Pulsed Doppler flow characteristics of ductus arteriosus in infants with associated congenital anomalies of the heart or great arteries.

Pulsed Doppler echocardiography (PDE) from the suprasternal approach was used to assess flow characteristics of ductus arteriosus (DA) in 145 infants (aged 1 day to 6 months) with major congenital heart disease. Direct ductal Doppler interrogation was possible in 138 patients and serial studies before and after medical treatment were performed in 28 infants. According to pulmonary artery pressure and associated heart lesions, 3 ductal shunting patterns were identified. An isolated left-to-right shunt, observed in isolated DA or in right ventricular outflow tract obstruction, was characterized by a continuous flow with a peak velocity in late systole. An isolated right-to-left shunt, observed in persistent fetal circulation and aortic arch abnormalities, was characterized by a continuous flow with a peak velocity in early systole. In patients with a bidirectional ductal shunt, the right-to-left shunt always occurred in systole and the left-to-right shunt began in late systole and extended into diastole. A systolic right-to-left shunt always corresponded to the presence of significant pulmonary hypertension. Ductal flow changes could be documented after prostaglandin E1 therapy in patients with ductus-dependent heart disease or after tolazoline therapy in patients with persistent fetal circulation. Thus, PDE with direct ductal Doppler interrogation is an important complement to the echocardiographic evaluation of DA. It is a safe noninvasive approach to ductal shunt and permits convenient evaluation of the effects of drugs on pulmonary artery resistance (tolazoline) and ductal patency (prostaglandin E1).