Is retrograde blood flow of aortic isthmus useful for the prenatal screening of coarctation of the aorta by fetal color Doppler echocardiography? A preliminary study

Purpose To validate the relationship between retrograde blood flow in the aortic isthmus (AoI-R) by color Doppler in fetal echocardiography and postnatal coarctation of the aorta (CoA) diagnosed as isthmus narrowing. Methods This was a retrospective study of 22 cases of prenatally suspected simple CoA or CoA with small ventricular septum defect based on fetal echocardiography performed by pediatric cardiologists in our hospital. Gestational age at the first detection of AoI-R and the optimal cut-off value for the prediction of postnatal CoA were mainly evaluated according to the postnatal diagnosis of CoA. Results All 22 cases had AoI-R prenatally, and nine of them (40.9%) had isthmus narrowing and were diagnosed as having CoA immediately after birth. The gestational age at the first detection of AoI-R was significantly lower in cases with postnatal CoA than in those without (average 34.4 weeks; P = 0.034). The cut-off value for the prediction of postnatal CoA was 35.5 weeks of gestation, with a sensitivity and specificity of 77.8 and 69.2%, respectively. Conclusion AoI-R determined by color Doppler echocardiography can become a useful tool in the screening of fetal CoA, especially at