Bronchial Thermoplasty in Patients With Severe Asthma at 5 Years: The Post-FDA Approval Clinical Trial Evaluating Bronchial Thermoplasty in Severe Persistent Asthma Study

Chest. 2022 Mar;161(3):614-628. doi: 10.1016/j.chest.2021.10.044. Epub 2021 Nov 10.


Background: Bronchial thermoplasty is a device-based treatment for subjects ≥ 18 years of age with severe asthma poorly controlled with inhaled corticosteroids and long-acting beta-agonists. The Post-FDA Approval Clinical Trial Evaluating Bronchial Thermoplasty in Severe Persistent Asthma (PAS2) study collected data on patients with severe asthma undergoing this procedure.

Research question: What are the 5-year efficacy and safety results in patients with severe asthma who have undergone bronchial thermoplasty?

Study design and methods: This was a prospective, open-label, observational, multicenter study conducted in the United States and Canada. Subjects 18 to 65 years of age who were taking inhaled corticosteroids ≥ 1,000 μg/d (beclomethasone or equivalent) and long-acting beta-agonists ≥ 80 μg/d (salmeterol or equivalent) were included. Severe exacerbations, hospitalization, ED visits, and medication usage were evaluated for the 12 months prior to and at years 1 through 5 posttreatment. Spirometry was evaluated at baseline and at years 1 through 5 posttreatment.

Results: A total of 284 subjects were enrolled at 27 centers; 227 subjects (80%) completed 5 years of follow-up. By year 5 posttreatment, the proportion of subjects with severe exacerbations, ED visits, and hospitalizations was 42.7%, 7.9%, and 4.8%, respectively, compared with 77.8%, 29.4%, and 16.1% in the 12 months prior to treatment. The proportion of subjects on maintenance oral corticosteroids decreased from 19.4% at baseline to 9.7% at 5 years. Analyses of subgroups based on baseline clinical and biomarker characteristics revealed a statistically significant clinical improvement among all subgroups.

Interpretation: Five years after treatment, subjects experienced decreases in severe exacerbations, hospitalizations, ED visits, and corticosteroid exposure. All subgroups demonstrated clinically significant improvement, suggesting that bronchial thermoplasty improves asthma control in different asthma phenotypes.

Clinical trial registration:; No.: NCT01350336; URL: www.

Clinicaltrials: gov.

Keywords: asthma subgroups; bronchial thermoplasty; corticosteroid exposure; severe asthma; severe exacerbations.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use
  • Asthma* / drug therapy
  • Asthma* / surgery
  • Bronchial Thermoplasty* / methods
  • Humans
  • Prospective Studies
  • Quality of Life


  • Adrenal Cortex Hormones

Associated data