Endoscopic lung volume reduction with endobronchial valves in very low DLCO patients: results from the German Registry - Lungenemphysemregister e.V

Background: Endoscopic lung volume reduction (ELVR) with valves has been suggested to be the key strategy for patients with severe emphysema and concomitant low diffusing capacity of the lung for carbon monoxide (D-LCO). However, robust evidence is still missing. We therefore aim to compare clinical outcomes in relation to D-LCO for patients treated with ELVR. Methods: We assessed D-LCO at baseline and 3 months follow-up and compared pre- and postprocedural pulmonary function test, quality of life, exercise capacity and adverse events. This is a retrospective subanalysis of prospectively collected data from the German Lung Emphysema Registry. Results: In total, 121 patients treated with ELVR were analysed. Thirty-four patients with a D-LCO 20% showed similar baseline characteristics. After ELVR, there was a decrease of residual volume (both p < 0.001 to baseline) in both groups, and both demonstrated better quality of life (p < 0.01 to baseline). Forced expiratory volume in 1 s (FEV1) improved significantly only in patients with a D-LCO > 20% (p < 0.001 to baseline). Exercise capacity remained almost unchanged in both groups (p = 0.3). The most frequent complication for both groups was a pneumothorax (D-LCO 20%: 16.1%; p = 0.728). However, there were no significant differences in other adverse events between both groups. Conclusions: ELVR improves lung function as well as quality of life in patients with D-LCO > 20% and D-LCO