Asthma can be difficult to treat, so physicians at the Yale Center for Asthma and Airway Disease (YCAAD) are always searching for novel therapeutic approaches to treat severe cases for which drug treatment has proved ineffective. A case in point is bronchial thermoplasty (BT), a new minimally invasive procedure made possible by a device recently approved by the FDA that uses radiofrequency energy to treat moderate to severe asthma.
Each year thousands of patients visit YCAAD, which recently became the first center between Boston and New Jersey to offer BT. Because YCAAD’s multidisciplinary approach creates an ideal setting for performing and refining the procedure, the center is one of 30 in the country participating in a phase IV post-market trial of the new device.
Asthma symptoms result from an excess of smooth muscle cells in the airways of the lungs. When various triggers cause airway inflammation, bronchial muscle cells contract and constrict the airways, making breathing difficult. In BT, a flexible camera known as a bronchoscope is adapted with the BT device to gently heat and eliminate smooth muscle. This prevents the airways from constricting.
The studies that led to FDA approval of the BT procedure showed that it significantly mitigated asthma symptoms and flare-ups of the disease, improving asthma patients’ quality of life.
“With this breakthrough treatment, we are confident we will be able to alleviate much of the suffering of our patients with severe asthma,” says Geoffrey L. Chupp, M.D., associate professor of medicine and YCAAD director. “In the past, these patients received high doses of medication and continued to suffer from frequent asthma attacks and limitations on routine daily activities, as well as frequent emergency room visits. Bronchial thermoplasty gives new hope to these asthmatic patients and a non-drug option to control their disease.”
Jonathan T. Puchalski, M.D., assistant professor of medicine and director of the Thoracic Interventional Program in the medical school’s Section of Pulmonary and Critical Care Medicine, performs the BT procedure with the help of a team that includes Kimberly Ebel, R.N., Suzanne Koshis, R.N., and Kelsey Johnson, P.A. Patients are sleepy during the procedure but breathing on their own, and they are usually able to go home afterwards.
Because the BT procedure itself can sometimes trigger an asthma attack, it is generally performed in three outpatient sessions in which different regions of the lungs are treated, spaced about three weeks apart.
One patient who was recently treated with the procedure at YCAAD had suffered from severe asthma his entire life. With poor lung function, he was chronically short of breath and had trouble exercising.
Like many patients who undergo BT, this patient’s symptoms worsened for a brief period immediately after the procedure. After four months, however, he had decreased his medications and no longer used a rescue inhaler when playing sports. He has increased his heart rate by 20 points when exercising on a treadmill, and his lung function has also slightly improved.
“This is exactly the clinical response you would predict based on the trials evaluated by the FDA. The patient is pleased he went through the procedure,” says Chupp.
Patients who undergo BT receive follow-up care from a team that includes Nicole Grant, R.A., and Carol Holme, who provide assessment immediately after the procedure, and Radhika Nandlal, R.N., who provides care and advice to BT patients who return to YCAAD over the long term.
As the only major asthma center in the Northeast, YCAAD physicians and scientists enjoy unique opportunities to conduct research aimed at understanding the biological pathways at the root of asthma as well as to improve treatments like BT.
The center maintains a large repository that includes clinical and physiological data, DNA samples, plasma, and lung specimens from asthma patients who are stable or are experiencing flare-ups. All of this data is regularly uploaded into a Web-supported database so that information is readily available, making it easier to recruit patients for clinical trials and identify those who could benefit from specific treatments like BT.
“We’re trying to get better at figuring out what therapy is best for what person,” says Lauren E. Cohn, M.D., assistant professor of internal medicine and YCAAD co-director. “Because we see so many patients with this disease, we really are starting to understand how to group our patients and how to get the sense of who might need BT.”
In 2007, Chupp and Jack Elias, M.D., chair and Waldemar Von Zedtwitz Professor of Medicine, reported in The New England Journal of Medicinethat asthmatic patients have high levels of a protein called YKL-40 that helps regulate the immune response and can cause lung inflammation. They went on to show that those with a particular mutation in the YKL-40 gene are at greater risk of developing asthma and have lower lung function.
Cohn has joined Chupp and Elias in a search for biomarkers that can predict patients’ response to BT. The team believes that the YKL-40 mutation or levels of the protein in the blood may be a good candidate, since YKL-40 levels appear to decrease significantly after BT.
“We customize the treatment approach for every patient and determine if they’re a candidate for BT or some other advanced or investigational treatment,” says Chupp. “YKL-40 might be a clinically useful marker of responsiveness.”
Puchalski believes that BT is a promising treatment for some patients who obtain unsatisfactory results from asthma inhalers or oral medications such as beta-agonists. “This new procedure offers a potential upgrade for treatment over inhaled drugs or other medications because we are attacking the problem at its very root,” he says. Chupp agrees: “For those with severe asthma, this is a terrific option where medication can fall short.”