Ductus arteriosus-dependent pulmonary circulation secondary to cardiac malformations in fetal life.

The objective of this study was to describe the characteristic prenatal findings of a ductus arteriosus-dependent pulmonary circulation secondary to cardiac malformations. B-mode, color and pulsed wave Doppler echocardiography were performed in seven fetuses with severe pulmonary stenosis or atresia. All findings were confirmed postnatally by echocardiography and cardiac catheterization or autopsy. Severe fetal pulmonary stenosis or atresia was characterized by decreased pulmonary valve diameters, frequently with reduced pulmonary artery diameters, increased flow velocities or absent flow across the stenotic pulmonary valve, increased ascending aorta diameters, slightly increased aortic velocities and normal umbilical and middle cerebral artery Doppler wave forms. In all cases, prenatal assessment of neonatal ductus dependence was possible by demonstrating reverse flow across the fetal ductus with peak systolic velocities ranging from 0.9-2.0 m/s and absent diastolic flow. Ductal diameters were slightly decreased, ranging from 2-4 mm. Prenatal detection of a ductus-dependent pulmonary circulation is a strong indication of the presence of severe pulmonary stenosis or atresia. Its diagnosis allows avoidance of maternal administration of drugs with constrictive effects upon the ductus, interdisciplinary planning of perinatal management, early postnatal confirmation of the diagnosis, and early postnatal intervention, in particular administration of prostaglandins to prevent life-threatening ductal closure.