What can indicate a decreased blood flow to the right arm in the case of right subclavian artery stenosis?

A reversal of flow in the right vertebral artery suggests collateral circulation stemming from a significant stenosis or occlusion in the right subclavian artery. When there is a blockage or narrowing in the subclavian artery, the body attempts to compensate for the reduced blood flow to the right arm by redirecting blood flow from alternative pathways. In this case, the vertebral artery can reverse its flow direction to supply the right arm with blood.

This phenomenon occurs due to the anatomy of the circulatory system, where the vertebral arteries can serve as collateral pathways when the usual route via the subclavian artery is compromised. Monitoring the flow direction in the vertebral artery, particularly using Doppler ultrasound, can be an important diagnostic tool for identifying significant stenosis in the subclavian artery and understanding the dynamics of blood flow in such scenarios.

In contrast, the other options do not directly indicate a decrease in blood flow to the right arm due to subclavian artery stenosis. Increased arm pressure could suggest preserved or increased perfusion, rather than decreased flow. A bifid Doppler signal in the right axillary artery may indicate turbulence but does not directly point to decreased flow compared to the normal expected signals. A monophasic Doppler signal in