Bronchial Thermoplasty

Bronchial thermoplasty is a procedure sometimes used to treat adults with severe asthma.1 It is done to reduce the amount of smooth muscle that surrounds the airways. The procedure was approved by the US Food and Drug Administration in 2010 for people ages 18 years and older whose asthma is not well controlled with inhaled corticosteroids and long-acting beta agonists.2

How is bronchial thermoplasty done?

A thin tube, called a bronchoscope, is inserted through your mouth or nose. The bronchoscope has a light and a camera, which allows your doctor to see inside your airways. The bronchoscope used for this procedure also has a “wire electrode array.”3 This device expands, touching the sides of the airways. The device heats the airway smooth muscle.

When there is less smooth muscle, the airways do not become as narrow during an asthma attack.3 The airways also seem to be less sensitive (“hyperresponsive”) after bronchial thermoplasty.2

Bronchial thermoplasty is done in three procedures. The procedures are done at least three weeks apart.1,4 Each procedure takes 30 to 45 minutes.2

Who can be treated with bronchial thermoplasty?

There are different recommendations about who can be treated with bronchial thermoplasty. The American Thoracic Society strongly recommends only doing the procedure as part of a registry or clinical study.4 They note that additional high-quality studies of bronchial thermoplasty are necessary. More information is needed about the benefits, risks, and long-term safety.

The Global Initiative for Asthma Management guidelines say that bronchial thermoplasty is an option for some adults with the most severe asthma.1 They recommend trying to find medications that work before trying the procedure.

Who should not be treated with bronchial thermoplasty?

People with COPD, bronchiectasis (damaged and scarred airways), and other serious lung problems should not have this procedure.2 Bronchial thermoplasty is only for people with asthma.

Only certain people were allowed to be in studies of bronchial thermoplasty. In the largest trial, called AIR2, only people with an FEV1 of 60% or more were allowed.5 FEV1 measures how much air you can forcefully exhale in one second. People who frequently need oral corticosteroids or have life-threatening asthma could not be in the study.5 People with frequent hospitalizations, chest colds, or sinus infection could not participate.5 Therefore, the effects of the procedure on these people are not known.4

What studies have been done of bronchial thermoplasty?

There are three randomized trials of bronchial thermoplasty.

The AIR trial included 112 people with moderate to severe asthma.6 Half were randomly assigned to get bronchial thermoplasty. The other half continued to get usual care. This study was not blinded, which means that the participants and researchers knew which treatment they got. The outcomes were studied for one year after the procedure.

The RISA trial included 34 patients with severe asthma.7 Just like in AIR, half were randomly assigned to bronchial thermoplasty, and half got usual care. This study was not blinded either and it lasted for one year.

The AIR2 trial is the largest trial of bronchial theromplasty.5 It included 196 people who were randomly assigned to bronchial thermoplasty. Another 101 people were assigned to a fake (sham) procedure. The people who got the sham treatment went through all the same steps as the people who got the real treatment. The only difference was that the bronchoscope did not actually heat the airways. This meant that the study was blinded, so none of the study participants knew which treatment they got. Blinded studies are higher quality than un-blinded studies. People tend to feel better after they are treated, even if they have a fake treatment. This is called the placebo effect. Studies produce better results if no one knows whether they got the real or fake treatment.

The researchers studied the people in AIR2 who got bronchial thermoplasty for five years after the procedure.8 Their results provide some information about long-term effects of the treatment.

What have studies shown about the benefits of bronchial thermoplasty?

All three studies showed that bronchial thermoplasty improved quality of life.2,4 People who had the procedure missed fewer days of school and work.4

In AIR, people had fewer mild asthma attacks after bronchial thermoplasty than before.6 AIR2 studied severe asthma attacks. It showed that 26.3% of people who had bronchial thermoplasty and 39.8% of people who had the sham treatment had severe asthma attacks in the year after the procedure.5 The number of attacks per person per year was 32% lower for the people who got the real treatment. Five years after having bronchial thermoplasty, people have fewer severe asthma attack than they did the year before their procedure.8

AIR2 also showed that the people who got the real treatment had fewer emergency department visits between six weeks after the treatment and one year.5 Five years later, emergency visits were down 78% in the people who got the real procedure.8 The average dose of inhaled corticosteroids was also down 17%.8

Other benefits seen in AIR and RISA were less use of rescue medication and better asthma control for up to one year.2,6,7 In AIR2, there was no difference in symptoms, asthma control, and rescue medication use between the real and fake treatment.5

The American Thoracic Society called for more information from high quality studies. Specifically, more needs to be known about whether people have fewer asthma attacks and better long-term lung function after the procedure.4

What are the risks of bronchial thermoplasty?

In the first three months after bronchial thermoplasty, asthma attacks actually increase.1 Hospital admissions go up by about 3% to 15%.2 Some people have more asthma symptoms and fever.2

Bronchial thermoplasty does not seem to improve lung function.2 In AIR2, peak flow and FEV1 were no different for the people who got the real and fake treatments.5

The American Thoracic Society and the Global Strategy for Asthma Management and Prevention guidelines agree that more long-term safety studies are needed.1,4

Written by: Sarah O'Brien | Last Reviewed: May 2016.
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