Giornale italiano di cardiologia
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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. ⋯ 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).
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Clinical Trial
Effects of oxygen therapy on pulmonary arterial hypertension in chronic obstructive lung disease.
In patients suffering from chronic obstructive lung disease pulmonary arterial hypertension is mainly due to anatomical lesions. For this reason it does not regress following acute administration of oxygen, unlike functional pulmonary arterial hypertension due to vasoconstriction, which superimposes itself on the anatomical lesions during exacerbations of respiratory insufficiency. At present there is convincing proof that protracted treatment with oxygen is able to reduce pulmonary arterial hypertension sustained by anatomical alterations. ⋯ S. (duration of follow-up: 6 months), the other in Great Britain (duration of follow-up: 5 years), have reached this conclusion. The effects of oxygen on pulmonary arterial hypertension are directly proportional to the number of hours in which oxygen is administered daily; in any case this number should not be below 15 hours/day. The reasons for which treatment with oxygen is not able to arrest the evolution of pulmonary arterial hypertension in some patients and the role of the reduction in blood viscosity due to oxygen therapy remain to be clarified.