Safety and efficacy of bronchial thermoplasty in symptomatic, severe asthma

Bronchial thermoplasty (BT) is designed to reduce airway smooth muscle and improve asthma control.

This study was conducted to determine the safety and efficacy of this procedure in subjects with symptomatic, severe asthma.

Adults who were symptomatic despite treatment with fluticasone or equivalent at more than 750 mug/day, a long-acting beta(2)-agonist, and other medications, which could include 30 mg or less of oral prednisolone/day, were randomized to BT or to a control group. After treatment, subjects entered a 16-week steroid stable phase (Weeks 6-22), a 14-week steroid wean phase (Weeks 22-36), and a 16-week reduced steroid phase (Weeks 36-52).

BT resulted in a transient worsening of asthma symptoms. Seven hospitalizations for respiratory symptoms occurred in 4 of 15 BT subjects during the treatment period. Five hospitalizations were within 3 days of treatment. Two subjects had segmental collapse involving the most recently treated lobe; one required bronchoscopy and aspiration of a mucus plug. There were no hospitalizations during this period in the 17 control subjects. The rate of hospitalizations was similar in both groups in the post-treatment period. At 22 weeks, BT subjects had significant improvements versus control subjects in rescue medication use (-26.6 +/- 40.1 vs. -1.5 +/- 11.7 puffs/7 d, P < 0.05), prebronchodilator FEV(1)% predicted (14.9 +/- 17.4 vs. -0.94 +/- 22.3%, P = 0.04), and Asthma Control Questionnaire scores (-1.04 +/- 1.03 vs. -0.13 +/- 1.00, P = 0.02). Improvements in rescue medication use and Asthma Control Questionnaire scores remained significantly different from those of controls at 52 weeks.

BT is associated with a short-term increase in asthma-related morbidity. However, there is preliminary evidence of long-lasting improvement in asthma control. Clinical trial registered with www.clinicaltrials.gov (NCT 00214539).