Behavior of the pulmonary circulation in chronic obstructive pulmonary disease. Pathogenesis of pulmonary arterial hypertension at an attitude of 2,240 meters.
The hemodynamics of the pulmonary circulation were examined in 28 patients with severe and stable chronic obstructive pulmonary disease (COPD) who were born and raised at high altitude (2,240 meters) (COPD-A). All patients had mean pulmonary pressures (PAP) greater than 16 mmHg. We observed: (1) a low correlation between pulmonary arterial diastolic pressure (PAd) and arterial oxygen saturation (r = 0.38, p less than 0.05); (2) similar PAP in patients with COPD living at sea level (COPD-S) and patients with COPD-A (COPD-S, 32 +/- 7 mmHg; COPD-A, 27.5 +/- 11 mmHg; p = NS), despite more unsaturation in patients with COPD-A (COPD-S, 84.6 +/- 6%; COPD-A, 77.5 +/- 9%; p less than 0.05) and similar arterial pH; (3) lower levels of PAP in COPD-A (COPD-S, 51.7 +/- 10 mmHg; COPD-A, 33.6 +/- 12 mmHg; p less than 0.001) for the same degree of unsaturation (COPD-S, 71 +/- 6%; COPD-A, 71 +/- 8%; p = NS) and a lower arterial pH in COPD-S (COPD-S, 7.34 +/- 0.03; COPD-A, 7.39 +/- 0.04; p less than 0.01). We conclude that pulmonary hypertension caused by chronic alveolar hypoxia is present in COPD-A, but it seems to be decreased when compared with that observed in COPD-S.
D000328:Adult; D000531:Altitude; D002302:Cardiac Output; D006439:Hemodynamics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008176:Lung Volume Measurements; D008875:Middle Aged; D011652:Pulmonary Circulation; D011659:Pulmonary Gas Exchange; D011669:Pulmonary Wedge Pressure