Arteriovenous Malformation (AVM)

Arteriovenous malformations (AVMs) are abnormal tangles of blood vessels within the brain — specifically, they are abnormal arteries connected to abnormal veins. The abnormality is present from birth and found in 1 in 700 people (0.14% of the general population). Almost all AVMs are non-hereditary.

Washington University cerebrovascular surgeons work as part of a multidisciplinary team to offer treatment for arteriovenous malformations (AVMs) at the Barnes-Jewish Hospital Stroke and Cerebrovascular Center.

The Center is among the most experienced in managing brain vascular malformations and receives physician referrals from across the country. Along with cerebrovascular surgeons, other physician members of the treatment team include neurologists who specialize in interventional radiology, critical care and neuro-rehabilitation neurologists, and radiation oncologists, who perform Gamma Knife® Radiosurgery. AVMs are not cancerous, but radiation oncologists operate the Gamma Knife, a radiation tool that can be used to treat them.


People who have an AVM often have no symptoms at all and are diagnosed by chance when they visit a doctor about a different concern. When AVMs cause physical problems, patients are likely to experience one or more of these main  symptoms:

Seizure: While AVMs can cause seizures, not all result in the type of seizure in which the body shakes rapidly and uncontrollably. There are many types of seizures. Some have mild symptoms, last from 30 seconds to two minutes and do not cause lasting harm. Others last longer or can occur one after the other.

Headache: Although many patients with AVMs have headaches, the vast majority of the pain proves to be unrelated to the AVM. Yet the AVM itself can cause headaches in a small number of patients, and these can fade when the AVM is treated.

Stroke-like effects: In some patients, blood flow is diverted away from part of the brain to the AVM, which can lead to symptoms similar to those caused by a stroke. A patient may suffer weakness or numbness on one side of the body, difficulty speaking or understanding speech, loss of vision, double vision and balance difficulties.

Brain hemorrhage: AVMs can rupture and cause bleeding in the brain (also called a hemorrhagic stroke). Symptoms that suggest brain hemorrhage include sudden onset of a severe headache; nausea, vomiting, weakness or numbness on one side of the body; difficulty speaking or understanding speech; loss of vision; double vision and balance difficulties. People experiencing any of these symptoms should call 9-1-1. Brain hemorrhage is a form of stroke that can cause serious brain injury and even death, although many patients make good long-term recoveries.


AVMs, which can cause hemorrhagic stroke, are treated on a case-by-case basis. The treatment selected depends on the location and size of the AVM, the severity and nature of symptoms, the patient’s age and health status, and the risk involved in treatment. 

Treatment options include:

  • Observation
  • Surgery
  • Gamma Knife radiosurgery
  • Endovascular embolization

Observation: This may be an appropriate approach for certain patients, including people who are older, have multiple medical problems or have complex AVMs for which treatment carries high risk.

Surgery: In this inpatient procedure, the AVM is removed from the brain through open surgery. If successful, it provides immediate protection against AVM rupture. Surgery is a good option for many AVM patients. If the AVM is complex or difficult to reach, however, this treatment may be a less attractive option.


Gamma Knife Radiosurgery: This less-invasive form of treatment is a one-day outpatient procedure in which beams of radiation are precisely focused on the AVM, causing it to shrink over time. In most patients, the AVM will be cured in 1-3 years after treatment. Such radiosurgery is most useful for smaller AVMs, but can be used selectively for the treatment of larger AVMs.

Cavernous Malformation

Endovascular Embolization: A small catheter (tube) is used in this inpatient procedure. The catheter is passed from a blood vessel in the groin (or arm) up into the AVM, where glue or other material is injected. Endovascular embolization is primarily used in preparation for surgery or radiosurgery to make the treatments safer and more effective. In some cases, the treatment can cure the AVM, making surgery or radiosurgery unnecessary.