Pulmonary hypertension and cor pulmonale are important predictors of mortality in chronic obstructive pulmonary dis-

DOI: 10.1164/rccm.2107027 Internet address: www.atsjournals.org In 120 patients with severe emphysema evaluated for participation in the National Emphysema Treatment Trial, pulmonary hemodynamics and ventricular function were assessed. Pulmonary function tests were (%predicted): FEV 1 27%; residual volume 224.6%; diffusion capacity 26.7%. In 90.8% of patients, endexpiratory pulmonary artery mean pressure was 20 mm Hg; in 61.4%, end-expiratory wedge pressure was 12 mm Hg. Cardiac index was normal. Mean pulmonary artery pressure correlated inversely with arterial P O 2 , and severity of emphysema, and directly with wedge pressure. Multiple stepwise regression revealed that arterial P O 2 was not an independent predictor of mean pulmonary artery pressure. No correlation was found between indices of emphysema severity and PA pressures. Diastolic ventricular pressures were increased without evidence of systolic dysfunction. We conclude that ( 1 ) elevations of pulmonary vascular pressures are common, ( 2 ) pulmonary hypertension may be related to factors other than hypoxia, ( 3 ) pulmonary hypertension does not impair resting systemic O 2 delivery, and ( 4 ) elevated cardiac diastolic pressures do not represent systolic dysfunction.