What indicates flow in an artery distal to a total occlusion?

When assessing blood flow in an artery distal to a total occlusion, the presence of collaterals is a significant indication. Collateral circulation develops as compensatory pathways when the primary artery is obstructed. These alternative pathways may not have the same caliber or pulsatile characteristics as the main artery, leading to a flow that is often dampened.

This dampened signal occurs because collateral vessels tend to be smaller and may not deliver blood with the same pressure or speed as the main vessel, resulting in a less distinct pulsatile flow. The collaterals redirect some blood flow around the obstruction, providing vital circulation to the tissues downstream.

In contrast, the presence of normal pulsatile flow would indicate an unobstructed artery and the restoration of direct flow, which contradicts the concept of a total occlusion. Similarly, increased turbulence without direction would suggest some form of disturbed flow or mixing, which does not equate to functional blood supply. Therefore, the identifying characteristic of flow in the presence of a total occlusion is indeed the dampened signal created by collaterals.