Recommendations on the management of pulmonary hypertension in clinical practice.

Definition of terms Pulmonary hypertension is defined as a mean pulmonary artery pressure > 25 mm Hg at rest or 30 mm Hg with exercise. The classification of pulmonary hypertension is linked to the anatomy or the aetiology. These diagnostic categories are for the convenience of deciding on treatment. Primary pulmonary hypertension refers to pulmonary hypertension for which no cause can be identified. The term remains unchanged from the previous system of classification. Primary pulmonary hypertension is a form of pulmonary arterial hypertension which also includes collagen vascular disease*, congenital systemic to pulmonary shunts*, portal hypertension*, HIV infection*, exposure to various drugs or toxins*, and persistent pulmonary hypertension of the newborn*. Other types of pulmonary hypertension include pulmonary venous hypertension*, pulmonary hypertension associated with disorders of the respiratory system and/or hypoxaemia*, pulmonary hypertension caused by chronic thrombotic and/or embolic disease*, and miscellaneous causes*. *These hitherto have been called secondary pulmonary hypertension, a term without value for diagnosis and decisions on treatment.