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Device Tested That Zaps Asthmatic Airways
- By LAURAN NEERGAARD, AP Medical Writer
Tuesday, May 23, 2006

(05-23) 16:20 PDT WASHINGTON, (AP) --

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
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. 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.

"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. 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.

So-called smooth muscle encircles those airways. When something
irritates the lungs, the muscle spasms, narrowing air passages to leave
patients gasping. Swelling further closes off their air. Repeated
attacks thicken 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 -
hot enough that some muscle tissue basically disintegrates.

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 of 108 patients found similar improvements in the half
given thermoplasty, researchers reported Monday at an American Thoracic
Society meeting.

Now under way is the real test, a clinical trial funded by device
manufacturer Asthmatx Inc. that is enrolling at least 300 severe
asthmatics. Some will get thermoplasty and some a sham procedure -
the bronchoscope snaked into their lungs but not heated.

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, cautions Dr. Michael Silver of
Chicago's Rush University Medical Center, who is monitoring the
research and describes himself as "just this side of 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, stresses 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."

Indeed, "I didn't really feel like I had a lot to lose," says Rod
Bailey, 59, of Leicester, England. He wheezed and gasped daily despite
six medications before undergoing thermoplasty two years ago.

The first procedure triggered a bad asthma attack - but he says he
hasn't had one since. Bailey calls his asthma so improved that he cut
his steroid inhaler use by half and is about to go whitewater kayaking.

"It's given me my life back," he says.

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EDITOR'S NOTE - Lauran Neergaard covers health and medical issues for
The Associated Press in Washington.

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On the Net:

Trial info:

www.clinicaltrials.gov/ct/show/NCT00231114?order1

URL:
http://sfgate.com/cgi-bin/article.cgi?file=/n/a/2006/05/22/national/w132339D09.DTL