Severe pulmonary hypertension as a cause of reverse aortic arch flow in the neonate: report of two cases.

We describe two newborn infants with severe pulmonary hypertension and circulatory collapse. In both cases, pulsed and color flow Doppler studies showed systolic and diastolic reversal of flow in the transverse aortic arch to the level of the innominate artery. No associated cardiac or noncardiac anomalies could explain the reverse flow in the aortic arch. Severe pulmonary hypertension and low left ventricular output were thought to be responsible for the Doppler findings. Reversal of the aortic arch flow in the newborn with pulmonary hypertension may be associated with a poor prognosis, and early consideration of extracorporeal membrane oxygenation in such patients may be indicated.