Abstract
Childrens with Down syndrome (DS) has a greater risk of pulmonary arterial hypertension (PAH) than the general pediatric patients. The reasons of PAH are mainly due to probably genetic backgrounds, specific structure of pulmonary vascular wall, certain types of congenital heart diseases, and partly due to pulmonary hypoplasia, upper and lower airway obstructive diseases, chronic infection, and neuro-muscular underdevelopment. Exposure to increased left to right shunt results in increased sheer stress on pulmonary endothelial cells and may induce endothelial dysfunction followed by irreversible pulmonary arterial remodeling.
The pathological changes are characterized by endothelial cell proliferation and thickening of pulmonary arterial vessel wall due to mechanical responses to thinner medial smooth muscle cell (SMC) layer and pulmonary hypoplasia (under development of alveoli). DS patients has decreased production of prostacycline and Nitrate, but elevated endothelin-1 and thromboxane. Perioperative periods, DS may develop post ICR PAH crisis, poorer response to nitric oxide (NO) inhalation, and prolonged PAH status.
For better management of DS patients, it is crucial to evaluate systemic complications with pediatric cardiologists, pulmonologists, neurologists, and adult cardiologists. At the cardiac catheterization, pulmonary arterial resistance is a kee-data for assessing the severity of PAH, and response to vasodilating agents for preventing postoperative PAH crisis, and for indication of intracardiac repair.
The advanced therapy with recently developed pulmonary vasodilating agents seems to be effective for DS patients. Operative risk is not so high even in DS patients except patients with severe AVSD compared to non-DS patients. Optimal timing and modalities for evaluation are essential.
