Paediatric pulmonary arterial hypertension following congenital heart defect repair: enhanced risk stratification and outcomes in a national cohort

Pulmonary arterial hypertension (PAH) is a common complication of congenital heart disease (CHD). PAH following CHD repair (repaired PAH-CHD) is an emerging population with increased morbidity and mortality. Existing PAH risk scores are unvalidated in young children with this condition.

A 20-year cohort from the UK National Paediatric PH Service was studied to describe peri-operative characteristics and outcomes in children with repaired PAH-CHD and to create a tailored risk stratification tool. This tool was externally validated using the national Spanish PH (REHIPED) registry. The study included 178 patients (median age 3.2 years, 58.4% female), with 73.0% referred post-CHD repair. Complex CHD was present in 61.2%, and 48.9% had both pre- and post-tricuspid shunts. Down syndrome was noted in 33.1%. At initial post-operative assessment, 53.1% exhibited symptoms like breathlessness, 30.9% had moderate–severe right ventricular dilatation, and 23.7% showed right ventricular systolic impairment. During a median six-year follow-up of 156 patients, 19.2% died and 3.2% required lung transplantation, with survival rates at one, five, and ten years being 94.7%, 85.9%, and 80.1%, respectively. The developed risk score, based on clinical variables including absence of pre-operative PH, breathlessness, right ventricular dysfunction, and pulmonary vascular resistance index, showed good performance and calibration in predicting outcomes.

In this national cohort of children with repaired PAH-CHD, mortality is significant. This novel, simple risk score has been developed and validated specifically for children with repaired PAH-CHD, useful at the time of post-operative assessment to predict outcome and direct management.