What is the expected change in venous outflow when an arteriovenous fistula is present?

The presence of an arteriovenous fistula creates a direct connection between an artery and a vein, bypassing the normal microcirculatory beds. This physiological change affects venous outflow significantly.

When an arteriovenous fistula is created, the arterial pressure is transmitted directly into the venous system. As a result, the veins experience increased blood flow volume and velocity, leading to pulsatile flow characteristics. The increased arterial blood volume entering the venous system means that venous outflow is not only increased but also exhibits pulsatility, reflecting the rhythmic changes in arterial pressure and flow.

This increased and pulsatile venous outflow is distinct in comparison to the normal venous flow, which is typically steady and lower in volume. Therefore, in the context of an arteriovenous fistula, the flow changes observed in the veins are significant and directly linked to the altered hemodynamics introduced by the fistula itself. The other options do not accurately capture the dynamic nature of venous flow alterations seen in this context.