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Arteriovenous Malformation (AVM)

What Is Arteriovenous Malformation (AVM)?

An arteriovenous malformation (AVM) is an abnormal connection between arteries and veins, resulting in a “tangle” of blood vessels in the brain and spinal canal. In normal circulation, blood flows from arteries to capillaries and then to veins, taking blood from high pressure to low pressure gradually. However, in AVMs, blood flows directly from arteries to veins through an abnormal passageway called a fistula, rather than through capillaries. This leads to downstream effects, including increased flow and pressure. Over time, the vessels fatigue, leading to rupture. The injury can endanger physical and neurological functions — such as sight, sensation, critical thinking and movement — that are associated with that area of the brain. A rupture also can be fatal.

Some brain AVMs come to attention in ways other than bleeding, such as seizure. The majority of patients are between 20 to 50 years of age when a brain AVM comes to be diagnosed. However, brain AVMs can affect people of any age.

Nirav J. Patel, MD, Neurosurgeon at Brigham and Women’s Hospital, discusses the treatment and approach to care for an Arteriovenous Malformation (AVM) diagnosis.

What Are the Risk Factors for Arteriovenous Malformation (AVM)?

This tangle of arteries and veins usually develops before birth or shortly after. Occasionally, an AVM forms later in life, though it is unclear if the risk for an AVM is passed down through families genetically. For someone with an AVM, an increase in blood pressure is a risk factor for rupture.

What Are the Symptoms of an AVM and How Is It Diagnosed?

Most people who have an AVM may be unaware of the abnormality and experience no symptoms. Some brain AVMs present with symptoms including:

  • Seizures, new onset
  • Muscle weakness or paralysis
  • Loss of coordination
  • Difficulties carrying out organizational tasks
  • Dizziness
  • Headaches
  • Visual Disturbances
  • Language Problems
  • Abnormal sensations (numbness, tingling or spontaneous pain)
  • Memory deficits
  • Mental confusion
  • Hallucinations
  • Dementia

Women with AVMs can sometimes develop symptoms during pregnancy.

  • Computed Tomography Angiography (CTA) uses a series of x-rays to create a cross-sectional image of the brain. To better visualize an AVM, contrast dye is injected while the CT scanner takes pictures. This enables radiologists to map the AVM in greater detail and produce a 3D composite image of the AVM.
  • Magnetic Resonance Angiography (MRA) is a type of MRI scan that uses a powerful magnet to create highly detailed images of your brain without using x-ray radiation.
  • Digital Subtraction Angiography (DSA), also called Cerebral or Spinal Angiography depending on the region being imaged, is the most comprehensive procedure offered by our neuroradiology team to help characterize an AVM. In this exam, an endovascular neurosurgeon inserts a catheter into an artery near the groin and guides it to the head/neck or spine region. Using contrast dye and fluoroscopy (a type of x-ray) images are taken of the dye traveling through arteries and veins in the brain or spine. This provides an extremely detailed 3D map of the AVM, highlighting its location and characteristics. Knowing how blood flows within the AVM is very important to decision-making and planning.

What Are the Treatment Options for Arteriovenous Malformation (AVM)?

A team of specialists at Brigham and Women’s Hospital Center for Cerebrovascular Diseases (including neurosurgeons, endovascular surgeons, neurologists and radiation oncologists) collaborate to determine the best treatment for each AVM. The best treatment depends on the AVM’s location and anatomy and the decision is centered around the patient, to achieve a cure with the least risk.

  • Embolization involves injecting a material into the blood vessels that blocks blood flow to the AVM
  • Surgery can then be used to remove the AVM
  • Some AVMs are best treated with radiosurgery, which directs highly focused beams at the AVM. It can take time for the AVM to completely disappear after radiosurgery

Learn more about arteriovenous malformation treatment at Brigham and Women's Hospital.

Specialists in Treating Arteriovenous Malformations

The neurosurgeons at the Brigham and Women's Hospital Center for Cerebrovascular Diseases are skilled in advanced techniques for the repair of AVMs.

Our experienced neurosurgeons, vascular neurologists, and radiologists collaborate closely to determine the best course of treatment—including minimally invasive surgery—for each AVM patient. By applying advanced techniques and delivering comprehensive care, we can bring life-changing results to our patients.

As a patient at Brigham and Women's, you can count on:

  • Top-rated physicians and their teams to provide clear communication and the necessary support at every step of AVM treatment
  • Extensive experience in minimally invasive techniques performed by our endovascular neurosurgeons to prevent blood flow to the AVM
  • Clinicians who regularly participate in cerebrovascular research and clinical trials, ensuring they keep up with the latest innovations in the field

AVM in the News

Additional Resources

  • Make an appointment or request a referral by contacting us
  • View the Department of Neurosurgery locations
  • Explore resources for patients and families
  • Browse answers to neurosurgical patients’ frequently asked questions
  • Go to our online health library to learn more about brain tumors
  • Visit the Kessler Health Education Library in the Bretholtz Center on the main Brigham and Women’s Hospital campus, where patients and families can access computers, printed information and guides, and a knowledgeable staff


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