Long-Term Oxygen Therapy Can Reverse the Progression of Pulmonary Hypertension in Patients with Chronic Obstructive Pulmonary Disease

Publisher Website
Google Scholar
Abstract
Patients (16) with severe chronic obstructive pulmonary disease (COPD) (average values at the onset of O2 therapy: FEV1 [forced expiratory volume in 1 s], 891 .+-. 284 ml; PaO2 [partial arterial pressure of oxygen], 50.2 .+-. 6.6 mmHg; PaCO2 [partial arterial pressure of carbon dioxide], 51.0 .+-. 6.4 mmHg) underwent 3 consecutive right heart catheterizations. The 1st was performed 47 .+-. 28 mo. (T0) before the onset of long-term O2 therapy (LTO2). The 2nd was performed just before the onset of LTO2 (T1). The 3rd was performed after 31 .+-. 19 mo. of LTO2 (T2). O2 therapy (15 to 18 h/day) was prescribed on the basis of usual criteria. From T0 to T1, PaO2 decreased from 59.3 .+-. 9.4-50.2 .+-. 6.6 mmHg and mean pulmonary arterial pressure (Ppa) worsened from 23.3 .+-. 6.8-28.0 .+-. 7.4 mmHg (P < 0.005). From T1-T2, PaO2 was stable, whereas Ppa decreased from 28.0 .+-. 7.4-23.9 .+-. 6.6 mmHg (P < 0.05). Pulmonary hypertension improved in 12 of the 16 patients. Before the onset of LTO2 (from T0-T1), there was a yearly increase in Ppa of 1.47 .+-. 2.3 mmHg, whereas during LTO2 a yearly decrease of 2.15 .+-. 4.4 mmHG was observed and the difference between these 2 values was highly significant. The changes in Ppa either from T0-T1 or from T1-T2 were not associated with concomitant changes in cardiac output or pulmonary capillary wedge pressure but were related to changes in pulmonary vascular resistance. LTO2 for 15-18 h/day can reverse the progression of pulmonary hypertension in a high percentage of patients with severe COPD, but that nomalization of Ppa is rarely observed.