Mario Castro, M.D., a pulmonologist at Washington University School of Medicine in St. Louis, Mo., talks about a surgical procedure that's offering relief to asthma patients who don't respond well to medication.
Which asthma patients are candidates for this new treatment?
Dr. Mario Castro: Bronchial thermoplasty is for patients that have severe asthma. That represents about 10 percent of the population of patients out there with asthma.
Why is there a need for this treatment?
Dr. Castro: Severe asthma patients are receiving the best treatment we have available today, but despite that, they're still having disabling symptoms. They're having continuous shortness of breathing, coughing, chest tightness, wheezing. They're experiencing these symptoms throughout the day and even at night; they're awakening often as well.
What are the current treatments for severe asthma?
Dr. Castro: The current therapy that we have for the treatment of severe asthma includes medications that are used through an inhaler. The types of medications for use are inhaled steroids and bronchodilators. The steroids decrease the inflammation inside your windpipes. The other type of medication that we use is called a bronchodilator. The bronchodilator opens up your windpipes so you can breathe easier, and it works very
quickly. Our patients that have severe asthma use these two types of medications to control their disease and to be able to function better. But despite using these medications, even at high doses, often these patients are quite disabled.
How does the new treatment work?
Dr. Castro: The new treatment is called Bronchial Thermoplasty using the Alair® system. The thermoplasty means that we are providing heat to the windpipes, to the lining of your windpipes, that you breathe air through into your lungs. By applying that heat through a procedure we call the bronchoscopy, we're able to decrease the smooth muscle that's around your windpipes.
What happens when you have an asthma attack is that that muscle constricts. It actually tightens down, so you're trying to breathe through a very tight, narrow opening. What we're trying to do is decrease that smooth muscle that's surrounding the windpipe with this treatment, which is long lasting. In fact, there have been some patients that have been treated over five years ago with this treatment, and the effects of that have been long
lasting for those patients.
How is Bronchial Thermoplasty different than other treatments?
Dr. Castro: The way it treats the muscle is really why it works so differently. The medications that I mentioned earlier – the bronchodilators – those medications work in your windpipe. They help relax the smooth muscle. However, they only last for about four to six hours, whereas this is a permanent treatment where we actually alter the smooth muscle; we decrease the muscle that's surrounding the windpipe. It's a long lasting and effective treatment for these patients.
How is the Bronchial Thermoplasty delivered to the patient?
Dr. Castro: The Bronchial Thermoplasty is actually delivered through an Alair® catheter, a very small skinny catheter that goes through an instrument called a bronchoscope. The bronchoscope is a flexible instrument that we use very often as lung doctors to go down into your windpipes and get access to your lungs to do various treatments. The bronchoscopy procedure itself for this treatment takes about 30 to 45 minutes to accomplish. We do the thermoplasty in a series of three treatments. We try to span a recovery period in between the treatments of about two to three weeks. In total, most patients will require six to nine weeks in order to get all three treatments accomplished.
With the first treatment, we'll go down into your right lower lung or treat the entire right lower lung. We'll stop there and let the patient recover. The second treatment will go over to the left side – we'll treat the left lower lung. The last treatment will treat the upper lungs on both sides.
Who is the best candidate for this procedure?
Dr. Castro: The optimal candidate for this procedure is really somebody with severe asthma that is seeing an asthma specialist, lung doctor or allergist, and despite optimizing the treatment as much as possible, they're still not getting control of their asthma, they're still having very frequent asthma symptoms. They may be having hospitalizations, emergency room visits due to their asthma not being controlled. Those are the type of
patients that really would benefit from this type of procedure.
The patients that we don't think would benefit from this would be patients that really have mild-moderate asthma or those that have primarily exercise induced asthma. For those patients, the medications that we have currently are really good at controlling their asthma. This would not be a treatment that you would like to offer to somebody that really has mild asthma.
What kind of results have you seen in patients?
Dr. Castro: We have quite a bit of experience now with the procedure and following these patients after a long period of time, and really that is what's convinced us is that it's really made a marked difference for some of these patients. We've had patients that have been disabled and they were not able to work and now have been able to return to their work and lead a much more normal life. Once we see what the outcome of this treatment is for that particular patient, it really indicates to us bronchial thermoplasty offers a breakthrough in what we have to offer our patients with severe asthma.
What are the potential side effects to the treatment?
Dr. Castro: When we discuss this with a patient, one of the first things I do is make sure they're aware of what the treatment is and exactly why it's indicated for them. We balance that with explaining what risks are involved in the procedure and what the adverse effects are related to the treatment itself. With bronchial thermoplasty, what we're doing is we're heating the inside of the airway, the lining there, and that actually does induce a mild asthma attack in most patients.
That mild asthma attack lasts for about 24 hours after the procedure, on average. Some patients, it will linger on for a few days, up to about a week, and that's why we allow you a recovery time of about two weeks in between treatments. We've had some patients where the treatment has exacerbated their asthma enough that they needed to come into the hospital to be observed.
We clearly want to discuss that with our patients ahead of time so they're aware of that short-term risk. You then have to balance that with the benefits from the procedure and decide what's right for you. It's not right for everybody because if you are really well controlled and the medications are working for you, you don't really want to go through that additional risk of the procedure. We ask the appropriate patient with severe asthma that things are just not being controlled for them, 'Are you willing to take this risk in order to achieve this long term benefit?'
Is Bronchial Thermoplasty a cure for asthma?
Dr. Castro: This is not a cure for asthma. This is a treatment that we believe benefits those patients with severe asthma uncontrolled with current medications. The reason bronchial thermoplasty is not a cure is that asthma is not just a problem of the smooth muscle – it's also a problem of inflammation in your windpipes and the allergies that are
contributing to that we can only treat the smooth muscle part with Bronchial Thermoplasty. The symptoms that are related to that will be improved, but we can't cure it all together.
When will this treatment be available?
Dr. Castro: The FDA is currently reviewing all the material that's been done, including a large study of bronchial thermoplasty (AIR2) that was just completed. The hope is that the FDA will have completed their review of it and have made a decision by the end of the years, so that we can offer this new promising therapy to our patients with severe asthma by early next year.