General Consideration
PDA is the persistence of the normal fetal vessel joining the pulmonary artery to the aorta. It closes spontaneously in normal term infants at 3-5 day of age. PDA accounts for 10% of all congenital heart disease. The incidence of PDA is preterm infants born at altitudes over 10,000 ft. It is twice as common in females as in males. The frequency of PDA in preterm infants weighing less than 1500g ranges from 20-60%. The defect may occur as an isolated abnormality or with associated lesions, commonly coarctation of the aorta and VSD. It is critical to recognize patients with a PDA, but without readily apparent findings of other associated lesions who are being kept alive by the paten ductus (eg, a patient with PDA and unsuspected pulmonary atresia)