Accuracy of Fetal Echocardiography in the Differential Diagnosis between Truncus Arteriosus and Pulmonary Atresia with Ventricular Septal Defect

OBJECTIVES: To report on the accuracy of fetal echocardiography in the distinction between truncus arteriosus communis (CAT) and pulmonary atresia with ventricular septal defect (PA-VSD) and to describe the association with extracardiac and chromosomal anomalies.

METHODS: This was a retrospective study on 31 fetuses with a single arterial trunk overriding a VSD with a nonidentifiable right ventricle outflow tract with anterograde flow. Data on the type of cardiac defect, gestational age, characteristics of the arterial trunk valve, presence of additional vascular, chromosomal and extracardiac abnormalities and postnatal outcome were obtained. Misdiagnosed cases were reevaluated by four-dimensional spatiotemporal image correlation (4D-STIC) echocardiography.

RESULTS: The overall diagnostic accuracy was 81% and increased to 93.5% with 4D-STIC. Chromosomal and extracardiac anomalies were detected in 40 and 27%, respectively. In the PA-VSD group, patent ductus arteriosus and major aortopulmonary collateral arteries (MAPCAs) were present in 70 and 50% of the cases, respectively, coexisting in 1 of 5 cases. MAPCAs were significantly associated with a right aortic arch and with a 22q11 microdeletion in 50% of cases.

CONCLUSIONS: A prenatal distinction between CAT and PA-VSD can currently be achieved in most cases. MAPCAs should be actively searched for when PA-VSD is suspected, as they are associated with a higher risk of 22q11 microdeletion and potentially complicate postnatal treatment.