Risk Factors for Coarctation of the Aorta on Prenatal Ultrasound: A Systematic Review and Meta-Analysis

Background: Prenatal diagnosis of coarctation of the aorta (CoA) is still challenging and affected by high rates of false-positive diagnoses. The aim of this study was to ascertain the strength of association and to quantify the diagnostic accuracy of different ultrasound signs in predicting CoA prenatally.

Methods: Medline, Embase, CINAHL, and Cochrane databases were searched. Random-effects and hierarchical summary receiver operating characteristic model meta-analyses were used to analyze the data.

Results: Seven hundred ninety-four articles were identified, and 12 (922 fetuses at risk for CoA) articles were included. Mean mitral valve diameter z score was lower (P<0.001) and the mean tricuspid valve diameter z score was higher in fetuses with CoA than in those without CoA (P=0.01). Mean aortic valve diameter z score was lower in fetuses with CoA than in healthy fetuses (P≤0.001), but the ascending aorta diameter, expressed as z score or millimeters, was similar between groups (P=0.07 and 0.47, respectively). Mean aortic isthmus diameter z scores measured either in sagittal (P=0.02) or in 3-vessel trachea view (P<0.001) were lower in fetuses with CoA. Conversely, the mean pulmonary artery diameter z score, the right/left ventricular and pulmonary artery/ascending aorta diameter ratios were higher (P<0.001, P=0.02, and P=0.02, respectively) in fetuses with CoA in comparison with controls, although aortic isthmus/arterial duct diameter ratio was lower in fetuses with CoA than in those without CoA (P<0.001). The presence of coarctation shelf and aortic arch hypoplasia were more common in fetuses with CoA than in controls (odds ratio, 26.0; 95% confidence interval, 4.42-153; P<0.001 and odds ratio, 38.2; 95% confidence interval, 3.01-486; P=0.005), whereas persistent left superior vena cava (P=0.85), ventricular septal defect (P=0.12), and bicuspid aortic valve (P=0.14) did not carry an increased risk for this anomaly. Multiparametric diagnostic models integrating different ultrasound signs for the detection of CoA were associated with an increased detection rate.

Conclusions: The detection rate of CoA may improve when a multiple-criteria prediction model is adopted. Further large multicenter studies sharing the same imaging protocols are needed to develop objective models for risk assessment in these fetuses.