Expanding the Techniques and Indications for Bronchoscopic Lung Volume Reduction

Patients with emphysema frequently complain of exertional dyspnoea despite maximal medical therapy. Destruction of the elastic tissue of the lung leads to enlargement of airspaces, small airway collapse, and progressive hyperinflation. This results in impaired respiratory mechanics and reduced inspiratory capacity, which together cause worsening dyspnoea and impaired exercise tolerance. Lung volume reduction surgery has been shown to improve lung function and exercise capacity in selected patients with upper lobe predominant emphysema by removing the most hyperexpanded areas of lung. However, there is a 5% mortality and considerable morbidity. Several bronchoscopic lung volume reduction procedures have been developed In order to achieve similar results without surgery. This thesis brings together a number of trials of novel devices or techniques designed to achieve volume reduction whilst reducing the risk of significant morbidity or death. Investigations of new treatment strategies and indications for the one-way endobronchial valves are presented, and the problems of collateral ventilation explored. Studies of bilateral incomplete lobar exclusion (no benefit seen in any measured parameter) and subsequent complete unilateral lobar occlusion (marked benefit in selected patients) are presented, together with a clinical review of single lung transplant patients with native lung hyperinflation with findings showing a range of patient responses and suggesting a larger prospective study should be undertaken. Techniques designed to either act independently of, or take advantage of, collateral ventilation are then investigated, with one novel approach being the use of autologous blood to achieve volume reduction. This technique uses no foreign implants, and could deliver dramatic cost savings. Overall short-term results presented here in patients with heterogenous emphysema are disappointing, but a potential signal for longer-term benefit is identified. Accessory airways allow venting trapped gas via non-collapsible artificial airways, using collateral ventilation to achieve whole lung deflation. Immediate results are dramatic, but the benefits are short lived with no difference in end-points between real and sham treatments, and attention to device design is needed. The most promising technique investigated in this thesis is the use of lung volume reduction coils, designed to achieve lung volume reduction by improving the elastic recoil forces of the lung, splinting open small collapsible airways, and improving lung mechanics. Significant improvements in lung function, exercise tolerance, and symptom scores over and above best medical care were seen at 3 months post-procedure with an acceptable safety profile, and longer term results are awaited.Imperial Users Onl