Endobronchial Valves Improve Emphysema 'Modestly'

Unilateral lobar treatment with endobronchial valves produces modest improvements in lung function, exercise tolerance, and symptoms in patients with advanced, heterogenous, hyperinflated emphysema, according to a report in the Sept. 23 issue of the New England Journal of Medicine.

However, these benefits come with substantial costs in the months following implantation: more frequent exacerbations of chronic obstructive pulmonary disease (COPD), pneumonia distal to the valves in more than 4% of cases, hemoptysis related to oozing from granulation tissue, and pneumothorax, said Dr. Frank C. Sciurba of the University of Pittsburgh and his associates.

They assessed the safety and efficacy of endobronchial valves, compared with standard medical care, in what they described as the first randomized, prospective, multicenter study of the devices, the Endobronchial Valve for Emphysema Palliation Trial (VENT).

The study involved 321 patients (aged 40-75 years) who were randomly assigned to receive either the unidirectional valves (220 subjects), which block regional inflation while allowing exhalation, or standard medical therapy (101 controls).

The valves are designed to reduce the volume (hyperinflation) of the most severely damaged lobe, allowing expansion of the more viable adjacent lobe.

A mean of 3.8 valves was placed in each patient via bronchoscopy. The valves were placed in only one lung (in the lobar, segmental, or subsegmental bronchi, depending on the patient’s anatomy) to completely isolate the targeted lobe. Moderate sedation was used in 71% of patients and general anesthesia in 29%. The mean duration of the procedure was 34 minutes.

The composite efficacy end point was the percent change in FEV1 and distance achieved in the 6-minute walk test at the 6-month follow-up. The primary safety end point was a composite of six major complications arising within 6 months: death, empyema, massive hemoptysis, pneumonia distal to the valves, pneumothorax or air leak of more than 7 days’ duration, or ventilator-dependent respiratory failure of more than 24 hours’ duration.

Quality of life, exercise capacity, dyspnea, and daily oxygen use also were assessed as secondary end points.

At 6 months, FEV1 increased by 4.3% in the valve group and decreased by 2.5% in control group, for a mean between-group difference of 6.8%. Similarly, distance traveled in the 6-minute walk test increased by 2.5% in the valve group and decreased by 3.2% in the control group, for a mean between-group difference of 5.8%, Dr. Sciurba and his colleagues reported (N. Engl. J. Med. 2010;363:1233-44).

Patients who received the valves also showed modest changes in all secondary end points.

However, the 6-month rate of composite complications was 6.1% in the valve group, compared with 1.2% in the control group. This included six deaths in the valve group and none in the control group. At 1 year, the complication rates were 10.3% and 4.6%, respectively.

The most common adverse event related to valve placement was pneumonia distal to the valve, which developed in 4.2% of patients within 1 year of the procedure. Hemoptysis requiring bronchoscopic inspection was significantly more common in the valve group (approximately 12%) than in controls (0%). Similarly, pneumothorax developed more often in the valve group (5.2%) than in controls (2.4%), as did COPD exacerbations requiring hospitalization (7.9% and 1.1%, respectively).

“In 12 months of follow-up, valves were removed in 31 patients for reasons including retrieval of a migrated valve (in 8 patients), the patient’s request for an unspecified reason (in 7), pneumonia management (in 3), COPD exacerbations (in 2), hemoptysis (in 1), and other reasons (in 7),” the researchers said. In addition, further bronchoscopies were required in 23% of the valve group, compared with only 1% of the control group.

After the trial was completed in 2007, an additional eight patients underwent elective removal of the valves because of adverse events, and three others experienced spontaneous expectoration of a valve, the investigators said.

The VENT study was funded by Emphasys Medical (now Pulmonx) and a grant to Dr. Sciurba from the National Institutes of Health. Dr. Sciurba and several associates reported ties to numerous drug and device manufacturers.