Pulmonary hypertension in children: a historical overview.

Pulmonary arterial hypertension in children contributes significantly to morbidity and mortality in diverse pediatric cardiac, lung, hematologic, and other diseases. Pulmonary arterial hypertension is generally a disease of small pulmonary arteries characterized by vascular narrowing due to high-tone and abnormal vasoreactivity, structural remodeling of the vessel wall, intraluminal obstruction, and decreased vascular growth and surface area. Without therapy, high pulmonary vascular resistance contributes to progressive right ventricular failure, low cardiac output, and death. Advances in basic pulmonary vascular biology over the last few decades have led directly to several novel therapies, which have significantly expanded therapeutic choices and have led to improved survival and quality of life of many children with pulmonary arterial hypertension. Despite these improvements, long-term outcomes in many settings remain guarded and substantial challenges persist, especially with regard to understanding mechanisms and approach to structural remodeling of severe pulmonary arterial hypertension.