This procedure entails the placement of an extracardiac valved or valveless conduit and closure of the ventricular septal defect. Most patients, however, require replacement of the conduit, either because they outgrow the conduit or as a result of conduit stenosis. The use of adult size allografts may decrease the need for reoperation 17,20 . When prenatal diagnosis of truncus arteriosus is made before viability, termination of pregnancy can be offered. A meticulous search for associated anomalies should be performed.
Chromosomal analysis is advised, especially in the presence of associated anomalies.
Serial ultrasonic evaluation is recommended to follow fetal growth, amniotic fluid volume, and to detect signs of fetal hydrops. Truncal valve competence can be assessed with pulsed Doppler or with color flow imaging. If incompetence of the truncal valve is detected, the fetus may be at increased risk of developing hydrops. If there are no other complicating factors, standard obstetrical management for labor and delivery is recommended. However, it is essential for delivery to occur in a tertiary care center where a pediatric cardiologist is available to assist in the neonatal management of these patients.