In a term neonate with a differential blood pressure of 20 mmHg between the upper and lower extremities, which vascular anomaly is most suspected?

• A. Coarctation of the aorta
• B. Tetralogy of Fallot
• C. Transposition of the great arteries
• D. Pulmonary stenosis

Answer: (A)

When the blood pressure differs between the arms and legs in a term neonate, it points to a blockage in the aorta beyond where the arteries to the arms branch off. The most typical culprit is coarctation of the aorta, where narrowing of the aorta reduces blood flow to the lower body. This causes the upper-extremity systolic pressure to stay higher while the legs have a lower pressure, and femoral pulses may be weak or delayed.

This pattern isn’t usually seen with the other congenital heart lesions. Tetralogy of Fallot mainly causes cyanosis from a right-to-left shunt and doesn’t classically produce a significant, consistent upper-limb versus lower-limb BP difference. Transposition of the great arteries creates two parallel circuits with profound hypoxemia rather than a straightforward BP gradient between limbs. Pulmonary stenosis can limit pulmonary blood flow and cause a murmur, but it doesn’t present with the characteristic systemic BP drop from arms to legs.

If coarctation is suspected, echocardiography confirms the diagnosis, and management may involve maintaining ductal patency with prostaglandin E1 in ductal-dependent cases while planning definitive repair.