pediatrics
Patent Ductus Arteriosus (PDA)
Pathophysiology of PDA
The ductus arteriosus is a normal connection between the pulmonary artery and aorta; it is necessary for proper fetal circulation. At birth, the rise in PaO2 and decline in prostaglandin concentration cause closure of the ductus arteriosus, typically beginning within the first 10 to 15 hours of life. If this normal process does not occur, the ductus arteriosus will remain patent (see figure). Pulmonary blood flow, LA and LV volumes, and ascending AO volume are increased. AO=aorta; LA=left atrium; LV=left ventricle; PA=pulmonary artery. Physiologic consequences depend on ductal size. A small ductus rarely causes symptoms. A large ductus causes a large Left-to-right shunts . If uncorrected, over time, a large shunt results in left heart enlargement, pulmonary artery hypertension, and elevated pulmonary vascular resistance, ultimately leading to 