Assessment of efficacy and safety of endoscopic lung volume reduction with one-way valves in patients with a very low FEV₁

Introduction Endoscopic lung volume reduction (ELVR) with one-way valves produces beneficial outcomes in patients with severe emphysema. Evidence on the efficacy remains unclear in patients with a very low forced expiratory volume in 1 s (FEV 1 ) (≤20% predicted). We aim to compare clinical outcomes of ELVR, in relation to the FEV 1 restriction. Methods All data originated from the German Lung Emphysema Registry (Lungenemphysem Register), which is a prospective multicentric observational study for patients with severe emphysema after lung volume reduction. Two groups were formed at baseline: FEV 1 ≤20% pred and FEV 1 21–45% pred. Pulmonary function tests (FEV 1 , residual volume, partial pressure of carbon dioxide), training capacity (6-min walk distance (6MWD)), quality of life…