A 63-year-old woman with advanced COPD is referred because of worsening shortness of breath. She gets short of breath and must stop after walking approximately 367 ft (110 m). She has a prior 60 pack-year smoking history but has been a nonsmoker for 4 years. She has been hospitalized on 2 occasions for acute exacerbation of COPD but has no other significant comorbid conditions. Her vaccinations are up-to-date. She is adherent to her medications, which include an inhaled long-acting muscarinic antagonist and a combination inhaled corticosteroid/long-acting β₂-agonist, as well as albuterol as needed.

Physical examination is consistent with advanced COPD. A chest radiograph demonstrates striking vascular deficiency and hyperlucency, with no masses, adenopathy, or effusions. Pulmonary function testing reveals FEV₁ of 0.73 L (29% predicted), FEV₁/FVC of 0.36, residual volume of 3.97 L (180% predicted), and DLCO of 8.9 mL/minute/mm Hg (40% predicted). The patient might benefit from endobronchial valve insertion. Before proceeding with further investigations, the patient asks for more information.