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Arteriovenous Malformation (AVM)/Fistula (Vascular Malformation)​

What is Arteriovenous Malformation?

An arteriovenous malformation (AVM) is a congenital defect between the arteries and veins. The condition affects the connection between these blood vessels, and disrupts the flow of blood between them.

Although this defect can occur anywhere, AVMs are most common in the brain or spine.

It is common for people not to know that they have an arteriovenous malformation for many years — or even until they reach adulthood.

You may not know that you have an AVM in your brain until you experience symptoms. A ruptured AVM is a medical emergency.

At UPMC, we are committed to finding the best treatment approach for you, maximizing the benefits of surgery while minimizing the risks.

Possible treatments for an arteriovenous malformation include:

Diagnosing Arteriovenous Malformation

An arteriovenous malformation may not be diagnosed until you experience symptoms, or until the AVM ruptures.

Arteriovenous malformation symptoms

Symptoms of an arteriovenous malformation in the brain include:

  • Seizures
  • Weakness or numbness
  • Headaches
  • Pulsing sound in your head

Symptoms of a ruptured arteriovenous malformation are similar to those of a stroke. They include:

  • Sudden, severe headache
  • Vision loss
  • Difficulty speaking
  • Difficulty understanding others

Tests for diagnosing arteriovenous malformation

Your physician will order imaging studies to confirm that there is an arteriovenous malformation. These tests may include:

  • CT and MRI scans
  • Angiography of the brain

Arteriovenous Malformation Treatments

UPMC neurosurgeons may recommend a combination of surgical and non-surgical approaches to treat arteriovenous malformations.

UPMC offers three treatment options for AVMs, giving patients the best chance for a cure.

Surgery: Microsurgical Resection

Some AVMs can be treated by microsurgical resection, where a doctor will:

  • Perform a small craniotomy 
  • Use a microscope to guide the complete removal of the AVM
  • Coagulate any feeding arteries

Gamma Knife® radiosurgery

Gamma Knife radiosurgery is a painless treatment that uses hundreds of highly focused radiation beams to target tumors and lesions within the brain, with no surgical incision.

Gamma Knife treatment is a minimally invasive management option especially for deep-seated and high surgical risk AVMs. It can be used as the primary treatment or following surgery or embolization to treat any remaining AVM.

As the nation's leading provider of Gamma Knife procedures, UPMC has treated more than 12,000 patients with tumors, vascular malformations, pain, and other functional problems.


Endovascular embolization is a minimally invasive procedure that involves the threading of a small catheter or tube through a blood vessel in the groin, which is then navigated to blood vessels in the brain to block blood flow.

Small coils or detachable silicon balloons are guided through the arteries to stop the abnormal blood flow to the AVM.