Fetal aortic arch and its branches anomalies: prenatal ultrasound, vascular cast and gene detection

Objective To explore the application values of prenatal ultrasound, vascular cast in the diagnosis of fetal aortic arch and its branches anomalies and to analyze the genetic characteristics by gene detection. Methods Twenty-two cases of the vascular cast specimens of the fetal aortic arch and its branches anomalies were analyzed and studied by comparing with their prenatal ultrasonography. Then the characteristics of each type of fetal aortic arch and its branches anomalies, the missed diagnosis and misdiagnosis were summarized and the results of their gene detection were also analyzed. Results The 22 cases of fetal aortic arch and its branches anomalies were as follows: 2 cases of double aortic arch showed the ascending aorta was divided into two branches after converging as the descending aorta. Three cases were left aortic arch with aberrant right subclavian artery. Twelve cases were right aortic arch: 8 cases were right aortic arch with mirror-image branching, 3 cases were right aortic arch with aberrant left subclavian artery, 1 case was right aortic arch with isolated left subclavian artery. Of the 8 right aortic arch with mirror-image branching, 3 cases of left arterial duct showed the vertical walking between the fusion site of the left innominate artery and the pulmonary artery. Right aortic arch with aberrant left subclavian artery with arterial duct showed U shaped vascular ring. Five cases were other types, including 2 cases of the coarctation of aortic arch, 1 case of interrupted aortic arch, 1 case of pulmonary artery sling, and 1 case of abnormal origin of right pulmonary artery. The ultrasonic missed diagnosis were the 6 deformities: 3 cases of arterial duct and 3 cases of aberrant subclavian artery. The ultrasonic misdiagnosis were the 5 deformities: 2 cases of arterial duct location, 1 case of aberrant subclavian artery, 1 case of isolated left subclavian artery, and 1 case of the coarctation of aortic arch. Genetic test results: In the 18 cases of the genetic detection, 2 cases were positive, 1 case was 22q11.2 microdeletion syndrome and 1 case was carrying KMT2D gene variant. Conclusions There are various kinds of fetal aortic arch and its branches anomalies, which are often associated with intracardiac malformations and venous branches variation. And prenatal ultrasound is of great value in diagnosing them.Vascular cast can visually display their characteristic changes, which is helpful to improve the differential diagnosis of the different aortic arch and its branches anomalies. The detailed genetic detection can improve the further understanding of its etiology. Key words: Ultrasonography, prenatal; Fetus; Aortic arch anomalies; Vascular cast; Gene detection