A proximal stenosis can cause retrograde flow in the downstream artery due to which mechanism?

A proximal stenosis can cause retrograde flow in the downstream artery due to which mechanism?

• A. Pressure drop proximal to stenosis
• B. Pressure rise distal to stenosis
• C. Loss of energy due to turbulence
• D. Increased volume flow

Answer: (A)

When a vessel has a proximal narrowing, it acts like a bottleneck that increases resistance to forward flow. As blood is driven toward and through the narrow segment, energy losses cause the static pressure just upstream of the stenosis to fall. If the pressure downstream remains relatively higher because of the network it feeds, the pressure gradient can reverse, so blood flows from the downstream side back toward the stenosis. In short, the drop in pressure on the upstream (proximal) side creates a reversed pressure gradient that drives retrograde flow in the downstream artery.

When a vessel has a proximal narrowing, it acts like a bottleneck that increases resistance to forward flow. As blood is driven toward and through the narrow segment, energy losses cause the static pressure just upstream of the stenosis to fall. If the pressure downstream remains relatively higher because of the network it feeds, the pressure gradient can reverse, so blood flows from the downstream side back toward the stenosis. In short, the drop in pressure on the upstream (proximal) side creates a reversed pressure gradient that drives retrograde flow in the downstream artery.