How is coarctation of the aorta best diagnosed?

The best method for diagnosing coarctation of the aorta involves comparing the blood pressures in the upper and lower extremities. This approach is effective because coarctation can lead to differential blood pressures: typically, the blood pressure in the arms may be significantly higher than that in the legs. This disparity occurs due to the narrowing of the aorta, which restricts blood flow to the lower body, resulting in lower blood pressure readings in the legs compared to the arms.

Using this method can provide critical, immediate evidence of potential coarctation, making it a practical first step in assessment. While the other diagnostic methods, such as echocardiograms, MRIs, and chest X-rays, can be useful for further confirmation and assessment of the condition, they may not offer the same immediate comparison that indicates coarctation as effectively as measuring blood pressures in the extremities does.