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

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-effect and HSROC model meta-analyses were used to analyse the data. RESULTS: -794 articles were identified and 12 (922 fetuses at risk for CoA) 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 compared to those without CoA (p=0.01). Mean Aortic valve diameter z-score was lower in fetuses with CoA compared to normal fetuses (p= <0.001), but the ascending aorta diameter, expressed as z-score or mm, 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 three-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 compared to controls, while aortic isthmus/arterial duct diameter ratio was lower in fetuses with CoA compared to those without CoA (p<0.001). The presence of coarctation shelf and aortic arch hypoplasia were more common in fetuses with CoA compared to controls (OR: 26.0, 95% CI 4.42-153, p<0.001 and OR: 38.2, 95% CI 3.01-486, p=0.005), while 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. Multi-parametric 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 in order to develop objective models for risk assessment in these fetuses.