Bronchial thermoplasty (BT) is a specialized, non-pharmacological treatment for adults suffering from severe, persistent asthma. It is a minimally invasive procedure that utilizes a medical device to address structural changes within the lungs that contribute to breathing difficulty. BT is intended for individuals whose asthma remains poorly controlled despite adhering to the standard regimen of inhaled medications, aiming to reduce the frequency and severity of asthma attacks.
The Science Behind the Treatment
Asthma is characterized by chronic inflammation and airway remodeling, which involves a thickening of the airway smooth muscle (ASM) surrounding the bronchial tubes. This excess muscle mass is hyper-responsive to triggers, constricting the airways intensely during an asthma flare-up and severely limiting airflow.
Bronchial thermoplasty directly targets this thickened muscle using controlled thermal energy. A specialized catheter delivers radiofrequency waves to the airway wall, gently heating the tissue to a specific temperature, typically around 65 degrees Celsius, for approximately ten seconds at a time.
The application of this mild heat causes a reduction in the total mass of the ASM tissue. By reducing the volume of this constricting muscle, the airways become less reactive to asthma triggers. This translates into a wider opening for air to pass through, which helps limit the severity of future bronchospasms and improve breathing.
Patient Suitability
Bronchial thermoplasty is not a first-line treatment, but an additional therapeutic option for a specific subset of patients. Candidates must have a confirmed diagnosis of severe, persistent asthma that is not adequately managed with conventional drug therapies. This typically includes patients who continue to experience frequent asthma attacks despite taking high-dose inhaled corticosteroids and long-acting beta-agonists.
The procedure is approved for patients 18 years of age and older. Lung function is a factor, with most suitable candidates having a pre-bronchodilator forced expiratory volume in one second (FEV1) that is at least 60% of the predicted value. Patients must also be stable, meaning they should not have had a recent respiratory infection or an asthma exacerbation requiring a change in systemic steroid dose within the preceding weeks. Individuals with a history of significant smoking or the presence of a pacemaker or defibrillator are excluded from consideration.
The Step-by-Step Procedure
The treatment is performed in a hospital or specialty clinic setting using a flexible tube called a bronchoscope. The patient is given either moderate sedation or general anesthesia for comfort. The bronchoscope is guided through the mouth or nose into the lungs to access the airways.
A small catheter is passed through the working channel of the bronchoscope to deliver radiofrequency energy to the targeted airways. The medical team treats one lung lobe at a time, repeating the energy delivery approximately 60 times within that lobe to cover all accessible airways. Each session usually takes less than an hour.
To ensure patient safety and allow the lungs time to recover, the complete treatment is delivered in three separate sessions. These sessions are scheduled approximately three weeks apart. The first two sessions typically treat the lower lobes of the right and left lungs, while the final session targets the airways in both upper lobes.
Expected Outcomes and Safety Profile
Bronchial thermoplasty is intended to improve asthma control and the patient’s quality of life, but it is not a cure for the chronic condition. Clinical trials have demonstrated sustained benefits for patients up to five years following the procedure. These benefits include a significant reduction in the rate of severe asthma exacerbations, fewer visits to the emergency department for respiratory symptoms, and a decrease in the use of rescue medications. For some individuals, the treatment may also lead to a reduced need for maintenance oral corticosteroids.
The most common immediate side effect is a temporary worsening of asthma symptoms, such as wheezing, cough, and shortness of breath, which occurs within a day of the procedure. These short-term symptoms are usually managed with standard care and resolve within about a week.
Long-term follow-up studies indicate that the procedure is safe, showing no increase in respiratory-related hospitalizations or a decline in lung function over a five-year period. The structural integrity of the airways remains stable years after the treatment is completed.