Background: Coarctation of the aorta is one of the most common congenital heart malformations, accounting for approximately 7% of all live births with congenital heart disease. It is crucial to make a definitive prenatal diagnosis as it can inform clinical treatment decisions.

Objective: The diagnostic criteria for coarctation of the aorta are still controversial, and there is currently no risk nomogram available to assess the probability of coarctation of the aorta using routine ultrasound parameters. We explored the prenatal diagnostic efficacy of ultrasound parameters and established a nomogram for coarctation of the aorta.

Methods: A total of 101 fetuses with suspected coarctation of the aorta diagnosed by prenatal ultrasound from July 2015 to June 2023 were collected retrospectively. The patients were divided into two groups according to the diagnostic

Results: a normal group (n=42; gestational weeks, 28.5±6.0) and a coarctation of the aorta group (n=59; gestational weeks, 26.7±5.1). Univariate and multivariate logistic regression analyses were used to identify echocardiographic predictors of coarctation of the aorta. Moreover, the patients were divided into a training set and a validation set in a ratio of 8:2, and a nomogram for the prenatal diagnosis of coarctation of the aorta was established using R. Results: (1) Aortic isthmus, aortic isthmus z-score, ascending aorta, ascending aorta z-score, pulmonary artery, pulmonary artery z-score, pulmonary artery/ascending aorta ratio, persistent left superior vena cava, and aortic arch dysplasia were the predictive markers of coarctation of the aorta in the univariate logistic regression analysis (P<0.05). (2) Aortic isthmus z-score, ascending aorta z-score, pulmonary artery/ascending aorta ratio, persistent left superior vena cava, and aortic arch dysplasia were identified as the final predictors after multivariate logistic regression analysis (P<0.05). (3) The combined model, which included aortic isthmus z-score, ascending aorta z-score, pulmonary artery/ascending aorta ratio, persistent left superior vena cava, and aortic arch dysplasia, demonstrated a larger area under the receiver operating characteristic curve (AUC) (AUC=0.96, sensitivity=93.22%, specificity=88.10%) than aortic isthmus z-score alone (AUC=0.77, sensitivity=77.97%, specificity=71.43%), ascending aorta z-score alone (AUC=0.78, sensitivity=54.24%, specificity=90.48%), pulmonary artery/ascending aorta ratio alone (AUC=0.68, sensitivity=72.88%, specificity=54.76%), aortic arch dysplasia alone (AUC=0.70, sensitivity=66.10%, specificity=73.81%), and persistent left superior vena cava alone (AUC=0.72, sensitivity=79.66%, specificity=64.29%). The nomogram, which was constructed with these parameters, also exhibited excellent calibration curves and a good decision curve analysis curve.

Conclusions: The nomogram established by aortic isthmus z-score, ascending aorta z-score, pulmonary artery/ascending aorta ratio, persistent left superior vena cava, and aortic arch dysplasia demonstrated excellent efficacy in the prenatal diagnosis of coarctation of the aorta.