjects were invited to participate in a 4 year safety study. Adverse events (AEs) and spirometry data were used to assess long-term safety out to 5 years post-BT.


45 of 52 treated and 24 of 49 control group subjects participated in long-term follow-up of 5 years and 3 years respectively. The rate of respiratory adverse events (AEs/subject) was stable in years 2 to 5 following BT (1.2, 1.3, 1.2, and 1.1, respectively,). There was no increase in hospitalizations or emergency room visits for respiratory symptoms in Years 2, 3, 4, and 5 compared to Year 1. The FVC and FEV1 values showed no deterioration over the 5 year period in the BT group. Similar results were obtained for the Control group.


The absence of clinical complications (based on AE reporting) and the maintenance of stable lung function (no deterioration of FVC and FEV1) over a 5-year period post-BT in this group of patients with moderate to severe asthma support the long-term safety of the procedure out to 5 years.