Emphysema patients whose lungs are implanted with a pencil eraser-sized, one-way endobronchial valve experience significantly improved measures of lung function and report better quality of life, University of Pittsburgh School of Medicine researcher Frank C. Sciurba, M.D., reported at Chest 2007, the annual meeting of the American College of Chest Physicians.
"Normally, lungs easily expand and contract with breathing. But with emphysema, air sacs in the lungs lose elasticity and become hyper-inflated, resulting in decreased function and a feeling of breathlessness," said Dr. Sciurba, principal investigator of the multi-center trial, known as the Endobronchial Valve for Emphysema Palliation Trial (VENT) and director of the Emphysema Research Center at the University of Pittsburgh. "Endobronchial valves can allow these over-distended, diseased portions of lung to deflate, improving overall function."
The 31-center, two-year study ended in April 2006 and involved 321 patients in the United States. In the trial, emphysema patients were randomly assigned to either a treatment or control group. Lung function was re-evaluated at six months using a common clinical measure of the volume of air forcibly exhaled in one second (FEV-1) and a six-minute walk test, said Dr. Sciurba. Of the 220 patients who received valve implants, there was a 6.4 percent greater improvement in FEV-1, and a 5.7 percent improvement in distance walked, compared to controls, he said. For some important subsets of treated patients, the results were even more dramatic, Dr. Sciurba added.
"For example, patients who had a fissure completely separating the lobes of the lung and whose endobronchial valves were placed to exclude the entire diseased lobe had changes in FEV-1 of greater than 20 percent," he said. "This is akin to the results achieved in unilateral lung-volume reduction surgery, without the risks of major surgery. Lessons learned in this trial can lead us to more effective targeting of regions in the lung that could provide an even greater response."
Most patients required implantation of three to five valves to isolate the most damaged sections of their lungs. Computed tomography (CT) scanning confirmed significant reduction in size of the lung region where valves were placed, particularly among the subsets of patients with the most favorable responses.
Emphysema is the most common cause of respiratory-related death and the fourth most common cause of death overall in the United States. There are an estimated 1.8 million people in the U.S. who have emphysema, a disease heavily related to smoking.
Treated patients had a slightly higher risk of pneumonia. Most complications resolved within eight days of the procedure, and included shortness of breath, chest pain and low oxygen concentration in the bloodstream. Some patients who received valve treatment later had the valves removed for reasons including lack of efficacy or shifting of position. In nearly all cases, valves were easily removed up to a year following insertion.
Endobronchial valve data must be presented to the Food and Drug Administration and the Center for Medicare and Medicaid Services before the treatment becomes widely available to emphysema patients. Currently, the treatment is limited to those who took part in the clinical trial.
The study was supported by Emphasys Medical Inc. of Redwood City, Calif., manufacturer of the endobronchial valves used in the trial. Neither Dr. Sciurba nor the other investigators report any financially relevant relationships with the company.
Materials provided by University of Pittsburgh Schools of the Health Sciences. Note: Content may be edited for style and length.
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