With normal breathing, the airways of the
lungs are fully open as in this cross section of an airway. For a person with asthma, the
airway’s smooth muscle that circles the airway may become thicker than normal. During
an asthmatic attack, in response to an asthma trigger, such as an allergen or irritant,
the airway smooth muscle may contract, leading to airway narrowing and breathing difficulties.
During bronchial thermoplasty, a small flexible tube is advanced into the airway through a
standard flexible bronchoscope placed through the mouth or nose. No incision is required.
The Alair device has an expandable wire basket at the tip, and when it is expanded, the four
arms of the basket come in contact with and fit snuggly against the airway wall. The expanded
basket will then deliver controlled radial frequency energy for about 10 seconds to heat
the airway smooth muscle. About 1/3 of the targeted lung areas are treated during a single
session. A total of 3 procedures are currently needed for complete treatment. Once the treatment
session is completed, the device and bronchoscope are removed. The controlled heat delivered
during bronchial thermoplasty is designed to reduce the amount of airway smooth muscle
in the airway wall. By reducing the amount of airway smooth muscle, the procedure may
reduce the ability of the airway walls to contract and narrow in response to irritation,
infection, or inflammation.