We used pulsed Doppler ultrasound to determine the flow dynamics of the aorta and patent ductus arteriosus (PDA) in 21 infants (ages 1 to 16 days) with PDA and aortic atresia (n = 15) or aortic stenosis (n = 6). The flow within the PDA was recorded in 19, and was right-to-left during systole in all. There was a diastolic left-to-right PDA shunt in 11 patients with aortic atresia and in three with aortic stenosis, and the shunt was associated with large (3 to 11 mm in diameter) interatrial communications. In two patients with aortic atresia and three with aortic stenosis, however, the diastolic PDA shunt was from right to left, and the interatrial communications were small (0 to 2 mm in diameter). The right-to-left diastolic PDA shunting may be best explained by the relative pulmonary (high with left-sided inflow obstruction and a small interatrial communication) and systemic resistances. All patients with aortic atresia and three with aortic stenosis had retrograde systolic flow in the transverse aortic a...
Read full abstract