Registries for paediatric pulmonary hypertension.

Pulmonary arterial hypertension (PAH) is a progressive, angio-obliterative disease leading to increased pulmonary vascular resistance, right heart failure, and death in ,25–60% of PAH patients 5 years after diagnosis [1–3]. The estimated prevalence of PAH is 15–50 cases per million adults [4–6] and 2–16 cases per million children [7–9]. In certain at-risk groups, however, the occurrence of PAH is substantially higher. For example, the prevalence is 0.5% in HIV-infected patients [10] and 4–6% in schistosomiasis [11]. These diseases are far more common in developing countries with limited health care and, thus, the real burden of PAH worldwide is probably underestimated.