primary arterial pulmonary hypertension

Last reviewed 01/2018

Primary pulmonary hypertension is a disease of unknown aetiology.

Primary pulmonary hypertension has an incidence of 1-2/million per year. It is more common in women - the female: male ration is ratio 2.3:1. It occurs most often in the 3rd and 4th decades. Symptoms often develop during pregnancy or soon after the birth of a child.

Primary pulmonary hypertension is associated with precapillary obstruction of the pulmonary vascular bed due to the thickened intima of the small pulmonary arteries and arterioles. Atherosclerotic changes may be found in the larger pulmonary arteries.

Primary pulmonary hypertension is by definition idiopathic and there must be no evidence of chronic cor pulmonale, emphysema, pulmonary fibrosis or kyphoscoliosis. Primary pulmonary hypertension must also be differentiated from raised pulmonary pressure due to liver disease, chronic pulmonary parenchymal disease or persistent obstruction of the upper airway.

Approximately 6-10% of cases of primary pulmonary hypertension are familial and the underlying genetic defect generally involves a mutation in a receptor member of the transforming growth factor-beta family (1).


  1. BHF Factfile (1/2003). Pulmonary Hypertension.