Researchers at St. Joseph’s Healthcare Hamilton are completing an important phase of a study developing and testing a new – some might say a radical – approach to the treatment of patients with moderate to severe asthma.
Canada has one of the highest incidences of the chronic inflammatory airway disease in the world. As many as three million Canadians suffer from asthma. The disease is most common in childhood and occurs in approximately seven to 10 per cent of all children. About 20 children and 500 adults die from asthma each year.
People with asthma have extra sensitive or hyper-responsive airways. The airways react by narrowing and becoming obstructed when they are irritated, making it difficult for air to move in and out. Wheezing, coughing and chest tightness makes it a struggle for asthma sufferers to catch their breath.
Medications are the key treatment; most people with asthma control their symptoms by taking many medications on a daily basis. Now it may be possible to have the condition treated with an outpatient procedure, a surgical way of keeping the airways open, reducing the need for many of those drugs.
Working with Asthmatix (a venture capital company from Mountain View, California), St. Joseph’s Healthcare researchers were the first to examine in humans whether this new technique, bronchial thermoplasty, could be effectively and safely used.
Several years ago Dr. John Miller, Head of the Division of Thoracic Surgery at St. Joseph’s, began limited bronchial thermoplasty procedures in patients who were scheduled to have lung surgery. He explained, “These projects have been evolving over five years as we’ve tried to find a way to bronchoscopically treat emphysema and asthma. Initially we began looking for ways to stiffen airways for emphysema patients with dynamic airway collapse. As we developed the technology, we saw that this particular way of treating the airway had a profound effect on the smooth muscle and not much else. The amount of smooth muscle is significantly reduced by thermoplasty. We recognized that this procedure might therefore be an appropriate treatment for people with asthma.”
Brenda Donahue had to fight for every breath; her emergency inhaler was never far away. “I was reaching for it seven, eight times a day. My co-workers noticed that even during a simple conversation I was often struggling for breath. They could hear me straining for air from a distance.”
The 42-year-old administration case coordinator had tried different medications with uneven results. Her family physician recommended that she enroll in an investigative study of yet another asthma drug. But she refused. Brenda wanted something else. “This new treatment was an opportunity. And not just for me. I’ve seen children fighting for breath and I know how scared their parents are. I know how terrified I get when I can’t get air into my lungs. This procedure promised to be another way to hopefully reduce, if not cure, my asthma.”
One of the common pathways of all patients who have an asthmatic attack is that the smooth muscle contracts and the airway gets smaller and they end up with shortness of breath or a trip to the emergency room. “Bronchial thermoplasty, delivers controlled thermal (radio frequency) energy to the airway walls and reduces the amount of airway smooth muscle thereby altering the ability of the muscle in the airway to contract or narrow the airway,” said Dr. Miller.
Under general or local anesthetic, the device is passed through a standard bronchoscope and positioned in small to medium sized airways. Several airways are treated under direct vision in a half-hour procedure; to fully treat both lungs it usually requires three treatment episodes.
Having found that this novel technique could be performed safely, Dr. Miller, in collaboration with respirologist Dr. Gerard Cox, head of Clinical Service at St. Joseph’s renowned Firestone Institute for Respiratory Health, began investigating bronchial thermoplasty as an effective treatment for asthma when compared to the standard medical treatment.
“Many of the symptoms of asthma are due to narrowing of airways. In asthma, airway narrowing is profoundly influenced by contraction of muscle located in the airway wall. There is circular muscle around the airway, so that as it contracts the airway gets smaller,” says Dr. Cox. “Bronchial thermoplasty interrupts that ring of muscle so that it is incomplete and thereby decreases the constriction of the airways, and this may be of great benefit in potentially reducing the frequency and severity of asthma attacks.”
Ms. Donahue recalls the procedure as easy to undergo. “I underwent three separate procedures and I think it’s awesome. My treatment by staff at St. Joseph’s Healthcare was outstanding and I would recommend it to other asthma sufferers.”
The researchers are careful to point out that there is no expectation that this new procedure will cure asthma. However, as this procedure may reduce the severity and frequency of asthma symptoms, bronchial thermoplasty may become one of the many treatments that are available for the management of asthma.
“As we learn more, it will be clearer just where bronchial thermoplasty fits in the spectrum of treatment,” said Dr. Miller. “It’s quite possible that this could have long term, meaningful effect without any significant side-effects. It could be useful for patients with mild disease, and reduce the amount of drugs they take or reduce the limitations of their activities. Or it may be that it is useful for very severe asthmatics in preventing life-threatening attacks. So far, the effect in these patients seems to be quite dramatic.”
Brenda Donahue agrees. “It’s a huge difference. My life is so much easier. I still use my inhaler occasionally, but now it’s only a few times a week. I love to walk but couldn’t enjoy it before the procedure. Since the treatment, I can walk longer and farther.”
Drs. Miller and Cox have taken the lead in these projects in which St. Joseph’s Healthcare has been the coordinating centre for several studies that involve 11 sites internationally. The results of the recent studies could be ready for reporting by the fall 2005.
“It is exciting to lead a project such as this, which began with a radical idea, and as a result of careful preparatory research, grew to become the topic of a major international research effort,” said Dr. Cox.