Asthma can be treated, safely and effectively, with a procedure that uses electromagnetic energy to alter problematic muscles in the airways, according to promising new Canadian research.
The procedure, known as bronchial thermoplasty, does not cure asthma, nor will it eliminate the ubiquitous inhaler, but it reduces symptoms and lessens the need for drugs to treat the condition.
It is the first non-drug treatment for the common breathing disorder, good news for sufferers who have trouble controlling their symptoms with traditional anti-inflammatory drugs such as steroids.
"We're not saying this is for everyone," Gerard Cox, a respirologist at the Firestone Institute for Respiratory Health of St. Joseph's Healthcare Hamilton in Hamilton, said in an interview.
"But this procedure looks very promising for people with moderate to severe asthma who don't get adequate control of their condition with existing medications."
He noted that research had been done only on adults, and not on children. Most asthma is diagnosed in childhood.
The research, published in Thursday's edition of the New England Journal of Medicine, involved 112 patients, half who underwent the procedure.
Those who did had, on average, 86 additional symptom-free days a year, and nine fewer exacerbations (severe episodes that can result in hospitalization) than patients who were treated with medication alone.
Bronchial thermoplasty patients also required fewer puffs from their bronchodilators and had better scores on a number of tests that measure breathing during the two-year research period.
Brenda Donahue, a 44-year-old administrative assistant from Hamilton, has suffered from severe asthma for 20 years. She underwent bronchial thermoplasty five years ago and says "it's done wonders for me."
"One of my co-workers said it was amazing. She couldn't hear me breathing any more. No more wheezing or rasping."
But the greatest benefit, Ms. Donahue said, was that her asthma stabilized; she went to one puff a day of medication from five, and had fewer exacerbations.
Bronchial thermoplasty is a simple procedure that involves sliding a long, thin tube (a bronchoscope) down the throat and into the airways. At the tip of the wire is a tiny expandable basket that opens up and fits snugly in the airway wall. Once installed, a short burst of radio frequency energy is released that heats up the muscle. The bronchoscope is then moved a bit and more muscle is zapped.
"The heat actually causes mild injury to the muscle and, when it heals, the airway is less able to contract," Dr. Cox said.
The approach is based on evidence that overgrown muscle tissue lining air tubes inside the lungs is one of asthma's underlying causes. The so-called smooth muscle encircles airways and when something irritates the lungs, it provokes muscle spasms, narrowing air passages and leaving patients gasping. Repeated attacks thicken the muscle and make it even more sensitive to asthma triggers.
The procedure, which requires only a mild anesthetic, is repeated three times, with each session lasting 30 to 45 minutes.
Mark Greenwald, an allergist and vice-president of the Asthma Society of Canada, said that, to date, bronchial thermoplasty has only been studied on patients with "severe non-responsive asthma" and is unlikely to become a mainstay of treatment.
But he said the research is important and exciting because "it opens up a whole new avenue for thinking about asthma."
Treatment has long focused on reducing inflammation of airways and controlling muscle spasms with drugs. "The new principle is that you can get a benefit from reducing muscle mass, and that opens up a lot of possibilities," Dr. Greenwald said. He said, eventually, it may be possible to use medications to reduce muscle mass, eliminating the need for bronchial thermoplasty.
An estimated 2.7 million Canadians suffer from asthma. The chronic respiratory condition causes about 500 deaths annually.
