Overview
An arteriovenous fistula (AVF) is an abnormal connection between an artery and a vein, bypassing the normal pathway of blood flow through capillaries. This direct connection can lead to less blood flow to the tissues below the avoided capillaries. AVFs can occur in various parts of the body, most commonly in the legs, and can be surgically created for dialysis in people with severe kidney disease. Symptoms of AVFs depend on their location and size, with small untreated fistulas often being asymptomatic and requiring only monitoring by a healthcare provider. Larger fistulas may cause symptoms such as swelling, pain, or skin discoloration.
Understanding the disease
Symptoms
Symptoms of arteriovenous fistulas depend on where they form in the body. Small arteriovenous fistulas in the legs, arms, lungs, kidneys, or brain often won't have any signs or symptoms. Small arteriovenous fistulas usually don't need treatment other than monitoring by a health care provider. Large arteriovenous fistulas may cause signs and symptoms, including:
- Purplish, bulging veins seen through the skin, similar to varicose veins
- Swelling in the arms or legs
- Decreased blood pressure
- Fatigue
- Heart failure In serious cases, arteriovenous fistulas can cause:
- Pale gray or blue lips or fingernails due to lack of blood flow (cyanosis)
- Fingertips to spread out and become rounder than normal (clubbing)
- Coughing up blood
- Gastrointestinal (GI) bleeding, in the case of an arteriovenous fistula in the digestive tract It's important to see a healthcare provider if you notice any symptoms of an arteriovenous fistula.
Risk Factors
Risk factors for developing arteriovenous fistula may include older age, female sex, genetic or congenital conditions, cardiac catheterization, certain medications, high blood pressure, and increased body mass index (BMI).
Development
Arteriovenous fistulas can develop due to several reasons:
- Injuries: Arteriovenous fistulas may result from a gunshot or stab wound that occurs on a part of the body where a vein and artery are side by side.
- Congenital conditions: In some babies, the arteries and veins don't develop properly in the womb, leading to congenital arteriovenous fistulas.
- Genetic conditions: Arteriovenous fistulas in the lungs (pulmonary arteriovenous fistulas) can be caused by a genetic disease that causes irregular blood vessels throughout the body, but especially in the lungs, such as Osler-Weber-Rendu disease.
- Dialysis-related surgery: People who have late-stage kidney failure may have a surgery to create an arteriovenous fistula in the forearm to make it easier to perform dialysis. It's important to note that certain genetic or congenital conditions can increase the risk of arteriovenous fistulas. Other potential risk factors include older age and female sex. While the document mentions the risk factors, it does not provide information on the exact mechanisms through which these fistulas develop in all cases.
Assessment and Diagnosis
Triage
If you have signs and symptoms of an arteriovenous fistula, you should make an appointment to see your health care provider. Early detection of an arteriovenous fistula may make the condition easier to treat and reduce the risk of developing complications, including blood clots or heart failure. Signs and symptoms of arteriovenous fistulas may include purplish, bulging veins seen through the skin, swelling in the arms or legs, decreased blood pressure, fatigue, heart failure, and pale gray or blue lips or fingernails due to lack of blood flow (cyanosis).
Diagnosis
To diagnose an arteriovenous fistula, a health care provider may use a stethoscope to listen to the blood flow in the arms and legs, which makes a sound like humming. Other diagnostic tests to confirm the diagnosis may include duplex ultrasound, computerized tomography (CT) angiogram, and magnetic resonance imaging (MRI) for dural arteriovenous fistulas. For dural arteriovenous fistulas, initial imaging may include noncontrast head CT and MRI, while CT head scans and MRIs can show the shape and extent of the fistula, detect any micro-hemorrhages, and determine the impact of any abnormal blood vessel structures related to the fistula. Magnetic resonance angiography (MRA) may also be done if there are signs of an arteriovenous fistula deep under the skin. Treatment options for arteriovenous fistulas may include ultrasound-guided compression, angiography, and surgery to block or disconnect the fistula.
Management and Treatment
Complications
Potential complications of arteriovenous fistula include heart failure, which is the most serious complication of large arteriovenous fistulas. Other complications may be serious as well. Left untreated, an arteriovenous fistula can cause these complications.
Treatment
Treatment for arteriovenous fistulas depends on the location, size, and symptoms of the fistula. For small and asymptomatic fistulas, treatment may involve monitoring by a healthcare provider. However, for large fistulas or those causing symptoms, treatment options may include:
- Compression: Wearing compression stockings or bandages can help reduce swelling and improve blood flow.
- Catheter-based procedures: These may involve embolization, in which a catheter is used to block off the fistula with a material like a platinum coil or glue.
- Surgery: For some cases of arteriovenous fistula, surgical intervention may be necessary to remove or repair the abnormal connection between the artery and vein. It's important to consult with a healthcare professional for a proper evaluation and personalized treatment plan.
Preparing for medical consultation
To prepare for an appointment for an arteriovenous fistula, you should:
- Write down any symptoms you're experiencing, including those that may seem unrelated to an arteriovenous fistula.
- Note down key personal information, such as a family history of arteriovenous fistulas or other blood vessel diseases, and any previous piercing injuries.
- Bring along any recent brain scans on a CD to your appointment.
- Prepare a list of questions to ask your healthcare provider. Examples of questions include:
- What's the most likely cause of my symptoms?
- Are there any other possible causes for my symptoms?
- What kinds of tests will I need?
- What treatments are available, and which do you recommend?
- What's an appropriate level of physical activity?
- How can I best manage my other health conditions together?
- Should my children or other biological relatives be screened for this condition?
- Consider bringing a family member or friend along for support, as they may remember something you missed or forgot during the appointment. Remember to provide your healthcare provider with as much detail as possible about your symptoms, medical history, and any concerns you may have. This will help them make the most accurate diagnosis and recommend the best course of treatment for you.