The role of the three vessels and trachea view (3VT) in the diagnosis of congenital heart defects.

OBJECTIVE To analyse the anomalies seen at the three vessels and trachea (3VT) view in fetuses with antenatally diagnosed congenital heart disease (CHD), specifically in defects involving the upper mediastinum, including the outflow tracts and/or arteries. METHODS Seventy-four consecutive fetuses of singleton pregnancies with antenatally diagnosed structural heart defects were initially included in the study. We selected those in which there was an anomaly seen on the 3VT view and classified them into groups: abnormalities detected on the upper mediastinum (abnormal vessel size, alignment, arrangement and number), abnormal location of the transverse aortic arch in relation to the trachea, and abnormal functional behavior of the arterial vessels (reversed flow and turbulent flow) detected using color Doppler. The abnormalities detected were confirmed postnatally by a pediatric cardiologist, echocardiography and/or autopsy. RESULTS Thirty-four of the 74 fetuses showed an abnormal 3VT view that could be classified into one of the groups. We classified the lesions according to the most evident abnormal finding during the examination. Gestational age ranged from 17 to 39 (mean, 30) weeks. Abnormal vessel size was found in 20 of the 74 fetuses, abnormal vessel alignment was found in two fetuses, and abnormal vessel arrangement in three fetuses. Two vessels instead of three were found in five fetuses and four vessels were found in two fetuses. Abnormal visualization of the trachea, between the pulmonary artery and the transverse arch, occurred in one fetus with isolated right aortic arch. We found reversed flow in the transverse aortic arch in three fetuses with aortic atresia and in two fetuses with severe coarctation of the aorta. Reversed flow in the pulmonary trunk was seen in a fetus with pulmonary atresia and double outlet right ventricle. Turbulent flow was found in two fetuses with outflow tract stenosis. CONCLUSION Our study, descriptive in nature, demonstrates that the 3VT view is a reliable method with which to determine abnormalities in the upper mediastinum. It proved to be efficient in identifying an important group of critical heart defects involving the outflow tracts and the aortic arch. It also provided important clues to the diagnosis of minor anomalies considered as markers of other CHD. We believe that use of the 3VT view should become routine in screening for CHD.