Vol. 19 •Issue 18 • Page 22
New Asthma Treatment Ahead?
Bronchial Thermoplasty in Clinical Trials
Imagine going to the emergency room with a severe laceration that requires immediate attention to keep you from bleeding to death. Imagine the only means to stop the bleeding is to cauterize the wound with a red hot poker.
This is an effective and historically proven method to stop bleeding and has been used in medical emergencies since the earliest days of recorded history when severe wounds received from a sharp object were common. Think of sword wounds from the medieval period, for example, or bayonet wounds during the Civil War.
Medicine was my choice of profession long ago because it offered an unlimited learning curve. I knew that mind-boggling advances designed to stimulate my brain and satisfy my energy level would provide plenty of opportunities and challenges throughout my career.
I have yet to be disappointed, especially when the challenge is something like treating a child in the midst of an asthma attack.
Asthma in the medical community is almost as common a word as “the” in the English language. Despite that, the disease is often underrated and ignored by the public at large. Nonetheless, researchers are actively involved in efforts to relieve the potentially lethal effects of the common asthma attack.
One such effort centers on a procedure called bronchial thermoplasty. An acute asthma attack is characterized by the contraction of the smooth muscle in the airway wall. Bronchial thermoplasty involves a novel bronchoscopic treatment which aims to reduce smooth muscle contraction and to reduce inflammation related to the narrowing of the airways. In asthma research, bronchial thermoplasty is as red-hot as a poker these days.
Harnessing Radio Waves
This technique involves the delivery of controlled therapeutic radio frequency thermal energy through a bronchoscope to apply heat to a section of a smooth muscle ring in the airway, rendering it incomplete. The heat causes the bronchial smooth muscle to scar, preventing the muscle from contracting and closing the airway.
Here in the United States, interventional pulmonolgists at the Hospital of the University of Pennsylvania (HUP) are involved in the application of thermal energy to underlying smooth muscle in the small- to-medium airways using a medical device manufactured by Asthmax Inc. The technology consists of a single-use device hooked to a controller to deliver thermal energy to the lungs.
The procedure can be easily performed in an outpatient setting, not requiring hospitalization.
Smooth muscle in the lungs is reactionary and strategic but expendable. The removal of it increases airway size in both relaxed and contracted states over a normal variation of pulmonary pressures. It’s sort of like widening the pulmonary highway and taking the elastic out of a rubber band simultaneously.
A lot of asthmatics are probably asking themselves whether they should have this new procedure or just continue to take their medication daily. The question is as likely for an asthmatic as is a question for an individual with vision problems who might ask, “Should I risk having my eyes lasered or just wear my glasses?” These are the questions people desperately seeking relief from debilitating disease ask as new options become available.
Little Literature Available
Thus far, the outcomes of 16 patients with mild asthma who have undergone this treatment have been published. The small number of patients showed mild improvement in peak flow and were without asthma symptoms from about a half to three-quarters of a day. Most exhibited short-term side effects like wheezing or a cough after the procedure. The question is whether severe asthmatics will benefit from this procedure in the long term and whether any long-term side effects, if they exist, would be intolerable.
There are legitimate concerns that physically manipulating pre-existing hypersensitive airways is akin to sailing through uncharted waters. Michael Silver, MD, of Chicago’s Rush University Medical Center, is monitoring this research. He remains skeptical and questions whether airways will become too weak to function in the future and whether increased scarring might occur at a later date. Related questions include: How long do the benefits last? Is the procedure worth the risk? And, of course, what is it going to cost? Answers to these questions are either still under study or have not yet been released by the parent company, Asthmax.
However, hope burns eternal in the asthma community, especially when options for treating life threatening diseases are concerned.
In a case study, Rod Bailey, 59, of Leicester, England, said he did not really have anything to lose when he opted for the procedure. Daily wheezing, despite taking six medications daily, led him to undergo thermoplasty two years ago.
“The first procedure triggered a bad asthma attack, but I haven’t had one since,” he noted. His asthma condition has improved to the point where he has cut his steroid inhaler use in half and is about to embark on a white water kayaking adventure.
As therapists, we don’t really need to ask what is the commitment of asthma researchers to the Mr. Baileys of the world. As therapists, we have also seen what asthmatics go through at times to breathe the air many of us take for granted.
Threading through the Lung
The University of Chicago is one of about 30 centers around the world participating in the Thermoplasty Asthma Interventional Research clinical trials. During the procedure, a physician inserts a bronchoscope through the patient’s nose or mouth and works it into the major airways of the lungs. When the bronchoscope is in place, the physician then passes a narrow catheter equipped with an expandable heat source at the tip through the bronchoscope.
The catheter is then expanded to hold it in place and heated for about 10 seconds via radio frequency energy to a temperature approximating that of a cup of coffee. This results in the death of approximately half the smooth muscle cells that line that particular segment of the airway.
The catheter is then repositioned to another place in the airway and reheated. The process takes between 30 and 45 minutes during which heat is applied about 30 times.
Patients participating in the study undergo three separate outpatient visits, allowing for a three-week rest period between sessions.
During the procedures, physicians target small- to medium-size airways at least 3 mm in diameter in different parts of the lung.
I am neither a radio frequency expert nor a ham radio operator, but I do know that in medical studies, the devil is in the details. My curiosity occasionally wanders into the abyss, and frequently some bizarre questions surface from within the deep reaches of my brain.
Here is one I have for this new area of asthma exploration: Has there been any thought given to outside radio wave interference from cell phones, garage door openers and the like when the procedure is underway?
Personally, I would hate to have a catheter running away in my lung because someone is receiving a telephone call in the parking lot. Just a thought.
Michael Donnellan is a California practitioner.