Idiopathic Pulmonary Arterial Hypertension in Children: A Review

Pediatric pulmonary hypertension (PH) is a heterogeneous disorder that leads to significant morbidity and mortality if left untreated. The Nice WHO classification from 2013 classifies PH into five groups: broadly, Group I pulmonary arterial hypertension (PAH), which includes idiopathic PAH, PAH associated with congenital heart disease and others; Group II comprises post-capillary PH (left heart disease), Group III comprises lung disease, Group IV thromboembolic disease and Group V miscellaneous causes of PH. The majority of pediatric PH comprise either Group I or Group III PH, but often children manifest features of several groups and are treated with targeted therapy. PAH in children requires a multifaceted approach. The pathogenesis is complex and it involves pulmonary vasoconstriction, endothelial dysfunction, inflammation and cell proliferation. Large multicenter and international registries have been formed with the aim of furthering understanding of this disease and developing appropriate therapeutic guidelines for managing pediatric PH. In this review, we describe the epidemiology, pathophysiology, clinical presentation, diagnosis and management of pediatric pulmonary hypertension.