[Pulmonary arterial hypertension: medical treatment and surgical indications]

Pulmonary hypertension is characterized by a poor prognosis which, therefore, justifies its treatment. Pulmonary vascular endothelium plays a pivotal role in the underlying mechanisms of different forms of pulmonary hypertension. Various paracrine factors, including nitric oxide, prostacyclin and endothelium-1, are synthesized by the endothelium. Nitric oxide and prostacyclin are powerful vasodilators, which also inhibit vascular smooth muscle proliferation and platelet aggregation. Endothelium-1 is probably one of the most potent vasoconstrictor known to date. The net effect of endothelial dysfunction results in increased vasoconstriction, platelet aggregation and occurrence of thrombosis, whereas vasodilatation is impeded. In primary pulmonary hypertension, acute pulmonary vasodilatation is currently sought using inhaled nitric oxide, oral calcium channel blockers or infused prostacyclin to predict the long-term effects of pulmonary vasodilators which might improve the quality of life and survival in some patients. Similar result could be obtained with anticoagulation. The most common cause of secondary pulmonary hypertension is alveolar hypoxia associated with chronic lung diseases. Long-term oxygen therapy improves survival and partially reverses the development of pulmonary hypertension. In chronic thromboembolic pulmonary hypertension, therapy includes anticoagulation and, in the case of lower limb venous thrombosis, inferior vena cava filtration. On the other hand, selected subsets of patients can undergo thromboendarterectomy. If the latter is contraindicated, lung transplantation is the only remaining curative treatment. However, lung transplantation should only be performed in end-stage diseased patients. Inclusion criteria are similar to those applied for primary pulmonary hypertension. The respective indications of heart-lung, double lung, and single lung transplantation, in primary or chronic thromboembolic pulmonary hypertension, remain to be evaluated.