Combined fetal echocardiographic views improved prenatal differential diagnosis between right aortic arch and double aortic arch: a multicenter research.

Purpose: Congenital right aortic arch (RAA) and double aortic arch (DAA) were difficult to be diagnosed by traditional fetal echography. However, these two diseases have distinct clinical therapies and long-term outcomes which makes the differential diagnosis of great importance. While fetal screening by traditional fetal echography provides limited information about the branches of the aortic arch. This study aimed to discover and evaluate a novel combination of different echocardiography views in the diagnosis and differentiation of RAA and DAA.

Methods: From January 2014 to December 2022, a total of 414,686 pregnant women underwent routine ultrasound examinations of the fetus during the second trimester. The scan of the fetal heart included a fetal four-chamber view, The left ventricular outflow tract (LVOT) view, a right ventricular outflow tract (RVOT) view, a three-vessel (3 V) view, and three vessels and trachea (3VT) view. Then the cases diagnosed as RAA or DAA by initial ultrasound screening from two hospitals were divided into the RAA group and the DAA group. Then enter the prenatal diagnosis consultation. All the pregnant women were offered invasive prenatal diagnosis. Genetic tests were fully discussed and decided after genetic counseling. Further ultrasound examination by two more experienced sonographers, in addition to the fetal echocardiogram views, includes further multi-angle scanning of the aortic arch branches with color Doppler flow imaging (CDFI) or high definition flow imaging (HDFI) for further diagnosis, and the reasons for misdiagnosis were analyzed and summarized.

Results: A total of 332 cases were diagnosed with RAA or DAA by initial ultrasound, including RAA group 244 cases and DAA group 88 cases. In the RAA group, the mirror RAA (MRAA) could not be completely diagnosed by 3VT view alone in traditional echocardiography, with accuracy and sensitivity of 88.9% and 72.6%, respectively. In the DAA group, 36 cases were misdiagnosed only by 3VT view alone in traditional echocardiography, with the accuracy and specificity of 88.9% and 86.8%, respectively. However, the accuracy for MRAA or DAA could reach 100% when combined with 3VT and multi-angle scanning of the aortic arch branches. The abnormal detection rate of genetic tests was 10.5% (20/190), excluding the cases who refused the invasive prenatal diagnosis.

Conclusion: Combining 3VT and multi-angle scanning of the aortic arch branches With CDFI or HDFI could effectively distinguish RAA variants from DAA. The invasive prenatal diagnosis should be recommended for patients with RAA or DAA, and the accurate prenatal diagnosis was highly valuable in providing appropriate perinatal counseling and prognostic evaluation.