Arteriovenous Fistula 

An arteriovenous fistula occurs when blood flows between an artery and a vein, bypassing the capillaries. 
Arteriovenous fistula (AVF) is a condition characterized by an abnormal connection between an artery and a vein. Typically, blood flows through the arteries, into the capillaries and then into the veins. In a person with an AVF, the blood skips the capillaries completely, instead flowing directly into the veins from the arteries. This reduces the amount of blood the capillaries receive, which can lead to serious medical complications since the capillaries use the blood to deliver nutrients and oxygen to tissues in the body. An AVF is most common in the legs, head, neck, spine and liver, although it can occur anywhere in the body. 

Causes of Arteriovenous Fistulas 

An arteriovenous fistula can be congenital (present at birth) or acquired:  

• Congenital arteriovenous fistulas are rare, and researchers are still trying to discover why some babies develop this condition. However, they have found a link between genetic conditions such as Osler-Weber-Rendu disease and AVFs. 
• Acquired arteriovenous fistulas often occur when there is trauma to the body’s tissue, such as a stabbing wound or gunshot injury. Some patients with late-stage kidney disease may have a fistula surgically created to help with dialysis. 

Symptoms of Arteriovenous Fistulas 

Small arteriovenous fistulas often don’t produce any symptoms. Those with larger AVFs may experience: 

• Swelling of the arms or legs 
• Fatigue 
• Bulging veins that have a purplish tinge (similar to varicose veins) 
• Lightheadedness and/or fainting 

Another symptom that can result from an AVF is decreased blood pressure, which causes the heart to pump much faster and forcefully than normal to compensate. Eventually, this increased output can lead to heart failure.  

Diagnosing Arteriovenous Fistulas 

To diagnose an arteriovenous fistula, your doctor will use a stethoscope to listen to the way your blood is flowing through your arms and legs. AVF blood flow delivers a distinctive humming sound that differentiates itself from normal blood flow.  

Next, your doctor will likely order specific imaging tests to confirm the diagnosis. These include: 

• A duplex ultrasound 
• A computed tomography (CT) angiogram 
• A magnetic resonance angiography (MRA) 

Treatment for Arteriovenous Fistulas 

Tampa General Hospital offers numerous treatments for arteriovenous fistulas. The specialists in our Heart & Vascular Institute will determine which option is best for your needs. Medical monitoring is often the first course of action for small fistulas that are not causing symptoms. Larger AVFs may require: 

• Endovascular embolization 
• Microsurgery 
• Stereotactic radiosurgery