Arteriovenous fistula

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC

Arteriovenous fistula
Synonyms	AV fistula
Pronounce	N/A
Specialty	N/A
Symptoms	Swelling, pain, bruit, heart failure
Complications	Aneurysm, thrombosis, infection
Onset	Congenital or acquired
Duration	Chronic
Types	N/A
Causes	Trauma, surgery, congenital
Risks	Hypertension, heart failure, bleeding
Diagnosis	Ultrasound, angiography
Differential diagnosis	Arteriovenous malformation, varicose veins
Prevention	N/A
Treatment	Surgery, endovascular therapy
Medication	N/A
Prognosis	Variable, depending on size and location
Frequency	Rare
Deaths	N/A

Arteriovenous Fistula

An arteriovenous fistula (AVF) is an abnormal connection between an artery and a vein. This condition can occur naturally or be surgically created for medical purposes, such as for hemodialysis access in patients with chronic kidney disease.

Diagram of an arteriovenous fistula

Pathophysiology

In a normal circulatory system, blood flows from arteries to capillaries and then to veins. An arteriovenous fistula bypasses the capillary system, allowing blood to flow directly from an artery into a vein. This can lead to various physiological changes, including increased blood flow and pressure in the affected vein, which can cause the vein to enlarge and become more prominent.

Causes

Arteriovenous fistulas can be congenital or acquired. Congenital AVFs are present at birth and may be part of a vascular malformation. Acquired AVFs can result from trauma, surgical procedures, or diseases that affect the blood vessels.

Congenital

Congenital AVFs are often associated with conditions such as Parkes Weber syndrome and Hereditary hemorrhagic telangiectasia. These conditions involve abnormal blood vessel development and can lead to multiple AVFs throughout the body.

Acquired

Acquired AVFs can occur due to:

• Trauma: Penetrating injuries or fractures can lead to the formation of an AVF.
• Surgical procedures: Intentional creation of an AVF is common in patients requiring long-term hemodialysis.
• Inflammatory diseases: Conditions such as vasculitis can damage blood vessels and lead to AVF formation.

Clinical Presentation

The symptoms of an arteriovenous fistula depend on its size, location, and the amount of blood flow through it. Common symptoms include:

• Swelling: Due to increased blood flow and pressure in the affected vein.
• Bruit: A whooshing sound heard over the fistula due to turbulent blood flow.
• Warmth: The area over the fistula may feel warmer than surrounding tissues.
• Heart failure: Large AVFs can increase cardiac output and lead to heart failure.

Diagnosis

Diagnosis of an arteriovenous fistula typically involves:

• Physical examination: Detection of a bruit or thrill over the affected area.
• Imaging studies: Ultrasound, CT angiography, or MRI can visualize the fistula and assess its size and impact on surrounding structures.

Treatment

Treatment of an arteriovenous fistula depends on its cause and symptoms. Options include:

• Observation: Small, asymptomatic AVFs may not require treatment.
• Surgical repair: Ligation or resection of the fistula may be necessary for symptomatic or large AVFs.
• Endovascular techniques: Minimally invasive procedures such as embolization can be used to close the fistula.

Surgical Creation for Hemodialysis

In patients with chronic kidney disease, an arteriovenous fistula is often surgically created to provide reliable vascular access for hemodialysis. This involves connecting an artery to a vein, usually in the arm, to allow for repeated needle insertions and efficient blood flow during dialysis sessions.

See also

• Vascular malformation
• Hemodialysis
• Chronic kidney disease
• Vasculitis