P04.12: A rare variant of the fetal transposition of the great arteries: diagnostic difficulties

Abstract

To present a case of fetal transposition of the great arteries with the rare variant of the aorta in posterior position because we believe it is more difficult to diagnose. Furthermore, this variant is not usually described in articles or books concerning the transposition of the great arteries. We saw the patient for the first time in the 23rd week of pregnancy. The fetal exploration was normal, except for the cardiac examination in which we only detected two vessels in the three-vessel view. One of the vessels was the superior vena cava and the other was an artery. With these findings we considered the diagnosis of truncus arteriosus, but after viewing many sections, we detected the outflow of the aorta in a very deviated and posterior position. This was the reason why we could not detect the three vascular structures in the three-vessel view. When looking for the appearance of outflow tracts, we saw that the pulmonary vessels arise from the left ventricle and the aorta from the right ventricle. This was the clue to making the diagnosis of transposition of the great arteries with posterior position of the aorta. In this case of transposition of the arteries with abnormal position of the aorta the correct diagnosis of the cardiac malformation may be difficult.