Surgery for Asthma?

1823

Researchers at St. Joseph’s Healthcare have revived a theory that has lain dormant for decades. Surgery may have a role to play in helping patients with mild to severe asthma.

The project began three years ago with funding from Broncus Technologies Inc. Building on experience from animal studies, St. Joseph’s Healthcare researchers were the first to examine in humans whether a new technique, bronchial thermoplasty, could be used safely in human airways.

Dr. John Miller, Head of the Division of Thoracic Surgery, carried out limited bronchial thermoplasty in patients who were scheduled to have lung surgery. He explains “bronchial thermoplasty can be compared to micro-surgery, instead of using a knife, heat is delivered to the airway wall which results in damage to the muscle there. A controlled thermal energy of less heat then a hot cup of coffee, is delivered to the airway wall to prevent smooth muscles in the airway from contracting.”

Under general anesthetic, a surgeon inserts a device just below the voice box. Thirty to 40 airways are treated at once, with treatment of the entire airway taking three sessions.

Having found that this novel technique could be used safely to interfere with muscle in the airway wall, Dr. Miller, in collaboration with respirologist Dr. Gerard Cox of St. Joseph’s Firestone Institute for Respiratory Health, undertook a study of bronchial thermoplasty in patients with mild to moderate asthma.

This study “Early Clinical Experience with Bronchial Thermoplasty for the Treatment of Asthma” looked at the safety of performing the new procedure and was conducted at St. Joseph’s Healthcare and at Vancouver General Hospital.

After suffering from asthma for 14 years, Brenda Donohue, 40, underwent the procedure. “It’s incredible. My quality of life is better. I’m now able to go weeks without my puffer and I feel I have more energy.”

The results were recently presented at the annual meeting of the AmericanThoracic Society held in Atlanta.

“The response was fantastic”, says Miller, “this research clearly re-opens an interest in asthma research that has been quiet for several decades. The concept that surgery may have a role to play in the treatment of asthma is exciting great interest.”

Now that it has been established that the new procedure can be carried out safely in people with asthma, Drs. Miller and Cox will move on to the next phase of the investigation which is to examine whether bronchial thermoplasty is an effective treatment for asthma.

“Many of the symptoms of asthma are due to narrowing of the airway which is caused by contraction of the muscle. There is circular muscle around the airway, so that as it contracts the airway gets smaller,” says Miller. “The effect of bronchial thermoplasty, to cut that ring of muscle so that it is incomplete and does not constrict the airway, may be of great benefit in preventing airway narrowing, potentially reducing the frequency and severity of attacks.”

The researchers are careful to point out that there is no expectation that this new procedure will cure asthma. It is expected that this surgical procedure will have an impact on disease processes in a way that reduces the severity and frequency of symptoms. Thus bronchial thermoplasty may become one of the many treatments that are available for the management of asthma.

The new trial will be carried out in a number of sites across Canada and in Europe. Drs. Miller and Cox expect to study 20 patients over the next two years. The study hopes to demonstrate that bronchial thermoplasty is effective as measured by reduced need for medications to control symptoms as well as a reduced frequency of deterioration in asthma control.

“It is exciting to lead a project such as this, which began with a radical idea, and as a result of careful preparatory research, is now the topic of a major international research effort” says Dr. Cox.

St. Joseph’s Healthcare continues to be an international leader in research that spans the frontiers of medicine and surgery. Dr. Miller is the principal investigator of the Canadian Lung Volume Reduction Surgery trial that examines the role of surgery in another common chronic respiratory disease, that is emphysema. He is also a site investigator for another novel approach to emphysema which involves placement of stents to relieve airway obstruction. “St. Joseph’s Healthcare has a group of enthusiastic physicians and surgeons who are interested in carrying out this kind of research”, says Miller, “which are clearly on the leading edge of science”.