What is a likely cause of high diastolic flow in the proximal CFA and increased reversed flow in the distal CFA?

High diastolic flow in the proximal common femoral artery (CFA) accompanied by increased reversed flow in the distal CFA is often indicative of an arteriovenous fistula (AVF). In an AVF, there is an abnormal connection between an artery and a vein that allows high-volume arterial blood to flow directly into the venous system. This shunting of blood increases the diastolic flow in the proximal CFA due to the increase in blood volume and pressure from the arterial side.

The reversed flow in the distal CFA can occur because the pressure in the vein is elevated due to the increased volume from the fistula, leading to altered flow dynamics in the surrounding arterial structures. The complex interactions between the arterial and venous systems in the presence of an AVF result in these characteristic flow patterns, setting this choice apart from the others.

Other conditions, such as carotid artery stenosis, aneurysms, and aortic dissections, typically present with different flow characteristics and do not generally produce the same flow dynamics observed with an AVF. For instance, carotid artery stenosis primarily affects the carotid circulation and does not directly lead to this specific pattern in the CFA. Aneurysms would more likely result in localized