Health Topic

Arteriovenous Malformations

Arteriovenous malformations (AVMs) are defects in your arteries, veins, and capillaries. They are common in the brain and spine. Find out more.

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Also called: AVM

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Arteriovenous Malformations

Arteriovenous malformations (AVMs) are defects in your vascular system. Your vascular system is your body's network of blood vessels. It includes your:

  • Arteries, which carry oxygen-rich blood from your heart to your tissues and organs.
  • Veins, which carry the blood and waste products back to your heart.
  • Capillaries, which are tiny blood vessels that connect your small arteries to your small veins.

An AVM is an abnormal tangle of arteries and veins. They are connected to each other, with no capillaries between them. Without the capillaries, the blood flow from the arteries goes directly into the veins at a faster rate than normal. Because of this, the nearby tissue does not get all the oxygen it would normally get. This lack of oxygen can lead to tissue damage and the death of nerve cells and other cells. The fast rate of blood flow can also increase the blood pressure inside the arteries and veins. This can weaken the arteries and veins. A weakened artery or blood vessel could burst or leak blood.

AVMs are rare. The cause of AVMs is unknown. Most of the time, people are born with them. But sometimes they can appear shortly after birth or later in life.

The symptoms of AVM will depend on where the AVM is located. They can happen anywhere in the body, but they are more common in the brain or spinal cord. Most people with brain or spinal cord AVMs have few, if any, major symptoms. But if a weakened blood vessel bursts, it can spill blood into the brain (called a hemorrhage). Severe hemorrhages can cause a stroke and brain damage.

If an AVM is causing symptoms, they can include:

  • Seizures
  • Headache
  • Pain in the area where the AVM is located
  • Vision problems
  • Muscle weakness
  • Problems with movement and speech
  • Confusion
  • Dizziness
  • Loss of consciousness

To find out if you have an AVM, your health care provider:

  • Will ask about your symptoms and medical history.
  • Will do a physical exam. This may include listening for a bruit. A bruit is whooshing sound caused by the rapid blood flow through the arteries and veins of an AVM.
  • May order imaging tests, such as a CT scan, MRI, ultrasound, or cerebral angiography. For a cerebral angiography, you are injected with a special dye that helps the blood vessels in your brain show up on x-rays.

Treatments for AVMs will depend on factors such as:

  • Where the AVM is located
  • Its size
  • Your symptoms
  • Your overall health
  • Your risk of bleeding

The treatment options may include:

  • Monitoring for any signs that may mean you have an increased risk of hemorrhage.
  • Medicines to help with the symptoms from AVMs.
  • Surgery, which may be done if you have a higher-than-usual risk of bleeding. There are a few different types of surgery for AVMs. In some cases, you may have more than one type. Surgery can be risky, especially when it's done on the brain or spinal cord. So you and your provider will need to discuss the risks and benefits of doing the surgery before you make a decision.

It sits within Blood, Heart and Circulation and Brain and Nerves.

The lead U.S. institute for this subject is the National Institute of Neurological Disorders and Stroke.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Arteriovenous Malformations

376 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Diagnosis and Tests

Treatments and Therapies

Genetics

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Arteriovenous Malformations. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Arteriovenous Malformations, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.