Echocardiographic findings for improved prenatal diagnosis of aortic coarctation with ventricular septal defect.

Accurate prenatal diagnosis of coarctation of the aorta (CoA) associated with ventricular septal defect (VSD) remains challenging. The objective of the study was to identify which Doppler and/or two-dimensional sonographic findings are most useful for predicting fetal CoA/VSD. A retrospective cohort study identified 35 fetuses with suspected CoA/VSD. Prenatal imaging characteristics included the right ventricular/left ventricular, pulmonary artery (PA)/aorta ratio, aortic isthmus (AOI) Z score, diastolic velocity-time integral (VTID), and systolic velocity-time integral (VTIS) at the AOI. The area under the receiver operating characteristic curve (AUC), integrated discrimination improvement (IDI), and net reclassification improvement (NRI) were calculated. Significant differences in the PA/AO, VTID, VTID/VTIS, VTID/VTIS, VTID/(VTID + VTIS), and AOI Z score between the true CoA group and false positives were found. When associated with VSD, the VTID/VTIS and VTID/(VTID + VTIS) had the highest AUC (0.97, 95% confidence interval: 0.84-1.00), with 88.46% sensitivity and 100.00% specificity for predicting the true CoA. The AOI Z score had the highest sensitivity (92.31%). Adding the VTID/VTIS to the AOI Z score significantly improved the performance (IDI, 50%; NRI, 82%; P < 0.05), with an improvement in specificity (77.78% vs. 55.56%; non-Event P = 0.008) without sacrificing sensitivity (96.15% vs. 92.31%; Event P = 0.564). In fetuses with suspected CoA associated with VSD, the quantitative spectral Doppler metric aided accurate detection of the fetal CoA, with reduced false positives. The conventional AOI Z score plus spectral Doppler metric may improve the overall diagnostic accuracy of CoA/VSD.