• The ductus arteriosus allows blood to flow from the pulmonary artery to the aorta during fetal life.
• Failure of the normal closure of this vessel results in a PDA .
• With a falling pulmonary vascular resistance after birth, left-to-right shunting of blood and increased pulmonary blood flow occur.
• Excluding premature infants, PDAs = 5%-10% of congenital heart disease.