Severe pulmonary hypertension and chronic obstructive pulmonary disease.

RATIONALE Severe pulmonary hypertension occurs occasionally in patients with chronic obstructive pulmonary disease (COPD), but no detailed description of these patients is available. OBJECTIVES To identify and characterize patients with COPD and severe pulmonary hypertension. METHODS Retrospective study of 27 patients with COPD with severe pulmonary hypertension (pulmonary artery mean pressure [Ppa], > or = 40 mm Hg) among 998 patients who underwent right heart catheterization between 1990 and 2002 as part of a workup for chronic respiratory failure during a period of disease stability. RESULTS Of the 27 patients, 16 had another disease capable of causing pulmonary hypertension. The remaining 11 (11 of 998, 1.1%) patients had COPD as the only cause of pulmonary hypertension, with a median Ppa of 48 mm Hg (interquartile range, 46-50). They had an unusual pattern of cardiopulmonary abnormalities with mild to moderate airway obstruction, severe hypoxemia, hypocapnia, and a very low diffusing capacity for carbon monoxide (p < 0.01 compared with a control group of patients with COPD). Exertional dyspnea was more severe (p < 0.01) and survival was shorter (p = 0.0026) than in the control subjects. CONCLUSIONS Severe pulmonary hypertension is uncommon in patients with COPD. When it occurs, another cause must be sought. COPD with severe pulmonary hypertension and no other possible cause shares features with pulmonary vascular diseases, such as idiopathic pulmonary hypertension.