Bronchial thermoplasty is a non-surgical procedure that uses controlled heat to reduce airway muscle in the lungs, helping people with severe asthma who don’t respond well to standard medications. It was approved by the FDA and works by delivering radiofrequency energy at 65°C (149°F) through a catheter threaded into the airways during a bronchoscopy. The goal is to thin out the layer of smooth muscle that causes airways to clamp down during asthma attacks.
How It Works Inside the Airways
In asthma, the smooth muscle lining your airways is often thicker than normal. When triggered, this muscle contracts and narrows the airway, making it hard to breathe. Bronchial thermoplasty targets that muscle directly. A thin, flexible catheter with an expandable wire tip is guided into the airways through the mouth or nose. Once in position, the wire delivers radiofrequency energy that heats the airway wall to 65°C for about 10 seconds at a time.
At temperatures above 55°C, the protein structures inside muscle cells break apart. The heat destroys the contractile machinery of the smooth muscle, permanently reducing its ability to squeeze the airway shut. Early animal studies showed nearly complete destruction of smooth muscle in treated areas, and when researchers tried to provoke airway constriction in those same areas, it didn’t happen.
There’s also evidence that the heat may disrupt nerve fibers embedded in the airway wall. These nerves play a role in triggering bronchospasm through local reflexes, so damaging them could further reduce the airway’s tendency to overreact. This nerve disruption may help explain why the procedure improves symptoms even though it only reaches the larger, more central airways rather than the smallest branches deep in the lungs.
Who Is Eligible
Bronchial thermoplasty is reserved for adults between 18 and 65 with severe persistent asthma that remains poorly controlled despite being on the highest level of standard medications. You won’t be considered a candidate until reversible causes of poor asthma control have been investigated and your medication regimen has been fully optimized. Adults over 65 may still be considered on a case-by-case basis after a detailed risk-benefit discussion.
To qualify, your asthma needs to be in a stable phase. You can’t have had an exacerbation or respiratory infection in the two weeks before the procedure, and your lung function on the day of treatment must be at least 80% of your personal baseline. You also need to have been a nonsmoker for at least one year and on stable maintenance medications for four weeks.
Several situations rule out the procedure entirely: a current asthma flare-up, a history of life-threatening asthma requiring mechanical ventilation in the past two years, or prior bronchial thermoplasty treatment. Poorly controlled conditions like heart disease or significant abnormalities on a recent chest X-ray (such as a collapsed lung or infection) are also reasons to hold off.
What Happens During the Three Sessions
The treatment is spread across three separate bronchoscopy sessions, each spaced about three weeks apart. This staged approach is deliberate: treating the entire airway system at once would cause too much inflammation. Each session lasts 30 to 45 minutes and involves roughly 30 to 40 individual heat activations along the airway walls.
The first session treats the right lower lobe of the lung. The second session treats the left lower lobe. The third and final session covers both upper lobes. The right middle lobe is intentionally left untreated because of its narrow drainage anatomy, which makes it more vulnerable to complications. After each session, you recover in the hospital for about two hours before going home the same day.
Recovery After Each Session
The days immediately following each treatment session are the most challenging part of the process. Asthma symptoms commonly flare up as the airways respond to the thermal injury. In one study tracking immediate complications, asthma exacerbation was the most frequent issue, occurring in about a third of patients after the first session, more than half after the second, and up to 75% after the third. Other possible short-term effects include respiratory infections and minor coughing up of blood.
Lung function also dips temporarily after each session, with the most significant drop happening after the third treatment. These effects are expected and typically resolve within a week or so. Your doctor will likely increase your corticosteroid dose before and after each session to help manage this temporary worsening. Most people return to their normal routine within a few days of each session, though the full course of treatment spans roughly two to three months from start to finish.
How Well It Works
The primary benefit of bronchial thermoplasty is fewer severe asthma episodes over time. A pooled analysis found that the procedure was associated with a 47% reduction in the combined rate of hospital admissions and emergency department visits compared to what would be expected without treatment. Patients also reported significantly fewer missed days of work, school, and daily activities, with one study showing a 66% reduction in lost days.
It’s worth understanding what this procedure doesn’t do: it doesn’t cure asthma, and most patients still need their medications afterward. The goal is to reduce the frequency and severity of flare-ups, cut down on emergency care, and improve day-to-day quality of life. Some patients are able to lower their medication doses over time, but that varies from person to person.
Long-Term Durability
One of the most important questions about any procedure is whether the results last. A follow-up study published in The Lancet Respiratory Medicine tracked patients for more than 10 years after treatment. The findings were encouraging: the proportion of patients experiencing severe exacerbations at the 10-year mark (25%) was essentially the same as at the 1-year mark (24%) and the 5-year mark (22%). In other words, the benefits didn’t fade over time.
The long-term safety picture was largely reassuring, with one notable finding. About 7% of patients who had normal CT scans before treatment developed bronchiectasis, a condition where airways become permanently widened, after the procedure. Most of these cases were classified as mild. Overall, researchers concluded that bronchial thermoplasty offers durable benefit with an acceptable safety profile for patients whose asthma isn’t controlled by medications alone.
Limitations to Keep in Mind
Bronchial thermoplasty only reaches airways that are large enough for the catheter to access. The smallest airways deep in the lungs, which also contribute to asthma symptoms, are left untreated. The procedure also can’t be repeated if symptoms return or if the initial results are insufficient, since prior treatment is listed as an absolute contraindication for a second round.
Availability is another practical consideration. The procedure requires specialized equipment (the Alair Bronchial Thermoplasty System, made by Boston Scientific) and a pulmonologist trained in the technique. Not every hospital offers it, so you may need to travel to a center with experience performing it. The staged nature of treatment, requiring three separate sessions with recovery periods in between, also means a time commitment of several months from start to full recovery.