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

Abstract

Abstract Introduction 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 [1–3]. Risk scores that are widely used in the adult PAH population have not been validated and may not be applicable in young children with repaired PAH-CHD. Purpose To characterize the 20-year cohort of the UK National Paediatric PH Service, focusing on peri-operative characteristics and outcomes of children with repaired PAH-CHD, and develop a tailored risk stratification tool. Methods We included consecutive children presenting to our specialist service between 2001 and 2021 with a diagnosis of repaired PAH-CHD. Patients with univentricular physiology, segmental pulmonary hypertension (PH), and PH primarily due to abnormal development of the pulmonary vasculature were excluded. Univariable Cox regression analysis was performed in children with PAH present ≥3 months after CHD repair, with an outcome of death or transplantation. Time-dependent ROC analysis was used to evaluate the risk model. Results Overall, 178 patients were included (age 3.2 [1.3–7.9] years, 58.4% female). Most children (73.0%) were referred following CHD repair. Complex CHD was present in 61.2%, and 48.9% had combined pre- and post-tricuspid shunts. Down syndrome was present in 33.1%. At the first post-operative PH assessment, 53.1% of patients had symptoms, mainly breathlessness. On echocardiographic evaluation, 30.9% had moderate-severe right ventricular dilatation and 23.7% had right ventricular systolic impairment. Over a median follow-up of 6.0 [2.4–11.0] years, 30 (19.2%) patients died and 5 (3.2%) patients underwent lung transplantation. Transpant-free survival at 1, 5, and 10 years was 94.7% (95% CI: 91.2–98.3%), 85.9% (95% CI: 80.3–91.9%), and 80.1% (95% CI: 73.1–87.7%), respectively. Cox analysis identified several clinical variables associated with death or transplantation, of which the following variables assessed post-repair were used to develop the risk score: absence of pre-operative PH, breathlessness, right ventricular dysfunction, and pulmonary vascular resistance index >14 WU m2 or lesion at high risk of causing PH (Figure 1). This novel, simple risk score performed well (AUC >80% at 1, 3, 5 and 10 years) and was well-calibrated in our cohort (Figure 2, D'Agostino-Nam p=0.76). Conclusions In this national cohort of children with repaired PAH-CHD, mortality is significant. This novel, simple risk score performed well in our population and could be used in clinical practice at the time of post-operative assessment to predict outcome and direct management but requires further validation. Funding Acknowledgement Type of funding sources: None.