Sagittal aortic-arch assessment for prenatal diagnosis of coarctation of the aorta: comparative evaluation of 10 published methods and a new predictive model.

Abstract

To externally validate the diagnostic performance of 10 previously published fetal echocardiographic sagittal aortic-arch parameters and to develop an optimal predictive model based on these parameters for the prenatal identification of neonatal coarctation of the aorta (CoA). This was a retrospective, multicenter diagnostic cohort study, including pregnancies with suspected fetal CoA and postnatal diagnostic confirmation. Sagittal aortic-arch videoclips obtained from patients at two tertiary referral centers in Thailand between January 2014 and January 2025 were reviewed offline by a single investigator blinded to the final diagnosis to assess 10 predefined echocardiographic parameters of the aortic arch, including vascular diameters, interarterial distances, vessel angles and the presence of a shelf sign. The discriminatory performance of the 10 published predictors for neonatal CoA was evaluated using univariate binary logistic regression and receiver-operating-characteristics (ROC)-curve analysis. A final predictive model was developed by entering the 10 sagittal aortic-arch parameters into a multivariable logistic regression model and applying backward elimination to derive the model with the fewest parameters without compromising discriminatory performance. Of the 154 fetuses included in the study, 82 (53.2%) were subsequently diagnosed with neonatal CoA. Fetuses subsequently diagnosed with neonatal CoA had a significantly longer left common carotid artery-left subclavian artery (LCCA-LSCA) distance (median, 3.12 mm vs 2.14 mm; P = 0.001) and a higher prevalence of the shelf sign (74.4% vs 50.0%; P = 0.002). Among individual parameters, the carotid-subclavian artery index showed the highest diagnostic accuracy for predicting neonatal CoA (area under the ROC curve (AUC), 0.684 (95% CI, 0.600-0.767)). The final multivariable model, incorporating LCCA-LSCA distance, LSCA diameter, descending aortic diameter and the presence of the shelf sign, demonstrated moderate performance (AUC, 0.749 (95% CI, 0.672-0.826)). At a predicted probability cut-off of 0.45, the sensitivity and specificity of the combined model for the prenatal identification of neonatal CoA were 84.1% (95% CI, 74.4-91.3%) and 54.2% (95% CI, 42.0-66.0%), respectively. In fetuses with suspected CoA, a multiparametric predictive model based on sagittal aortic-arch assessment improves prenatal diagnosis compared with previously published methods. A longer LCCA-LSCA distance, the presence of the shelf sign and an increased LSCA diameter are useful for distinguishing true-positive cases of CoA during fetal echocardiography. © 2026 International Society of Ultrasound in Obstetrics and Gynecology.