In late stage chronic obstructive pulmonary disease, emphysema can worsen respiratory symptoms not only via the loss of surface for gas exchange but also via alterations in mechanical properties of the respiratory system (dynamic and static hyper-inflation). Emphysematous lung volume reduction aims at improving respiratory mechanics and symptomatology in patients with advanced emphysema. Lung volume reduction surgery (LVRS) has been shown to be effective in selected patient populations but its morbidity and costs are quite elevated. Alternatives to LVRS do not remove emphysematous lung tissue per say but rather consist of devices aiming to: 1) reduce the volume that affected lung parenchyma occupies (unidirectional endobronchial valves or plugs, parenchymal injection of bioactive scarring agents); 2) redistribute ventilatory flow (airway bypass systems). Preliminary studies of these devices have shown that they are relatively safe. These also show modest benefit in exercise capacity, although individual subjects can experience spectacular improvement. Current objective is to identify predictors of response to therapy with such devices.