Hypothesis: Patients with advanced emphysema with predominance of the disease in areas other than the upper lobes, as determined by high resolution computed tomography (HRCT), could have a positive response to valve treatment.

Inclusion Criteria:

• Age 18-80 years
• Ex-smoker with smoking cessation confirmed by exhaled carbon monoxide (CO) levels
• Moderate to severe airflow obstruction FEV1 <50% Predicted
• Severe dyspnoea - mMRC ≥2
• Hyperinflation - total lung capacity (TLC) ≥100% predicted, RV ≥150% predicted
• SWT ≥75m
• Optimum COPD treatment for at least 6 weeks
• No COPD exacerbation for at least 6 weeks
• Less than 4 admissions for exacerbation in the preceding 12 months

Exclusion Criteria:

• Patient unable to provide informed consent
• Patient without clear targets for airflow re-distribution
• Total lung CO uptake (TLCO) <15% predicted and FEV1 <15% predicted
• pO2 on air <6.0kPa
• pCO2 on air >8.0kPa
• Neurological, rheumatological or other cause of exercise limitation
• Other major medical illness, e.g. lung cancer that will limit participation
• Production of purulent sputum more often than not (more than 50% of days)
• Clinically significant bronchiectasis
• Large bulla - more than 1/3 of hemithorax volume (i.e. where bullectomy would be more suitable) on CT scan
• Arrhythmia or cardiovascular disease that poses a risk during procedure or exercise
• Prednisolone dose greater than 15mg a day
• Significant pulmonary hypertension - RVSP ≥45mmHg
• Left ventricular failure - left ventricular ejection fraction <45% or left ventricular fraction shortening <23%
• Prior LVRS or lobectomy
• Lung nodule requiring surgery
• Subject completed or is participating in a standard pulmonary rehabilitation program within 3 months of enrolment
• Female of childbearing age with positive pregnancy test
• Subject participated in a research study of investigational drug or device in prior 30 days
• Subject taking clopidogrel, warfarin, or other anticoagulants and unable to abstain for 5 days pre-procedure