Noninvasive diagnosis of coarctation of the aorta in the presence of a patent ductus arteriosus.

Although the diagnosis of coarctation of the aorta in the full-term neonate is straightforward when no ductus arteriosus is present, identification of coarctation of the aorta when a ductus arteriosus is patent can be difficult. A patent ductus arteriosus is frequently found in association with coarctation of the aorta, and it may remain open for many days. Thus a reliable method to rapidly identify coarctation of the aorta would obviate the need for cardiac catheterization or an in-hospital observation period until the ductus arteriosus closes spontaneously. Echocardiographic/Doppler examination of 19 consecutive full-term neonates with a birth weight of > 2.9 kg, who subsequently underwent surgical repair of coarctation of the aorta, were reviewed. Fourteen patients with similar weights, a patent ductus arteriosus, and a normal aortic arch were matched for comparison. Based on the findings, the following diagnostic criteria for coarctation of the aorta are suggested: isthmic diameter less than or equal to 3 mm or isthmus equal to 4 mm together with the Doppler finding of continuous antegrade flow in the isthmal segment. Coarctation of the aorta in the full-term neonate can be ruled out when the flow within the ductus arteriosus is exclusively from aorta to pulmonary artery or when the isthmic diameter is equal to or greater than 5 mm.