Arteriovenous Fistula

What is an Arteriovenous Fistula?

When blood flows directly from arteries to veins and bypasses the capillaries, it’s referred to as arteriovenous fistula. Blood normally goes from arteries to veins through tiny blood vessels called capillaries. The abnormal connection is often congenital, although it may also be caused by trauma or created surgically.

What are the Symptoms of Arteriovenous Fistula?

There are typically no noticeable symptoms associated with small arteriovenous fistulas that may naturally occur in the legs, kidneys, arms, or other parts of the body, including the brain. In some cases, the restricted blood flow may reduce blood flow to nearby limbs.

Symptoms include

  • Bulging, purplish veins
  • Arm or leg swelling
  • Low blood pressure
  • Increased fatigue
  • Blue areas of skin
  • Coughing blood (pulmonary arteriovenous fistula affecting lungs)
  • Internal bleeding in digestive tract (gastrointestinal arteriovenous fistula)

Arteriovenous Fistulas Causes

Arteriovenous fistulas may be caused by genetic conditions, an injury, or by surgery.

Genetic conditions

Arteriovenous fistulas can occur in the lungs due to the genetic disease Osler-Weber-Rendu disease. Also called hereditary hemorrhagic telangiectasis, blood vessels through your body develop abnormally, especially in the lungs.

Congenital conditions

It’s unclear why some people are born with an arteriovenous fistula. For unknown reasons, the arteries and veins fail to develop correctly in the womb.

Skin-piercing injuries

If you receive a piercing injury where a vein and artery are side by side, you can develop an arteriovenous fistula. Gunshots and stab wounds place you at high risk of developing a fistula.

Surgical creation (AV fistula procedure)

Doctors will create an arteriovenous fistula to improve delivery of dialysis to people with late-stage kidney failure. Veins can be scarred or destroyed from too many dialysis needle insertions. The new fistula increases the vein’s width and improves blood flow by connecting it to an artery. Surgically created arteriovenous fistulas are usually created in the forearm.

Cardiac catheterization

While rare, an arteriovenous fistula may be created as a complication of this procedure. In the same way the arteriovenous fistula is created deliberately, the needle used in the cardiac catheterization may cross an artery and a vein, widening the artery and causing the fistula.

How is an Arteriovenous Fistula Treated?

Arteriovenous fistulas present in children are often monitored periodically. The same is true if smaller fistulas are discovered. When an arteriovenous fistula is purposely created, as is the case during hemodialysis for patients with kidney functioning below 10-15 percent, patients are monitored for complications.

Non-surgical treatment

  • Corticosteroid injections
  • Elastic support hose (for AFs affecting lower extremities)
  • Alcohol sclerotherapy (to shrink the AF)
  • Photodynamic therapy (photosensitizing agent is exposed to a specific wavelength of light)
  • Sclerotherapy (injection of a salt solution into veins)

Often occurring within the legs, arteriovenous fistula results in a reduced blood supply for tissues below where it’s located. AFs are sometimes surgically created for patients on dialysis or those with chronic kidney conditions. Patients who have had a cardiac catheterization, involving the placement of a flexible tube in the heart, may also develop an arteriovenous fistula. There are no preventative measures.

Arteriovenous Fistulas Prevention

To prevent arteriovenous fistula, you should avoid skin-piercing injuries on the job with the use of appropriate personal protective equipment, such as protective vests, hard hats, gloves, shoes, and so on.

Young girls should not become pregnant. Although obstetric fistulas occur in pregnant women of all ages, young girls are at a much higher risk of arteriovenous fistulas due to the physical strain of childbearing. Women in poor nations such as Sub-Saharan Africa suffer from a lack of access to obstetric care that would prevent the formation of an arteriovenous fistula.