Bronchoscopic Lung Volume Reduction with Valves and Coils. A Network Meta-analysis

Background: Coils and endobronchial valves are the most widely used bronchoscopic lung volume reduction devices in patients with advanced emphysema. However, the choice of each specific device depends on emphysema characteristics (homogeneous vs. heterogeneous) and presence of lobar collateral ventilation (CV). These devices have not been compared in a head-to-head study design.Objectives: To conduct a network comparative meta-analysis studying the effect of valves in patients with heterogeneous emphysema without CV, and to also study the effects of valves and coils in patients with mixed homogeneous and heterogeneous emphysema.Data Sources and Data Extraction: PubMed and Web of Science were searched for potentially includable randomized active comparator trials from inception to January 20, 2020, and data were extracted in the working sheets of Comprehensive Meta-analysis.Synthesis: Network meta-analysis was conducted in R program using package "netmeta."Results: In patients with heterogeneous emphysema without CV, both Spiration and Zephyr valves showed significant increases in forced expiratory volume in 1 second (FEV₁) (0.11 L [95% confidence interval (CI), 0.05 to 0.16] and 0.14 L [0.08 to 0.19], respectively) and in reducing St. Georges Respiratory Questionnaire (SGRQ) scores (-9.32 [-14.18 to -4.45] and -8.14 [-11.94 to -4.35], respectively) as compared with control, with no significant interintervention differences. Only Zephyr valves showed significant improvement (52.3 m [95% CI, 26.53 to 77.93]) in six-minute walk distance (6MWD). Both were ranked as equally efficacious in these patients. In the mixed homogeneous and heterogeneous emphysema group of patients, both Zephyr valves and coils showed significant increases in FEV₁ and 6MWD and reduction in SGRQ, as compared with control. Although there were no significant interintervention differences, the magnitude of improvement in these parameters was highest with Zephyr valves (e.g., 6MWD increased by 56.74 m [23.66 to 89.81] vs. 30.31 m [4.00 to 56.63]) in coils), ranking them first. In both populations, these interventions showed a statistically significant association with procedure-related pneumothorax but not with chronic obstructive pulmonary disease exacerbation.Conclusions: In patients with heterogeneous emphysema without CV, both Zephyr and Spiration valves were equally efficacious in FEV₁ and SGRQ improvement. However, in the mixed patients with homogeneous and heterogeneous emphysema, Zephyr valves show relative superiority over coils especially with respect to improvement in 6MWD.