[Diagnosis, course and prognosis of pulmonary arterial hypertension]

Pulmonary arterial hypertension (PAHT) is defined by an increase in mean pulmonary artery pressure above 20 mmHg. Its diagnosis is often easy by cardiac echo-Doppler. Hemodynamic investigation is required in non-echogenic patients or in order to define the type of PAHT: pre- or post-capillary. It is important to determine, on the basis of non-invasive clinical and paraclinical (echocardiography) studies, those patients in whom catheterisation is indicated. PAHT may be due to chronic respiratory disease, left heart disorders, congenital heart disease or follow pulmonary embolism. It is sometimes apparently primary. The prognosis of PAHT depends upon its etiology: when PAHT is secondary to heart disease, it reflects worsening of the causative cardiac problem, which must be corrected. PAHT is a prognostic factor in chronic obstructive lung disease. The course is particularly grave in primary PAHT.