What is one of the key signs of coarctation of the aorta?

In coarctation of the aorta, there is a narrowing of the aorta that typically occurs just distal to the left subclavian artery. This condition leads to a significant difference in blood pressure between the upper and lower parts of the body. Specifically, the blood pressure in the arms is usually higher than that in the legs.

When examining a patient with coarctation, you would expect the blood pressure in the legs to be lower than that in the arms due to the obstruction caused by the coarctation. This disparity is a key clinical finding and helps to confirm the diagnosis of coarctation of the aorta.

Monitoring the blood pressure in both the arms and legs, therefore, is crucial in identifying this condition, and a lower blood pressure in the legs serves as an indicator of the obstructive nature of the aortic narrowing. This clinical sign is used to differentiate coarctation from other cardiovascular issues that may not exhibit such significant differential blood pressures between the two regions.