About the Arteriovenous Malformation Clinic

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​​​​​​​​​​​Toronto Western Hospital | Map iconMaps & Directions
West Wing – 4th Floor​

Hours & Contact

​Monday – Friday
8:00 am – 4:00 pm

Phone: 416 603 5463

What We Do

​Arteriovenous Malformation – or AVM – is a group of abnormal and poorly formed blood vessels (arteries and veins). They can be found anywhere in the body, and because they're so poorly formed, they have a higher rate of bleeding. Brain AVMs are of special concern because of the damage they cause when they bleed.

Though very rare, AVMs affect people of all ages and can be found in children. They're often discovered when they produce symptoms, such as headache or seizures.

Our team is made up of different health care practitioners who can diagnose a brain AVM and determine the best course of treatment. The first step is to get a visual picture of your brain, the blood vessels and the AVM. After the tests are completed, a member of the team will discuss with you and your family or caregiver your treatment options.​​​​​

 Treatment Information

The goal of treatment is to prevent bleeding from the AVM. The bleeding may injure the surrounding brain resulting in a stroke, with possible permanent disability or even death. Given the complexity of some AVMs, some people can have combined treatments. 

Treatment of AVM depends on a variety of factors: your age, your overall health, if you're having symptoms, and the size, location and blood vessels associated with the AVM. Some AVMs require a single treatment, while others are complicated in their location, shape or size and require more than one treatment type. The health care practitioner will go over your options during ​​your visit.

Sometimes AVMs can be tiny or not cause any symptoms. In that case, a periodic test, such as a CTA, may be recommended to check for any changes.

Endovascular Treatment: a neuroradiologist sends a small catheter or tube through an artery in the groin, and it finds its way to an AVM blood vessel. A kind of "glue" is released from the tube and enters the AVM. This substance instantly hardens, cutting off the blood supply – but it doesn't affect blood supply to the brain. 

Surgical Treatment: a neurosurgeon operates and ties off the blood vessels that enter the AVM then removes it. This is a surgical procedure. 

Radiation Treatment: this is also known as Stereotactic Radiosurgery. A narrow x-ray beam is focused on the AVM. The radiation used is quite safe and causes the AVM to close off.​


There are a few different radiological tests that can provide the team with the necessary information needed. A health care practitioner may order more than one of these tests. Some can be completed by your family doctor before your first clinic visit.

 Health Information

Visit our health information section.​​

 Surgical treatment

​If you are interested in viewing the surgical treatment of an AVM, watch our 3 videos about the surgical clipping of an aneurysm.