Arteriovenous Fistula

An arteriovenous fistula is a medical condition where an artery and vein connect directly, causing blood to flow between them. It can happen at virtually any place in your body where an artery and vein are close together, especially inside of your organs and limbs (arms and legs). Depending on where fistulas are, why they happened and their size, they can be harmless (or even helpful when there’s a medical reason to create one), or they can be a major health issue and permanently damage your heart.

Who does it affect?

Arteriovenous fistulas (pronounced “are-tee-re-oh-vee-nus fis-tew-las”) can happen to anyone at any age, especially when they happen because of injuries. Certain types of fistulas are more common in certain groups of people, usually because of their life circumstances (see the Causes and Symptoms section for more details).

There are two different terms for more than one fistula, but both are correct. You can use either “fistulas” or “fistulae” (pronounced “fis-tew-lay”).

How common is this condition?

Arteriovenous fistulas are very common overall, but some types aren’t. The most common types of arteriovenous fistulas are those that are medically created for people needing dialysis. The least common arteriovenous fistulas are those you have when you’re born.

Arteriovenous fistulas are very common for people who need dialysis. The national goal, set by a partnership between the Centers for Medicare and Medicaid Services and other groups, is for 68% or more of people on dialysis to have an arteriovenous fistula.

What happens with an arteriovenous fistula, and how does it affect my body?

Your body uses different types of blood vessels for different purposes. These include:

• Arteries: These large vessels carry blood from your heart to the rest of your body.
• Veins: These large vessels return blood from your body back to your heart.
• Capillaries: These very small vessels form networks throughout your body.

Under normal circumstances, your arteries and veins don’t connect directly. Instead, blood first goes from your arteries into a network of smaller blood vessels called capillaries. Arteries and veins are like highways through a major city, providing plenty of room for blood to move quickly. Capillaries are like the city streets, providing blood flow to all tissues, even those farthest away from major blood vessels.

A fistula between an artery and a vein means that blood can move directly between them. Your arteries have higher pressure in them because of the pumping force of your heart. That can disrupt the blood flow in the connected vein and keep it from flowing in the direction of your heart. Your arteries can handle the higher pressure, but your veins can’t. That can cause them to stretch and swell.

If a fistula is in a certain place or it’s very large, your heart will pump harder to try to force blood to flow correctly. Over time, the extra work strains your heart and causes it to fail.

Fistulas can also cause problems when they happen in vital organs, including:

• Brain: Dural and pial arteriovenous fistulas.
• Heart: Coronary arteriovenous fistula.
• Spine: Spinal dural arteriovenous fistula.
• Kidneys: Renal arteriovenous fistula.