Fetal Right Aortic Arch: A Quantitative Method of Outcome Prediction.

OBJECTIVE: To investigate right aortic arches (RAA) quantitatively and risk-stratify fetuses with RAA prenatally.

METHOD: A total of 143 singleton fetuses were enrolled. Four measurements were studied, including the angle and distance between the aortic arch (AO) and ductal arch (DA), the diameters of the AO and DA, and the distance growth rate (DGR).

RESULT: A significant increase in mean distance was observed in the study group (4.89 ± 1.07 mm) compared to the control group (1.62 ± 0.33 mm, p<.01). The distance increased from the second (1.52 ± 0.35 mm, p<.01, 4.06 ± 0.78 mm, p<.01) to third trimester (1.71 ± 0.29 mm, p<.01, 5.13 ± 1.10 mm, p<.01) in the normal and study groups. Fetuses with abnormalities in addition to RAAs had significantly lower growth rates (12.4 ± 5.2%) than those with an isolated RAA (33.7 ± 12.0%).

CONCLUSION: Parameters, especially DGR, may be clinically significant. DGR may be restricted when an RAA exists with other malformations. Decreasing DGR in fetuses with RAAs suggests the presence of other malformations.