[Anticoagulation in pulmonary arterial hypertension]

In pulmonary arterial hypertension (PAH), thrombosis and thromboembolism occurs as a consequence of pulmonary microvasculopathy with a change of pulmonary vascular microenviroment toward a procoagulant, prothrombotic and antifibrinolytic pattern. Circulating antiphospholipid antibodies, increased plasma levels of platelet aggregating agents (serotonin, thromboxane), adhesion molecules (P selectin, von Willebrand factor), antifibrinolytic enzymes (plasminogen activator inhibitor 1) and prothrombotic cytokines have been identified in PAH patients so far. Thrombogenic pulmonary vasculopathy has been documented in many patients with PAH. Furthermore, most patients will not be diagnosed until right heart enlargement and impaired right ventricular function has developed. Thus, there is clear rationale for a treatment with anticoagulation. In four uncontrolled studies Warfarin improved the prognosis of patients with idiopathic and other forms of PAH. However, so far there are no prospective randomised studies evaluating the role of anticoagulants in the treatment of PAH. This review summarizes the current data and guidelines concerning anticoagulation in PAH.