A 26-year-old pregnant woman (gravida 1, para 0) was referred to our institution for management of suspected fetal CHAOS after a routine detailed obstetric sonogram at 22 weeks' gestation showed fetal ascites and enlarged echogenic lungs (Fig. 1A
). The four-vessel view of the heart was normal. A repeat sonogram at 24 weeks' gestation confirmed the findings of pulmonary enlargement with fetal hydrops and ascites, but dilated airways were not seen and the central airway was considered normal.
In view of these atypical features, MRI was performed at 24 weeks' gestation, confirming the presence of ascites and pulmonary overexpansion. In addition, MRI showed mildly dilated intrapulmonary airways with apparent narrowing of the central airway between the thoracic inlet and the carina (Figs. 1B
). The central airway appeared otherwise patent without intrinsic occlusion (Fig. 1D
). The possibility of extrinsic vascular compression was raised and was subsequently confirmed on fetal echocardiography, which showed a double aortic arch with a dominant right arch, a smaller left arch, and left ductal arch forming a ring surrounding the trachea (Figs. 1E
). On pulsed Doppler interrogation, left and right ventricular inflow patterns and flow patterns in the inferior vena cava (no increase in a
reversal), ductus venosus (no a
wave reversal), and umbilical vein (no pulsations) appeared normal. The diagnosis was further confirmed by the presence of mirror image bifurcated brachiocephalic arteries in the same plane, cephalad to the aortic arch (Fig. 1G
A female infant was delivered vaginally at 30 weeks' gestation after spontaneous preterm labor. The infant required immediate intubation for respiratory insufficiency. Extubation was not possible until the nondominant arch was surgically divided at 6 weeks of age. Subsequent postoperative recovery was uneventful.