Endothelial dysfunction in patients with pulmonary hypertension

Endothelial impairment or dysfunction leading to disturbed balance between vasoconstrictor and vasodilator substances can play an important role in pathogenesis of primary pulmonary hypertension. In 22 patients with primary pulmonary hypertension and 14 patients with secondary pulmonary hypertension due to rheumatic mitral stenosis endothelial function was assessed by determination of levels of endothelin-1 and metabolites of prostacyclin and its antagonist of platelet origin thromboxane A(2). Prostacyclin metabolite concentration was substantially decreased irrespective of the etiology of pulmonary hypertension. Levels of endothelin-1 were elevated being significantly higher in patients with primary pulmonary hypertension. Concentration of thromboxane B-2 was increased (compared pared to control) exclusively in patients with primary pulmonary hypertension. Observed elevation of levels of vasoconstrictors (metabolite of thromboxane A(2) and endothelin-1) and lowering of prostacyclin metabolite could lead to constriction of small pulmonary arteries and to remodeling of pulmonary vessels with intimal and medial hypertrophy.