Pulmonary artery hypertension (PAH) is a rare progressive disease of the pulmonary vasculature. Although it affects fewer than two adults per million population, and probably fewer children, the clinical course can be one of rapid deterioration, with death occurring within three years of diagnosis for adults, and less than one year for children.^1,2 In the last decade, greater understanding of the disease has led to rethinking the diagnostic classification of pulmonary hypertension, and the identification of therapeutic targets for drug development. A number of new drugs have been studied in randomised controlled trials, and are licensed to treat PAH. A key message from the recent World Symposium on Pulmonary Arterial Hypertension was to refer patients to a centre with expertise in managing PAH; however, paediatricians may encounter patients already commenced on these novel drugs and delivery systems.³ This review will summarise the key trials of the new drugs recently marketed for PAH, some of which are not yet available and none of which are licensed for children in the UK.

DIAGNOSTIC CLASSIFICATION AND DEFINITIONS

Until recently, primary pulmonary hypertension (PPH) was the term used to describe familial disease, or sporadic disease of unknown cause. At the World Pulmonary Arterial Hypertension Symposium in 2003, the term “primary pulmonary hypertension” was officially abandoned and replaced with idiopathic pulmonary artery hypertension (IPAH). This term more accurately indicates that the diagnosis is by exclusion, and exact causes are not known. Where genetic information supports a hereditary basis, the term familial pulmonary artery hypertension (FPAH) is to be used. In this classification, pulmonary artery hypertension (PAH) is differentiated from pulmonary hypertension caused by left heart disease; or chronic lung disease or hypoxaemia; or chronic thrombotic or embolic disorders affecting the lungs; or other infectious or inflammatory triggers (table 1). This classification system is useful in that …