Chest
Volume 127, Issue 6, June 2005, Pages 1999-2006
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Clinical Investigations
A Prospective Feasibility Study of Bronchial Thermoplasty in the Human Airway

https://doi.org/10.1378/chest.127.6.1999Get rights and content

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.

Section snippets

Materials and Methods

The protocol for this clinical study was approved by the Research Ethics Board of St. Joseph's Healthcare, Hamilton, ON, and the Medical Devices Bureau, Therapeutic Products Division, of Health Canada. Informed consent was obtained from all subjects prior to their participation in the study.

Results

A total of nine patients gave consent for their participation in the study between January and May 2000. Of these, eight patients were treated. Patient 4–07 was not treated because the geometry of airways in right upper lobe made it difficult to place the bronchoscope and catheter at the targeted sites. The treated patients included four male and four female white patients ranging in age from 52 to 78 years (mean age, 65 ± 8.3 years SD). Pertinent patient demographics are shown in Table 1.

All

Discussion

This study reports the first deployment in humans of the Alair System, a novel device for performing bronchial thermoplasty that involves the delivery of mild, controlled heat to the airway wall. The delivery of radiofrequency energy to the airway wall reduces the amount of ASM. We hypothesize that such a physical approach could be an effective treatment for asthma if it results in a diminished potential for airway narrowing due to bronchoconstriction.5 Radiofrequency energy has been safely and

Conclusion

We have demonstrated that bronchial thermoplasty is well tolerated in humans. There were no clinically significant adverse events associated with this treatment, either acutely or during follow-up periods of up to 20 days. There were no unexpected findings at histology, and the anticipated potentially beneficial effect of this treatment to reduce the amount of ASM in the bronchial wall was observed. These observations provide a strong impetus for further studies of bronchial thermoplasty as a

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    Citation Excerpt :

    Research has shown that bronchial thermoplasty can greatly improve asthma control up to 5 years post-procedure in severe asthmatics, and results are similar between allergic and non-allergic patients [58]. Histologically, there is no evidence of scarring post-procedure [59]. There is, however, a lack of data on the efficacy of bronchial thermoplasty in different asthma endotypes.

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