Published: Apr. 17, 2006
Updated: Apr. 18, 2006
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By Duke Medicine News and Communications
DURHAM, N.C. -- An experimental implantable valve designed to create more space for healthier portions of the lung in emphysema patients is being tested by pulmonary specialists across the U.S. and Canada, including Duke University Medical Center. Physicians can implant the "Intra-Bronchial Valve" without an incision, potentially providing a minimally invasive alternative to lung volume reduction surgery, said the Duke researchers. The valve limits airflow to a selected portion of the lung, producing a reduction in lung volume, which may improve pulmonary function in subjects with emphysema, they said. Duke is now enrolling patients for its segment of the clinical trial.
If the minimally invasive approach proves effective in clinical trials, it could alleviate the shortness of breath and improve the quality of life for many of the 16 to 30 million U.S. citizens afflicted with emphysema, said Dr. Momen Wahidi, director of the Interventional Pulmonology Program at Duke and lead investigator on the study.
Emphysema is a chronic lung disease that involves damage to the walls of the air sacs of the lungs. As the air sacs stretch and weaken, they are less able to deflate with each exhalation, trapping air. The lungs become enlarged and less efficient at inhaling air and exhaling contaminants, making breathing difficult. Smoking is the major cause of the disease, but air pollution and other environmental factors can also play a role, said the researchers.
"Patients experience shortness of breath, making it difficult for them to carry on daily activities such as grocery shopping or walking the dog," said Wahidi. "Many patients require oxygen supplementation and can eventually become wheelchair-bound."
Currently, physicians treat emphysema patients with medications that dilate the airways and reduce inflammation; however, this treatment is not effective in many patients. Surgical lung volume reduction is also a possible treatment in emphysema patients in whom damage to the air sacs is more concentrated in the upper portions of the lungs. By surgically removing these upper parts, surgeons can create more dspace for the healthier lower parts. However, adds Dr. Wahidi, not every patient is a candidate for this surgery and there are risks associated with it in sicker patients.
"Instead of surgery, we place a small umbrella-shaped valve, called the Intra-Bronchial Valve, in the bronchial tubes of the most damaged parts of the lungs," said Wahidi. "This allows the more effective parts of the lung to have more space and may improve breathing, replicating what lung volume reduction surgery would do but in a less invasive way."
Since the device is implanted endoscopically -- via a tube inserted into the lung -- patients can be discharged within 24 to 48 hours, Wahidi said. Another advantage of the device is the ability to remove it if no benefits are obtained or complications arise, he said.
To be eligible for the trial, patients must have moderate to severe emphysema and must have abstained from smoking for at least six months.
Duke is one of 10 sites around the country enrolling patients in this study and the only site in North Carolina. Duke was chosen as one of the sites because of the large number of emphysema patients seen at Duke University Medical Center, with treatments ranging from pulmonary rehabilitation to surgical lung volume reduction and lung transplantation, said Dr. Wahidi. He and his co-investigator thoracic surgeon Dr. Thomas D'Amico would like to enroll as many patients as can qualify for the study.
"This study is of special interest to North Carolina because there are so many patients in our state with emphysema," said Wahidi.
The trial is sponsored by the developer of the valve, Spiration, Inc. Neither Dr. Wahidi nor Dr D'Amico has any financial interests in Spiration.