Patients with severe emphysema who had one-way valves placed through a bronchoscope into airways leading to diseased areas of their lung experienced improved lung function, exercise tolerance and quality of life one year after the procedure, according to new research published online in the American Journal of Respiratory and Critical Care Medicine.
In “A Multicenter Randomized Control Trial of Zephyr® Endobronchial Valve Treatment in Heterogeneous Emphysema (LIBERATE),” Gerard J. Criner, MD, and coauthors write that the endobronchial valves (EBVs), which allow air to leave but not enter diseased parts of the lung, are effective in reducing the lung hyperinflation that occurs with emphysema and mimic the results of lung volume reduction achieved through major surgery.
“Less invasive methods to reduce lung volume, such as the Zephyr® endobronchial valve, have the potential to improve patient’s symptoms and functional status with fewer complications than lung volume reduction surgery (LVRS),” said Dr. Criner, founding chair and professor in the Department of Thoracic Medicine and Surgery at Temple University’s Lewis Katz School of Medicine in Philadelphia, Pennsylvania. “The FDA has not yet approved any bronchoscopic interventions, so EBVs are not an option for clinical care in U.S. patients at this time.”
Like the current study, previous studies found severe emphysema patients treated with EBVs experienced the same health and quality of life benefits at six months. Dr. Criner said it was important to show that the benefits of EBVs were “durable” and similar to those achieved with LVRS.
The 190 patients (ages 40 to 75) participating in the international study all had severe, heterogeneous emphysema, which is characterized by specific, isolated areas of the lung that expand disproportionately, restricting the ventilation of healthier areas. Participants’ lungs also showed little or no collateral ventilation (bypasses of normal airways) in the areas of the lung targeted for treatment. Twice as many participants were randomized to receive EBVs as to receive standard of care.
At 12 months, the study found:
- 47.7 percent of those with EBVs experienced an improvement in FEV1 (the amount of air that can be forcefully exhaled in one second) of 15 percent or more, compared to 16.8 percent receiving standard of care.
- Residual volume, a measure of hyperinflation, was 522 milliliters less in those with EBVs than in those receiving standard of care.
- Those with EBVs could walk 39 meters farther than those receiving standard of care during a six-minute walk distance test.
- Those with EBVs reported reduced impact–7 points on a scale of 100–of the disease and its symptoms on their functional ability and well-being, as measured by the St. George’s Respiratory Questionnaire.
All these differences, the authors write, were statistically and clinically significant. They also note “a strong signal” that EBVs reduced respiratory failure and COPD exacerbations requiring hospitalizations. Reductions in these events are especially important to show that the long-term benefits of EBVs are comparable to LVRS, Dr. Criner said.
Pneumothorax, or a collapsed lung, was the most common serious adverse event occurring within 45 days of EBV treatment, affecting 26.6 percent of participants in the intervention arm. Four patients receiving EBVs died within the 45 days, compared to none receiving standard of care. Three of the four deaths were due to pneumothorax; one was due to respiratory failure. All were considered “definitely” or “probably” related to treatment.
The authors note that compared to LVRS, patients with EBVs are less likely to suffer a pneumothorax requiring a chest tube, pneumonia and other complications. The only other option for these patients, they add, is lung transplantation, which is limited by eligibility criteria and available organs.
“With this highly symptomatic patient group, the risks of any therapy have to be considered when assessing the benefits,” Dr. Criner said. ”In carefully selected patients, Zephyr EBV treatment provides clinically meaningful benefits comparable to LVRS, but with less post-procedure morbidity.”
This study was sponsored and funded by Pulmonx Corporation, of Redwood City, California, manufacturer of the Zephyr® Endobronchial Valve.