Twenty-Year Experience and Outcomes in a National Pediatric Pulmonary Hypertension Service.

Rationale: Pediatric pulmonary hypertension is an important cause of childhood morbidity and mortality, but there are limited data on the range of associated diseases, contributions of different pulmonary hypertension subtypes, therapeutic strategies, and clinical outcomes in children. Objectives: To report the 20-year experience of a large UK National Pediatric Pulmonary Hypertension Service focusing on epidemiology and clinical outcomes. Methods: Consecutive patients presenting between 2001 and 2021 were included, and survival analysis was performed for incident patients. Measurements and Main Results: Of 1,353 patients assessed, a pulmonary hypertension diagnosis was made in 1,101 (81.4%) patients (51% female, median age, 2.6 [interquartile range, 0.8-8.2] years). The most common form was pulmonary arterial hypertension in 48%, followed by 32.3% with pulmonary hypertension due to lung disease. Multiple contributory causes of pulmonary hypertension were common, with 16.9% displaying features of more than one diagnostic group. The annual incidence of childhood pulmonary hypertension was 3.5 (95% confidence interval [CI], 3.3-3.8) per 1 million children, and the prevalence was 18.1 (95% CI, 15.8-20.4) per 1 million. The incidence was highest for pulmonary hypertension due to lung disease in infancy (15.0 [95% CI, 12.7-17.2] per 1 million per year). Overall, 82.4% patients received pulmonary arterial hypertension therapy, and escalation to triple therapy during follow-up was required in 13.1%. In 970 (88.1%) incident patients, transplant-free survival was 86.7% (95% CI, 84.5-89%) at 1 and 68.6% (95% CI, 64.7-72.6%) at 10 years. Pulmonary hypertension due to left heart disease had the lowest survival (hazard ratio, 2.0; 95% CI, 1.36-2.94; P < 0.001). Conclusions: Clinical phenotypes of pediatric pulmonary hypertension are heterogeneous and overlapping, with clinical phenotypes that evolve throughout childhood. Despite widespread use of pulmonary arterial hypertension therapy, the prognosis remains poor.