Bronchial thermoplasty for asthma.

RATIONALE

Bronchial thermoplasty (BT) reduces the potential for smooth muscle-mediated bronchoconstriction by reducing the mass of smooth muscle in the walls of conducting airways.

OBJECTIVES

This study was conducted to examine the safety and impact on lung function and airway responsiveness of BT over 2 yr.

METHODS

The safety of BT was studied in 16 subjects with mild to moderate asthma. Baseline and 12-wk post-treatment measurements included spirometry, methacholine challenge, daily diary recordings of peak flow, symptoms, and medication usage. Subjects completed follow-up evaluations at 12 wk, 1 yr, and 2 yr.

MEASUREMENTS AND MAIN RESULTS

The procedure was well tolerated; side effects were transient and typical of what is commonly observed after bronchoscopy. All subjects demonstrated improvement in airway responsiveness. The mean PC(20) increased by 2.37 +/- 1.72 (p < 0.001), 2.77 +/- 1.53 (p = 0.007), and 2.64 +/- 1.52 doublings (p < 0.001), at 12 wk, 1 yr, and 2 yr post-procedure, respectively. Data from daily diaries collected for 12 wk indicated significant improvements over baseline in symptom-free days (p = 0.015), morning peak flow (p = 0.01), and evening peak flow (p < or = 0.007). Spirometry measurements remained stable throughout the study period.

CONCLUSIONS

BT is well tolerated in patients with asthma and results in decreased airway hyperresponsiveness that persists for at least 2 yr.