Compared with optimal medical therapy alone, patients who also received a valve had a 6.8% relative improvement in forced expiratory volume in 1 second (FEV1) (P=0.005), according to Frank Sciurba, MD, of the University of Pittsburgh, and colleagues.
The valve recipients also extended their six-minute walk distance by 5.8% compared with the controls (P=0.04), the researchers reported in the Sept. 23 issue of the New England Journal of Medicine.
But the benefits were accompanied by an increase in pneumonia, chronic obstructive pulmonary disease (COPD) exacerbations, and hemoptysis.
In an accompanying editorial, Antonio Anzueto, MD, of the University of Texas Health Science Center at San Antonio, noted that the use of medical therapy was not standardized during the study, which hampered interpretation of the findings.
Without such standardization, "it is impossible to fully understand the benefits and potential complications of new treatments," he wrote. "In my opinion, it is premature to recommend the routine use of endobronchial valves in patients with COPD."Endobronchial valves allow air to escape a pulmonary lobe but not enter it, and they have been shown in uncontrolled trials to reverse hyperinflation related to advanced emphysema and improve lung function.
Sciurba and his colleagues aimed to compare the Zephyr endobronchial valve with standard medical therapy in the Endobronchial Valve for Emphysema Palliation Trial (VENT), which randomized patients with advanced emphysema to valve implantation (220 patients) or the control group (101 patients).
Before randomization, all patients underwent six to eight weeks of pulmonary rehabilitation and optimized medical management.
Endobronchial valves were implanted in the lobe with the highest percentage of emphysema and the greatest degree of heterogeneity (the difference in percentage of emphysema between lobes in the treated lung) using a flexible bronchoscope. The researchers administered prophylactic antibiotics after implantation.
The mean number of valves placed per patient was 3.8.
After six months, there was an absolute increase in FEV1 of 1% of the predicted value in the valve group and an absolute decrease of 0.9% in the control group, yielding a 6.8% relative between-group difference. The findings were similar for the six-minute walk test.
There appeared to be greater benefits from valve implantation in patients with greater heterogeneity of emphysema and intact interlobar fissures.
Anzueto noted in his editorial that lung volumes did not change in either group during the study.
"Thus, changes in lung function seen in patients with endobronchial valves may not be due to decreased hyperinflation but to other unknown mechanisms," he wrote.
There were modest improvements in quality of life, dyspnea, incremental exercise response, and supplemental oxygen use in the valve group.
The composite safety endpoint -- including death, empyema, massive hemoptysis, pneumonia distal to valves, pneumothorax or air leak of more than seven days' duration, or ventilator-dependent respiratory failure lasting more than 24 hours -- occurred at a nonsignificantly higher rate in the valve group at six months (6.1% versus 1.2%, P=0.08).
That numerical difference was primarily driven by an increase in pneumonia, which occurred in 4.2% of patients with endobronchial valves by 12 months.
By six months, there were six deaths, all in the valve group. The between-group difference was not statistically significant (P=0.19).
After one year, valves were removed from 31 patients for various reasons, including valve migration, patient's request for an unspecified reason, pneumonia management, placement in the incorrect lobe, COPD exacerbations, hemoptysis, and other reasons.
