[Hemostatic system factors and endothelial function in primary pulmonary hypertension]

Primary pulmonary hypertension (PPH) is a rare disorder, usually fatal. Although the cause of the disease is unknown, the vascular endothelium seems to play a key role. It has been proposed that a vascular endothelial dysfunction would provoke pulmonary vasoconstriction, platelet activation and thrombin formation; some of these events have already been proven. The presence of thrombosis in PPH patients has been demonstrated, and it seems to have a relationship with a vascular endothelium-dependent coagulation abnormality. Substances of endothelial cell origin capable of modifying the coagulation mechanisms are: heparan-sulfate, thrombomodulin, protein S, tissue factor pathway inhibitor (TFPI), tissue factor, von Willebrand factor, prostacyclin and endothelial-derived relaxing factor; functional and multimeric-pattern alterations in von Willebrand factor have already been reported in PPH patients.