As a single center, it was not possible to recruit enough patients with pulmonary hypertension

Chronic obstructive pulmonary disease (COPD)can be complicated by an increased pressure in the pulmonary circulation. This worsens the prognosis, but so far it is unknown whether treatment of the increased pulmonary blood pressure betters the patients symptoms.

In this study 32 patients with increased pulmonary blood pressure due to COPD will be randomized to 3 months treatment with placebo or sildenafil, which is known to lower the pulmonary blood pressure in other types of pulmonary hypertension.

Our hypothesis is that treatment with sildenafil in these patients will improve the functional capacity measured by the distance walked in 6 minutes and life quality.

Inclusion Criteria:

• A mean pulmonary arterial pressure of 25 mmHg measured by right heart catheterization.
• A diagnosis of COPD-associated pulmonary hypertension, implicating that no other potential cause of pulmonary hypertension is present.
• Stable COPD, defined by no subjective alterations of symptoms or use of short acting beta-antagonists for minimally six weeks. Any exacerbation resulting in admission to hospital or other contacts to a physician must have ceased for at least 6 weeks before entering the study.
• Age > 18
• Informed written consent.
• Reliable anticonception for fertile women.

Exclusion Criteria:

• Rheumatic disease limiting walking capacity.
• Exacerbation in COPD during the study.
• Age>80 years
• FEV1 < 25 % of predicted.
• Allergy towards contents of sildenafil or placebo tablets.
• Fall in blood pressure of > 30 mmHg systolic or >20 mmHg diastolic after intake of the first dose of trial medication.
• Fall in peripheral saturation of > 5% after intake of the first dose of trial medication.
• Treatment with nitrous vasodilators or aminophyllamines.