Our UHN programs and services are among the most advanced in the world. We have grouped our physicians, staff, services and resources into 10 medical programs to meet the needs of our patients and help us make the most of our resources.
University Health Network is a health care and medical research organization in Toronto, Ontario, Canada. The scope of research and complexity of cases at UHN has made us a national and international source for discovery, education and patient care.
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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.
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.
If you are interested in viewing the surgical treatment of an AVM,
watch our 3 videos about the surgical clipping of an aneurysm.
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.
Your first appointment can take 2 hours or more. At this time we will review with you your test results and answer all questions that you have. We may also arrange to have some tests done during your clinic visit, such as a CT Scan. Other tests that you may require will be discussed with you during this time. Remember to bring your questions with you.
Follow-up appointments usually take 15 to 45 minutes. During this visit, we may discuss treatment results and your treatment options. You may meet various members of the team.
Learn more about
what you can expect when you have a clinic appointment.
Visit our health information section.
Why some people develop AVMs is still unknown – but we know how to treat them, and we have the experts to care for you. They include:
Our clinical team is highly specialized, not only treating some of the most complex cases of AVMs in the country, but pioneering treatments as well.
Through our partnership with UHN Foundation, we are proud to offer our patients modern, state-of-the-art equipment, which is necessary for both diagnosing and treating AVM.
Our team is affiliated with the University of Toronto's
Faculty of Medicine, and we also work closely with the
Hospital for Sick Children.
The AVM Clinic is part of the Neurointerventional Radiology Program and
Neurosurgical Program at the Krembil Brain Institute at Toronto Western Hospital. Both of these programs are internationally recognized for their expertise and research. Since the early 1980s, specialists at the Krembil Brain Institute have pioneered image-guided technologies and developed surgical techniques that have revolutionized the field.
A totally integrated imaging and treatment environment is equipped with the most sophisticated 3-D angiography system, high-powered MRIs and now Gamma Knife radiosurgery. Here, neurointerventional specialists and surgeons diagnose and treat some of the most complex neurovascular conditions including stroke, aneurysms and AVMs.
You will be contacted with information about your first appointment.
Please bring the following to your appointment. Not all of these items may be needed for your appointment. Our clinic or your referring doctor will let you know what you must bring.
Please arrive 15 minutes before your appointment.
When you arrive, you will sign in with the receptionist. You will need your health card (OHIP card) to sign-in. If you do not have an OHIP card, please bring another form of government-issued photo ID, such as a driver’s license or passport.
You may be given a Measuring Health Equity Questionnaire to fill out. This form contains questions about your background. We collect this information to find out who we serve and what unique needs you may have. The form is voluntary and you can choose ‘prefer not to answer’ to any or all questions. However, the information you choose to give us will help us improve the quality of care for you and others.
First appointments take longer than follow-up appointments. Your first appointment can take 2 hours or more. Follow-up appointments usually take 15 to 30 minutes. We do everything we can to stay on time but sometimes unforeseen circumstances may delay your appointment.
At the end of your first appointment, the nurse or doctor will give you a contact list for your health care team. If you don’t get a contact list, feel free to ask for it.
After every appointment, a member of your health care team will tell you about your next visit. Be sure you understand what is going to happen next. For example, know the time and place of your next visit or if someone will call you with this information.
If you are unsure about what your next steps are, don’t be afraid to ask a member of your team. We are here to help you.
We understand that reaching us by phone can sometimes be difficult. Often our phone lines are busy or are turned over to the message centre so our staff can prepare for clinic visits or help other patients. We make every effort to return your call within 24 hours. Our staff will try to reach you 2 times. If we are not able to reach you directly you may need to call us again.