A Clinical Study of Inhaled Nitric Oxide in Moderate-to-Severe Chronic Obstructive Pulmonary Disease

Inclusion Criteria: 1. Age ≥ 40 years, ≤ 75 years; 2. Previous smoking history ≥ 10 pack-years, and had stopped smoking for one month before study entry; 3. Met the diagnosis criteria of moderate and severe COPD: a post-bronchodilator FEV1/FVC \< 0.7, and 30%\< FEV1 \< 80% predicted; 4. Signed informed consent and performed all the study mandated procedures. Exclusion Criteria: 1. Pregnant or lactating women; 2. Current or recent month user of nicotine-like substances (including nicotine patches, etc.); 3. A diagnosis of asthma or other non-COPD respiratory disease, in the opinion of the Investigator; 4. Lack of patency of nares upon physical examination; 5. Experienced during the last month an exacerbation requiring start of or increase in systemic oral corticosteroid therapy; 6. Left ventricular systolic dysfunction: left ventricular ejection fraction (LVEF) \< 50%; 7. Clinically significant valvular heart disease, including aortic valvular disease (moderate or severe aortic stenosis or regurgitation) and/or mitral valve disease (moderate or severe mitral stenosis or regurgitation), or status post mitral valve replacement; 8. Use within 30 days of screening or current use of approved pulmonary hypertension medications such as sildenafil, bosentan or prostacyclines; 9. Use of investigational drugs or devices within 30 days prior to enrollment into the study; 10. Any underlying medical or psychiatric condition that, in the opinion of the Investigator, makes the subject an unsuitable candidate for the study.