An arteriovenous fistula is when an artery and vein connect directly, allowing blood to flow incorrectly. These can be surgically created for people who need dialysis care. They can also happen because of injuries or form in the womb before a person is born. While they’re sometimes dangerous, they’re usually treatable and often curable.
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.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
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”).
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.
Your body uses different types of blood vessels for different purposes. These include:
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:
These can vary, depending on their location. The most common symptoms include:
When a fistula on one of your limbs is very large, areas farther away from the heart than the fistula may develop symptoms of ischemia. This condition (pronounced “iss-key-me-uh”) is when parts of your body don’t have enough blood flow.
If the lack of blood flow is severe enough, it can damage those areas, or the cells in those areas may even start to die. This is also sometimes called “steal syndrome” because blood is “stolen” from the affected area because the fistula diverts blood away.
The symptoms of ischemia like this include:
Large arteriovenous fistulas can also cause problems for your heart. Because blood isn’t flowing correctly around the fistula, your heart tries to compensate by pumping harder. Over time, that damages your heart and causes heart failure. Symptoms of heart failure like this include:
Congenital arteriovenous fistulas often have different symptoms because of how they happen. These form as you develop in the womb, which means they can affect a larger area if that area doesn’t develop as expected.
Congenital arteriovenous fistulas will often affect how the affected body part grows. When it’s on your arm or leg, that limb may have a greater muscle mass or longer bones because of the unusual blood flow patterns. A person may also have clubbing, a swelling in the fingertips (where the fingernails become very soft, bulge upward in the middle and curve down near their fingertip). In other cases, they may not have enough blood flow to the affected limb, which will turn blue farther down because of lack of blood flow.
The three main causes of arteriovenous fistula are:
In rarer cases, arteriovenous fistulas can happen because of conditions like cancer, certain types of infections or when an artery develops an aneurysm (a weakness in your artery wall that bulges out and presses against a nearby vein).
Arteriovenous fistulas aren’t contagious, which means you can’t spread them to or catch them from other people.
Your healthcare provider can diagnose an arteriovenous fistula with a variety of approaches, including a physical examination and diagnostic imaging. Other tests might happen, but these are most likely related to finding the underlying cause of an arteriovenous fistula.
During a physical examination, your healthcare provider will do the following:
The most likely tests include at least one type of imaging. The available options include:
Most arteriovenous fistulas are often curable, depending on the cause, size and where they are. While it’s much harder to cure congenital arteriovenous fistulas, it’s usually possible to treat them and manage any related issues or complications.
Many people with this condition may not need treatment as a first option. The main reasons why treatment becomes necessary include:
The most common means of treating or curing an arteriovenous fistula include:
Treating an arteriovenous fistula often involves medication as well. In cases where a fistula creates a risk of a blood clot forming, blood-thinning medications are often helpful. These medications prevent clots from blocking blood vessels where they form or from breaking loose and traveling to another part of your body, where they can cause deadly conditions like heart attack, stroke or pulmonary embolism.
Dialysis-related fistulas aren’t usually the focus of treatment unless something goes wrong with them. In those cases, surgery is often an option to repair them.
The complications or side effects from treatments depend on the specific treatments and the location and size of the fistula. Your healthcare provider is the best person to explain the possibilities to you and help you understand what you can do to reduce your risk of these problems.
It isn’t possible to diagnose an arteriovenous fistula on your own. Many of the symptoms of this condition also happen with other, more serious conditions like aneurysms or blood clots. Because of this, you shouldn’t try to self-diagnose and treat them on your own. If your healthcare provider diagnoses you with this condition, they’re the best person to advise you on how to care for it yourself.
The time it takes you to feel better and fully recover depends on the treatment used, as well as the size and location of the fistula. Your healthcare provider is the best person to tell you what you should expect regarding your symptoms diminishing and when you should recover.
Arteriovenous fistulas aren’t preventable because the most common causes are injuries (which are almost always unpredictable), or they form before you’re born. When they happen in connection with dialysis, they’re intentional, and your medical provider will create one to help make your dialysis care more effective.
The outlook for arteriovenous fistulas depends on their size, location and cause. Smaller fistulas or those in certain places often don’t need treatment, and many people will only notice mild symptoms or have no symptoms at all. Larger fistulas or those that happen in critical places are the ones that can cause the most problems. Your healthcare provider is the best person to tell you the outlook and what you can expect with these.
Congenital fistulas often have a good prognosis and outlook if they aren’t in a critical location. When they’re in a dangerous spot or very severe, they can cause serious complications or even death.
Dialysis-related fistulas usually don’t cause any problems. When they have side effects, your healthcare provider can often treat those effects or help you find alternatives that will work better. They may do a follow-up surgery to repair the fistula or return the affected blood vessels to their original shape and location in more severe cases.
When they aren’t serious, arteriovenous fistulas can last your entire life and cause few or no problems. When fistulas are more serious, it’s important to see your healthcare provider. Quick diagnosis and treatment are essential, especially with larger fistulas. That’s because larger fistulas can cause your heart to strain until you develop heart failure. While repairing a fistula often allows your heart to return to normal even after heart failure starts, this doesn’t always happen. For that reason, it’s best to treat arteriovenous fistulas sooner rather than later.
If you have an arteriovenous fistula with mild or no symptoms, the best thing you can do is watch for any changes. If you have a fistula with symptoms, your healthcare provider can guide you on what to do to care for it and problems for which to watch. Some people may benefit from wearing compression garments, which put light pressure on the entire area of your body and help push fluid out of the area within the garment.
You should call or see your healthcare provider if you notice any changes in your symptoms, especially changes that are new, get worse or that start to affect your routine or activities.
Key symptoms to watch for include:
You should call your provider if you notice any changes near an arteriovenous fistula that you have for dialysis reasons. Changes that are especially important to catch early include:
You should go to the emergency room if you have any symptoms of internal bleeding or symptoms that might mean you’re not getting enough blood flow to part of your body, especially a hand or foot.
Symptoms like these include:
Your healthcare provider can also tell you other signs and symptoms to look for that might mean you need emergency medical attention. They can also tailor that information to fit your specific situation, including your health history, other medical conditions you might have and the treatments you’ve received in the past.
A note from Cleveland Clinic
An arteriovenous fistula is a condition that can have little to no effect on your life, or it can cause significant problems. It’s also extremely common for people with kidney disease or kidney failure to have an arteriovenous fistula created surgically, as fistulas can be very helpful for people who need regular dialysis. However, they can cause serious complications or even death in rare cases. Fortunately, advances in modern imaging and medical care mean this condition is often treatable or even curable.
Last reviewed by a Cleveland Clinic medical professional on 07/05/2022.
Learn more about our editorial process.