Abstract
Pulmonary hypertension is a serious complication of several chronic lung diseases (Howard 1985). The increase of the pulmonary arterial blood pressure in chronic lung damage results from the high resistance of pulmonary vessels to blood flow.
Three main factors contribute:1. Encroachment of hypertrophied vascular smooth muscle into the lumen of peripheral pulmonary arteries 2.
Decreased compliance of lung vessels 3. Pulmonary vasoconstriction.
The mechanisms of these changes are complex. Chronic lung diseases cause the uneven distribution of inspired gas within the lungs.
The lung damage and inflammatory reaction influence the morphology and regulation of pulmonary blood vessels directly. The altered reactivity of pulmonary vasculature to the pathogenic stimuli also participate.