The Diastolic and Systolic Velocity-Time Integral Ratio of the Aortic Isthmus Is a Sensitive Indicator of Aortic Coarctation in Fetuses

•Prenatal diagnosis of CoA is challenging with 2D measurement. •Spectral Doppler technology is associated with an increased detection rate of fetal CoA. •Combined 2D measurement and Doppler evaluation can improve diagnostic accuracy of CoA. Background Prenatal diagnosis of coarctation of the aorta (CoA) is challenging and is affected by high false-positive and false-negative rates. The aim of this study was to identify sonographic criteria to improve the identification of fetal CoA. Methods A retrospective review was conducted of subjects with prenatal suspicion for CoA who also had postnatal follow-up. Sixty-nine fetuses were identified with possible CoA, and 47 normal fetuses were selected as control subjects. Retrospective measurements of right ventricular/left ventricular ratio, pulmonary artery/aorta ratio, aortic isthmus (AOI) Z score, diastolic velocity-time integral (VTID), and systolic velocity-time integral (VTIS) at the AOI were recorded. Receiver operating characteristic curve analysis identified the parameter most predictive of postnatal CoA. Results When comparing subjects with (n = 31) and without (n = 38) CoA, significant differences were detected for the AOI Z score, VTID, VTID/VTIS ratio, and VTID/(VTID + VTIS) ratio (P < .001). The areas under the receiver operating characteristic curve were 0.92, 0.92, 0.78, 0.74, 0.71, and 0.68 for the VTID/VTIS ratio, VTID/(VTID + VTIS) ratio, VTID, AOI Z score (sagittal view), AOI Z score (three-vessel tracheal view), and pulmonary artery/aorta ratio, respectively. There was a 25% (95% CI, 14%–35%) improvement in the area under the curve after adding the VTID/VTIS ratio to the basic model (AOI Z score [sagittal view]), and this ratio (after transformation) showed significantly better discrimination and reclassification ability for determining CoA. The pulmonary artery/aorta ratio, VTID, VTID/VTIS ratio, and VTID/(VTID + VTIS) ratio were stable throughout the normal fetal developmental period in this study. Conclusions In cases with suspected prenatal diagnosis of CoA, evaluation of spectral Doppler measurements, such as the VTID/VTIS ratio, may enhance the accuracy of diagnosis with fetal echocardiography. Prenatal diagnosis of coarctation of the aorta (CoA) is challenging and is affected by high false-positive and false-negative rates. The aim of this study was to identify sonographic criteria to improve the identification of fetal CoA. A retrospective review was conducted of subjects with prenatal suspicion for CoA who also had postnatal follow-up. Sixty-nine fetuses were identified with possible CoA, and 47 normal fetuses were selected as control subjects. Retrospective measurements of right ventricular/left ventricular ratio, pulmonary artery/aorta ratio, aortic isthmus (AOI) Z score, diastolic velocity-time integral (VTID), and systolic velocity-time integral (VTIS) at the AOI were recorded. Receiver operating characteristic curve analysis identified the parameter most predictive of postnatal CoA. When comparing subjects with (n = 31) and without (n = 38) CoA, significant differences were detected for the AOI Z score, VTID, VTID/VTIS ratio, and VTID/(VTID + VTIS) ratio (P < .001). The areas under the receiver operating characteristic curve were 0.92, 0.92, 0.78, 0.74, 0.71, and 0.68 for the VTID/VTIS ratio, VTID/(VTID + VTIS) ratio, VTID, AOI Z score (sagittal view), AOI Z score (three-vessel tracheal view), and pulmonary artery/aorta ratio, respectively. There was a 25% (95% CI, 14%–35%) improvement in the area under the curve after adding the VTID/VTIS ratio to the basic model (AOI Z score [sagittal view]), and this ratio (after transformation) showed significantly better discrimination and reclassification ability for determining CoA. The pulmonary artery/aorta ratio, VTID, VTID/VTIS ratio, and VTID/(VTID + VTIS) ratio were stable throughout the normal fetal developmental period in this study. In cases with suspected prenatal diagnosis of CoA, evaluation of spectral Doppler measurements, such as the VTID/VTIS ratio, may enhance the accuracy of diagnosis with fetal echocardiography.