Washington ? In a radical experiment, doctors are snaking wires inside the lungs of asthma patients to essentially burn off some of the tissue that blocks their ability to breathe.

Called bronchial thermoplasty, the procedure is the first attempt at a nondrug treatment for asthma.

It’s not without risk. Irritating those super-sensitive airways can trigger wheezing, and no one knows the long-term effects. Nor does it promise a cure.

But the hope is that physically altering spasm-prone airways might one day help thousands of patients with hard-to-control asthma breathe easier.

“People still get very sick from asthma. People still die of asthma. You’d think we’d have better control, but it seems to be escalating rather than going down,” says Dr. Michael Simoff, interventional pulmonology chief at Detroit’s Henry Ford Medical Center, one of 17 U.S. hospitals, and 29 worldwide, enrolling patients in the experiment.

More than 20 million Americans have asthma, and the chronic lung disease is on the rise. While medications can be very effective in preventing and treating asthma attacks, the disease kills 5,000 people every year and accounts for 2 million emergency-room visits.

The thermoplasty experiment targets patients who do poorly despite multiple medications – based on evidence that overgrown muscle tissue lining air tubes inside the lungs is one of asthma’s underlying causes.

Bronchial thermoplasty promises to get rid of half of that thickened muscle, in hopes that the airways will behave more normally. Doctors sedate patients and thread a bronchoscope – a lighted catheter – through the nose or throat and into the branch-like airways that fill the lungs. A wire basket on the tip is inflated to touch the airway walls, and radiofrequency waves are beamed through those wires, basically disintegrating the muscle tissue.

It takes three outpatient treatments, a half-hour each, to inch the RF device throughout the lungs, reaching main airways.

Coughing and wheezing are common side effects for a few days, but clear once lung irritation subsides, says Dr. Gerard Cox of Canada’s McMaster University, who reported the first study results – on 16 patients tracked for two years – this month in the American Journal of Respiratory and Critical Care Medicine.

Most breathed a little bit easier on an asthma test and had more symptom-free days by three months after treatment, he reports. A second pilot study found similar improvements, researchers reported Monday at an American Thoracic Society meeting.