Changing demographics of pulmonary arterial hypertension in congenital heart disease.

Pulmonary arterial hypertension (PAH) is a serious complication of congenital heart disease (CHD). Without early surgical repair, around one-third of paediatric CHD patients develop significant PAH. Recent data from the Netherlands suggest that >4% of adult CHD patients have PAH, with higher rates in those with septal defects. A spectrum of cardiac defects is associated with PAH-CHD, although most cases develop as a consequence of large systemic-to-pulmonary shunts. Eisenmenger's syndrome, characterised by reversed pulmonary-to-systemic (right-to-left) shunt, represents the most advanced form of PAH-CHD and affects as many as 50% of those with PAH and left-to-right shunts. It is associated with the poorest outcome among patients with PAH-CHD. 40 yrs ago, ∼50% of children with CHD requiring intervention died within the first year, and <15% survived to adulthood. Subsequent advances in paediatric cardiology have seen most patients with CHD survive to adulthood, with resulting shifts in the demographics of CHD and PAH-CHD. The number of adults presenting with CHD is increasing and, although mortality is decreasing, morbidity is increasing as older patients are at increased risk of arrhythmia, heart failure, valve regurgitation and PAH. Data show that probability of PAH increases with age in patients with cardiac defects.