Patients with heterogeneous emphysema distribution and little to no collateral ventilation benefit from Zephyr® Endobronchial Valve (EBV)® treatment according to the results of the LIBERATE study (ClinicalTrials.gov Identifier: NCT01796392) published in the American Journal Respiratory and Critical Care Medicine.
With the exception of lung transplantation and bullectomy, only lung volume reduction surgery (LVRS) is an effective intervention for emphysema. However, not all patients can benefit from these procedures. Zephyr® EBVs (Zephyr® EBV®, Pulmonx Corporation) are small duckbill valves that are placed via bronchoscope to occlude an emphysematous lobe. Following EBV insertion, partial or full lobar atelectasis reduces hyperinflation and mimics the more invasive LVRS.
Gerard J. Criner, MD, of the Lewis Katz School of Medicine at Temple University, Department of Thoracic Medicine and Surgery in Philadelphia, Pennsylvania, and colleagues conducted a multicenter controlled trial and randomly assigned 190 patients to either EBV or standard of care (SoC) at 24 sites (128 to EBV and 62 to SoC). The primary end point at 12 months was the difference between EBV and SoC in postbronchodilator forced expiratory volume in 1 second (FEV1) improvement from baseline of ≥15%. Secondary end points included absolute changes in postbronchodilator FEV1, 6-minute walk distance, and St. George’s Respiratory Questionnaire scores.
At 12-months 47.7% of patients who received EBV compared with 16.8% of those in the SoC group had an improvement from baseline in FEV1 ≥15% (P <.001). The absolute between-group difference was 31.0 (P <.001). All secondary outcomes demonstrated statistically significant improvement for EBV over SoC. Furthermore, there was a clinically meaningful difference between the groups for change from baseline to 12 months in the 6-minute walk distance of 39 meters, favoring EBV and indicating functional improvement.
However, significantly more patients in the EBV group (35.2%) experienced serious respiratory adverse events during the 45 days following the procedure than in the SoC group (4.8%). This difference was primarily the result of a higher frequency of pneumothorax in the EBV group; 83% of these events were managed with the placement of a chest tube. Over the long-term, the rate of adverse events was similar in the 2 groups.
The authors concluded by noting that the LIBERATE trial demonstrates improvements over controls to the same degree that is achieved with LVRS, but EBV resulted in less morbidity than LVRS, and the 90-day mortality rate after EBV was lower than after LVRS (3.1% vs 5.0% for these procedures, respectively).
Criner GJ, Sue R, Wright S, et al. A multicenter RCT of Zephyr® Endobronchial Valve treatment in heterogeneous emphysema (LIBERATE) [published online May 22, 2018]. Am J Respir Crit Care Med. doi:10.1164/rccm.201803-0590OC