A Prospective Feasibility Study of Bronchial Thermoplasty in the Human Airway

BACKGROUND: Bronchial thermoplasty is a novel procedure being developed as a potential treatment for asthma. Experience with animal studies has enabled development of appropriate reliable equipment, definition of therapeutic parameters, and descriptions of tissue effects of treatment. STUDY OBJECTIVES: This study was undertaken to assess the feasibility and general safety of the application of bronchial thermoplasty in the human airway, and to determine if the reduction in airway smooth muscle seen in animal studies could be replicated. DESIGN: A prospective study. SETTING: Academic thoracic surgery center. PARTICIPANTS: Nine patients scheduled to undergo lung resection for suspected or proven lung cancer. INTERVENTIONS: Bronchial thermoplasty was performed during routine preoperative bronchoscopy up to 3 weeks prior to prescheduled lung resection. Treatment was limited to areas of the segmental bronchi within the lobe that was to be removed. Treated airways were inspected via bronchoscopy at the time of thoracotomy, and were examined histologically following surgical resection. RESULTS: There were no adverse clinical effects of the procedure, including no new symptoms and no unscheduled visits for medical care. Treated sites exhibited slight redness and edema of the mucosa within 2 weeks of treatment, and appeared normal at later time points. There was narrowing (visually estimated at 25 to 50%) in four airways in two subjects examined at 5 days and 13 days after treatment, with excess mucus in two of these airways. There was no bronchoscopic evidence of scarring in any of the airways examined. Histologic examination showed a reduction in airway smooth muscle, and the extent of the treatment effect was confined to the airway wall and the immediate peribronchial region. CONCLUSION: Application of bronchial thermoplasty to the human airway appears to be well tolerated. Treatment resulted in significant reduction of smooth muscle mass in the airways. Bronchial thermoplasty may provide therapeutic benefit in disease states such as asthma.