Bronchial thermoplasty, approved by the FDA to treat adults with severe asthma, shrinks smooth muscle in the lungs, which prevents them from tightening up.

About 5% to 10% of people with asthma have illness that can’t be controlled with medicine, inhalers or other therapies, according to the Cleveland Clinic.

Now, a new clinical trial of nearly 300 patients reports that their symptoms had significantly improved five years after their procedure. They had fewer severe asthma attacks, emergency department visits and hospitalizations, and used less corticosteroid medication.

“The data continues to show in multiple studies that the procedure works, that it’s durable over five years and there aren’t any major adverse event effects,” said study author Dr. Geoffrey Chupp, a professor of medicine at Yale University. “I think it supports that bronchial thermoplasty should continue to be used in appropriate patients.”

While drugs known as biologics — another new type of therapy — are increasing in number and reducing asthma attacks in many patients, bronchial thermoplasty is helpful for those who don’t respond to those drugs, Chupp said. Some are treated both with biologics and the surgery.

The study included 284 American and Canadian patients between 18 and 65 years of age who had bronchial thermoplasty. About 80% were followed for five years. They had been taking corticosteroids and long-acting beta-agonists to control their asthma. Their asthma attacks, emergency visits, hospitalizations and medication use were tracked for 12 months prior to surgery and for five years after.

Get the full story at webmd.com.