Arteriovenous (AV) fistula is an abnormal connection between an artery and a vein. Normally, blood flows from the arteries to the capillaries to the veins. Nutrients and oxygen in the blood travel from the capillaries to tissues in the body. With an arteriovenous fistula, blood flows directly from an artery into a vein, bypassing some capillaries. When this happens, tissues below the bypassed capillaries receive a diminished blood supply.

Arteriovenous fistulas usually occur in the legs, but can develop anywhere in the body. Arteriovenous fistulas are often surgically created for use in dialysis in people with severe kidney disease. A large untreated arteriovenous fistula can lead to serious complications. If you've had an arteriovenous fistula created for dialysis, you will be monitored for complications.


Small arteriovenous fistulas in the legs, arms, lungs, kidneys or brain do not have any signs or symptoms and usually do not  need treatment other than monitoring by the doctor. Larger arteriovenous fistulas may cause signs and symptoms.

Arteriovenous fistula signs and symptoms may include:

  • Swelling in the arms or legs,
  • Purple bulging veins that you can see through the skin, similar to varicose veins,
  • Decreased blood pressure,
  • Fatigue,
  • Heart failure.

An arteriovenous fistula in the lungs (pulmonary arteriovenous fistula) is a serious condition and can cause:

  • Blue skin,
  • Clubbing of fingers,
  • Coughing up blood.

An arteriovenous fistula in the gastrointestinal tract can cause bleeding in the digestive tract.


Causes of arteriovenous fistulas include:

  • Cardiac catheterization,
  • Injuries that pierce the skin,
  • Congenital arteriovenous fistula,
  • Genetic conditions,
  • Surgical creation (AV fistula procedure).

Creating an arteriovenous fistula widens the vein by connecting it to a nearby artery, making it easier to insert a needle for dialysis and causing blood to flow faster. This AV fistula is usually created in the forearm.

Risk factors

The risk factors are related to the causes, so care must be taken to eliminate them when inserting needles or exert caution to protect against injuries.


Left untreated, an arteriovenous fistula can cause complications, some of which can be serious. These include:

  • Heart failure,
  • Blood clots,
  • Leg pain,
  • Bleeding.


To prevent arteriovenous fistulas people have to be careful with injuries and medical staff with needles, scalps and scissors.