What indicates a potential subclavian artery stenosis greater than 50%?

The identification of potential subclavian artery stenosis greater than 50% is typically assessed using blood pressure measurements. In this context, a difference in blood pressures between the arms can indicate the presence of significant stenosis.

A pressure difference of 15-20 mmHg suggests that there is likely a considerable obstruction in the subclavian artery, which can lead to a reduction in blood flow. When the stenosis is more significant than 50%, the hemodynamic changes become more pronounced, and the blood pressure reading will reflect that through the increased difference between the two arms.

This specific range of 15-20 mmHg is clinically significant as it helps to differentiate between mild or moderate stenosis and more pronounced cases, where interventions may be necessary. Values below this range may not indicate significant stenosis, hence demonstrating why the other choices would not be appropriate indicators for a stenosis greater than 50%.

Utilizing the 15-20 mmHg difference as a threshold allows clinicians to make informed decisions regarding further diagnostic imaging or therapeutic options for patients suspected of having subclavian artery stenosis.