Evolution of pulmonary hypertension in chronic obstructive pulmonary diseases.

The prognostic value of the presence and degree of pulmonary arterial hypertension in chronic obstructive pulmonary diseases has been well established, but the natural history of the course of pulmonary artery mean pressure was relatively obscure until recent years. The first studies showed a modest increase in pulmonary artery mean pressure after an average delay of 3-5 years. More recently, studying a group of 35 patients with chronic bronchitis, most of them exhibiting pulmonary arterial hypertension followed-up for a mean period of 3 years, Schrijen et al. did not observe a significant change in pulmonary artery mean pressure in patients with or without initial pulmonary arterial hypertension; a marked decrease in systemic arterial pressure occurred in one third of the patients. In 1979 studying a series of 85 chronic obstructive pulmonary diseases patients, we noticed that pulmonary artery mean pressure slightly increased in patients with or without initial pulmonary arterial hypertension, but the average increase, after five years, for the group taken as a whole was only 0.6 mmHg/year. When putting together the data of Boushy and North, Schrijen et al. and Weitzenblum et al. which concern a relatively homogeneous group of 163 patients with severe chronic obstructive pulmonary diseases, it appears that changes in pulmonary artery mean pressure, after an average follow-up period of 4 years, were rather small, from 21.4 to 23.6 mmHg (0.5-0.6 mmHg/year). These results have been confirmed by a very recent study of our group concerning 93 chronic obstructive pulmonary diseases with patients followed-up for 5-12 years (mean = 90 months).