Arteriovenous (AV) fistula: What is it?

A-V fistula

A fistula is an abnormal connection between two parts of the body. An arteriovenous (AV) fistula refers to an abnormal connection between an artery and a vein.

An arteriovenous (AV) fistula is an abnormal passageway between an artery and a vein. Although it most often occurs in the legs or arms, an AV fistula can occur anywhere in the body, including the brain. An AV fistula may also be created surgically to provide access for hemodialysis in people with end-stage kidney failure.

Normally, your blood flows from arteries through capillaries and back to your heart in veins. When an AV fistula is present, blood flows directly from an artery into a vein, bypassing the capillaries. If the volume of diverted blood flow is large, tissues downstream receive less blood supply. In addition, heart failure may occur due to the increased volume of blood returned to the heart.

A doctor may suspect an AV fistula by an abnormal sound (bruit) heard over the artery with a stethoscope. The sound is due to turbulent blood flow between the artery and the vein. Small fistulas following injury sometimes close without treatment. But larger fistulas usually require treatment, which may include:

• Endovascular coils inserted into the fistula to close it
• Surgery to block the abnormal channel