When small is better: volume reduction in severe emphysema

Abstract

@ERSpublications What are our options for lung volume reduction treatment in patients with severe emphysema? http://ow.ly/PgQLVSevere emphysema radically diminishes quality of life. The disease is a result of destruction of lung parenchyma and is most commonly associated with cigarette smoke exposure or the congenital absence of α 1 -antitrypsin. The elastic fibres of the lung, which in a healthy state strive to retract the lungs, are particularly affected. The inward force determined by these fibres is balanced by the chest wall, which strives to push outwards. The result is a finely balanced system where only minimal work is needed in quiet breathing. Emphysema results in a loss of elasticity of the lungs, and thus the inward traction, while the outward force of the thorax remains unopposed, resulting in lung hyperinflation. Further, the small airways, that in normal lungs are kept open and wide by the elastic recoil from the lung parenchyma [1, 2], will have predilection for collapse due to the diminished elasticity of emphysema. Thus, even mild exertion may result in dynamic hyperinflation with air trapping adding to the increased work of breathing. In the 1950s it was shown that removal of emphysematous regions of the lung could considerably enhance lung function and quality of life by improving the total elasticity of the lungs [1]. If successful, residual volume is diminished, small airways collapse is reduced, and the chest will be less hyperinflated allowing the respiratory muscles to work more efficiently.Surgical lung volume reduction was extensively studied and its efficacy proven around the millennium shift [3]. It is now rarely performed, probably due to a high incidence of serious and even life-threatening complications. These factors have led to a search for less invasive methods that may potentially achieve the same benefits as surgical lung volume reduction. These methods include installation of endobronchial valves [4][5][6] or lung sealant [7,8] into affected lobes, thermal vapour ablation of selected lobes [9,10] or "coiling" of the worst affected lung regions [11,12]. For valves to be effective, a whole lobe should be targeted, and there must be no collateral ventilation with other lobes [13,14]. The aim is to induce atelectasis of the lobe. Severe complications are rare, but acute pneumothorax and repeated infections are well-documented. One advantage is the reversibility: the valves are easily removed bronchoscopically. Larger studies have shown statistically significant differences, but have failed to show clinically meaningful differences. However, in subgroups with high heterogeneity and complete fissures [4][5][6], and some small series [15,16], the results have been quite good. It is also a well-established method for treating pleuro-pulmonary fistulas [17]. Coiling is used, especially in Germany, and is promising; however, we still await a cost/benefit analysis on a larger multicentre trial. This method is in practice irreversible but is independent of collateral ventilation.In this...