Endobronchial Valves Address Root Cause of Emphysema Symptoms

Endobronchial Valves Address Root Cause of Emphysema Symptoms
Catheter-placed devices dramatically reduce lung volume, relieving diaphragm pressure.

Many patients with advanced emphysema symptoms, for whom medical management provides insufficient relief, breathe more freely and can resume performing daily activities when they are treated with implantable valves that relieve hyperinflation. Minimally invasive treatment with these endobronchial valves represents an entirely new way to deal with this extremely common, extremely burdensome disease.

While an earlier analysis had followed patients treated with the Zephyr® valves out to 12 months, the most recent study involving the valves, conducted this year, followed patients out to 24 months.

“With Zephyr valves in place, the hyperinflated area shrinks to a fraction of its previous size, relieving the pressure on the diaphragm that had caused the shortness of breath,” said Robert Lentz, M.D., an assistant professor of medicine in the Division of Allergy, Pulmonary and Critical Care Medicine at Vanderbilt University Medical Center. “In patients who responded well to the devices, there were sustained improvements in PFT (pulmonary function test) values, symptoms scores and functional status.”

Addressing Air Trapping

Vanderbilt participated in the initial research that led to FDA approval of emphysema treatment by means of implantable valves, and in several other studies of the valves.

“With Zephyr valves in place, the hyperinflated area shrinks to a fraction of its previous size, relieving the pressure on the diaphragm that had caused the shortness of breath.”

“For years, there wasn’t much we could do to address the underlying mechanical problem of air trapping, which occurs when patients are unable to exhale like they used to and damaged lungs hold too much air,” he said.

Inhalers, which offer some relief to patients with more mild emphysema symptoms, are often insufficient for patients who trap air in more advanced disease, Lentz explained. For them, pulmonologists have relied on either lung volume reduction surgery or lung transplant, both of which are major surgical procedures.

Weighing the Options

“A transplant involves trading emphysema for the disease of being a lung transplant recipient. Recipients require daily immunosuppressants to maintain their transplant which places them at risk for things like infection,” Lentz said. Only slightly more than half of lung transplant patients survive for at least five years after the procedure.

“Lung volume reduction surgery actually does confer a mortality benefit for patients with advanced emphysema. Those who go through it generally do feel better.” However, he added, qualifying for the operation demands satisfying a long list of criteria, which many patients do not meet. Moreover, many prospective patients are so concerned about the surgical risks that few of them accept the operation and few U.S. surgeons offer it, Lentz said.

“While the valves don’t cure emphysema, for those who respond well, we find folks who are able to walk to the mailbox and back or go fishing for the first time in years.”

The selection criteria for bronchoscopic lung volume reduction with Zephyr valves are less stringent, although not all patients considered for the valves qualify. For every four patients evaluated, about one is suitable. Lentz says more than 130 patients have now been evaluated for Zephyr valve treatment at Vanderbilt, and about a quarter of them have received it.

A First: Endobronchial Approach

In the Zephyr procedure, the clinician implants the valves using general anesthesia, a standard bronchoscope and a flexible delivery catheter to guide each valve into the desired airways of the target lobe. Several valves are implanted to ensure the complete blockage of all airways leading to that lobe. The devices can be removed and replaced, if necessary.

“Trapped air in the treated lung escapes through the one-way valve. Eventually the lung’s volume shrinks, relieving pressure on the diaphragm and the patient’s sensation of air trapping,” Lentz said. Breathing mechanics and overall lung function improve, he added. Patients with implanted valves can still be transplant candidates later if they continue to worsen.

Making Life More Enjoyable

“While the valves don’t cure emphysema, for those who respond well, we find folks who are able to walk to the mailbox and back or go fishing for the first time in years,” Lentz said. Patients report these kinds of improvements meaning a lot to them, he said.

Lentz and colleagues continue to explore other treatments for patients with advanced emphysema as well. “We’re excited about what this procedure offers the right patient,” he said. “We’re also continuing to work on other technologies that may help those who aren’t candidates for this one.”