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


OBJECTIVE
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.


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.
Cox
Gerard
G
M.B., Firestone Institute for Respiratory Health-T2123, St. Joseph's Healthcare, 50 Charlton Avenue, East Hamilton, ON L8N 4A6, Canada. coxp@mcmaster.ca
Miller
John D
JD
McWilliams
Annette
A
Fitzgerald
J Mark
JM
Lam
Stephen
S
D000328:Adult; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology* / Q000601:surgery*; D016535:Bronchial Hyperreactivity / Q000503:physiopathology / Q000601:surgery*; D001999:Bronchoscopy; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D006979:Hyperthermia, Induced / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012129:Respiratory Function Tests; D016896:Treatment Outcome
D018927:Anti-Asthmatic Agents; D005938:Glucocorticoids