Early Postnatal Echocardiography in Neonates with a Prenatal Suspicion of Coarctation of the Aorta.

Coarctation of the aorta (COA) is suspected prenatally when there is ventricular asymmetry, arterial disproportion, and hypoplasia of the aortic arch/isthmus. The presence of fetal shunts creates difficulty in prenatal confirmation of the diagnosis so serial echocardiography after birth is necessary to confirm or refute the diagnosis. The first neonatal echocardiogram in prenatally suspected cases of COA was assessed for prediction of neonatal COA repair (NCOAR). This included morphological assessment, measurement of the aortic arch and calculation of the distal arch index (DAI = distance between left common carotid and left subclavian artery/diameter of the distal arch). NCOAR was undertaken in 23/60 (38%) cases. Transverse arch, aortic isthmus z-score, and DAI had an area under the receiver operator curve of 0.88 (95% CI 0.77-0.98), 0.86 (95% CI 0.75-0.96), and 0.84 (95% CI 0.74-0.95), respectively for the prediction of NCOAR. Using transverse arch z-score threshold < - 3 gave sensitivity 100%, NPV: 100%, specificity 76%; aortic isthmus z-score  < - 3: NPV 92%, specificity 62% and DAI > 1.4: NPV 88%, specificity 78%. The size of the distal aortic arch in infants with a common origin of the innominate artery and left common carotid artery who did not require COA repair was similar to the NCOAR cases (p = 0.22). The early postnatal assessment of the size and morphology of the aortic arch can assist in risk stratification for development of neonatal COA. The branching pattern of the head/neck vessels impacts on the size of the distal aortic arch adding to the complexity of predicting COA based on vessel size.