Pediatric pulmonary hypertension in the Netherlands: epidemiology and characterization during the period 1991 to 2005.

Background: Incidence and prevalence rates for pediatric pulmonary hypertension (PH) and pulmonary arterial hypertension (PAH) are unknown. This study describes the nationwide epidemiological features of pediatric PH in the Netherlands during a 15-year period and the clinical course of pediatric PAH.
Methods and Results: Two registries were used to retrospectively identify children (0-17 years) with PH. Overall, 3263 pediatric patients were identified with PH due to left heart disease (n=160; 5%), lung disease/hypoxemia (n=253; 8%), thromboembolic disease (n=5; <1%), and transient (n=2691; 82%) and progressive (n=154; 5%) PAH. Transient PAH included persistent PH of the newborn and children with congenital heart defects (CHD) and systemic-to-pulmonary shunt, in whom PAH resolved after successful shunt correction. Progressive PAH mainly included idiopathic PAH (n=36; iPAH) and PAH associated with CHD (n=111; PAH-CHD). Pulmonary arterial hypertension associated with CHD represented highly heterogeneous subgroups. Syndromes were frequently present, especially in progressive PAH (n=60; 39%). Survival for PAH-CHD varied depending on the subgroups, some showing better and others showing worse survival than for iPAH. Survival of children with Eisenmenger syndrome appeared worse than reported in adults. For iPAH and PAH-CHD, annual incidence and point prevalence averaged, respectively, 0.7 and 4.4 (iPAH) and 2.2 and 15.6 (PAH-CHD) cases per million children. Compared to studies in adults, iPAH occurred less whereas PAH-CHD occurred more frequently.
Conclusions: Pediatric PH is characterized by various age-specific diagnoses, the majority of which comprise transient forms of PAH. Incidence of pediatric iPAH is lower whereas incidence of pediatric PAH-CHD is higher than reported in adults. Pediatric PAH-CHD represents a heterogeneous group with highly variable clinical courses.