Doctors testing a procedure to zap airways of asthmatics
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.
The procedure, called bronchial thermoplasty, is the first attempt at a non drug treatment for asthma.
It's not without risk. Irritating those super sensitive airways can trigger wheezing, and no one knows the long-term effects. But the hope is that using radio frequency waves to alter spasm-prone airways might one day help thousands of severe asthmatics to breathe easier.
``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, of Detroit's Henry Ford Medical Center, one of 17 US hospitals, and 29 worldwide, enrolling patients in the experiment.
``We have a real potential here, I think, to influence a very common disease."
More than 20 million Americans have asthma, and the chronic lung disease is on the rise. Medications can be very effective in preventing and treating asthma attacks, but the thermoplasty experiment targets patients who do poorly despite multiple medications.
So-called smooth muscle encircles human airways. When something irritates the lungs, the muscle goes into a spasm, narrowing air passages to leave patients gasping. Swelling of the airway tissues further closes off their air. Repeated attacks thicken the muscle, so airways can become habitually narrowed, and the muscle becomes even more sensitive to asthma triggers.
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.
Simoff compares it to a microwave oven, which cooks meat without scorching the outer skin like a grill would. The RF waves work similarly: They appear to beam through the airway's thin lining without scarring it, while heating smooth muscle underneath to 149 degrees.
Now a clinical trial funded by device manufacturer Asthmatx Inc. is enrolling at least 300 severe asthmatics.
Physically manipulating already hypersensitive airways is uncharted territory. It's crucial to track recipients for at least five years to watch for late-term side effects, cautioned Dr. Michael Silver of Chicago's Rush University Medical Center, who is monitoring the research and said he is skeptical that it will pan out.
Among concerns: Do the airways become too weak, or does late scarring arise? How long do any benefits last?
Silver also wonders about the price tag. Asthmatx won't yet estimate that, but simple bronchoscopies cost up to $2,000 each.
The procedure doesn't replace asthma medications, said Dr. Rand Sutherland of Denver's National Jewish Research and Medical Center. But he's testing it because too many patients run out of options: ``We long for something else." 