Limitations of Doppler ultrasound in the diagnosis of neonatal coarctation of the aorta.

Blood flow velocities were recorded using Doppler ultrasound in 40 babies aged between 1 day and 4 weeks who had coarctation of the aorta or interruption of the aortic arch. High velocity jets of 3 m/sec or more in the descending aorta were detected in only 3 patients, two of whom had interruption of the aortic arch. There was very poor agreement between upper and lower limb blood pressure difference and Doppler derived peak pressure drop. Doppler ultrasound may provide useful information on coexisting intracardiac abnormalities, but in the presence of ductal patency is of little value in the diagnosis of coarctation itself.