To explore the mechanism of plasma endothelin-1 (ET-1) level elevation and its relation with pulmonary hypertension in chronic cor pulmonale, plasma ET-1 level was measured by using radioimmunoassay in 21 cases of chronic cor pulmonale with acute exacerbation and cardiac catheterization was performed simultaneously. Results, Peripheral venous plasma ET-1 level of the patients was significantly higher than that of controls and also higher than that of peripheral arterial and pulmonary arterial plasma ET-1 level of the patients themselves. The plasma ET-1 level of patients had a significant negative correlation with PaO2 and SaO2 and positive correlation with mean pulmonary arterial pressure (PAPM) and pulmonary vascular resistance index (PVRI). 9 of the patients were treated with mechanical ventilation. After ventilation, PaO2 went up notably and plasma ET-1 level decreased remarkably, PAPM and PVRI also reduced simultaneously.
Conclusions: The causes of plasma ET-1 level elevation in cor pulmonale may be as follows, Firstly, pulmonary alveolar hypoxia increases the release of ET-1 in lungs; Secondly, the ability of the lungs to clean ET-1 decreases because of pulmonary abnormality. High level of plasma ET-1 may induce pulmonary hypertension. The level of plasma ET-1 can be lowered by correcting hypoxic status of the patients and the resulting improvement of pulmonary hemodynamics.