Congenital arteriovenous malformations (AVMs)

What are congenital arteriovenous malformations (AVMs)?

Arteriovenous Malformations (AVMs) are abnormal tangles of arteries and veins. They can occur anywhere in the body, but our team specifically manages and treats those that are present in the brain and spinal cord. These abnormalities are typically congenital and are present at birth.

They usually are not detected unless they cause seizures, weakness or have ruptured and bled in the brain. Neurologic or life threatening sequelae are associated with each hemorrhage. There is a 4% per year risk of hemorrhage once an AVM has become symptomatic. 

Treatment is required to reduce that risk and subsequent problems associated with additional hemorrhage. Treatment for AVMs can be quite complex and it is critical that patients with this disorder be managed and surgically treated in a center with extensive AVM experience.

The Center for Cerebrovascular Disorders in Children are among the very best in the region at performing the most advanced procedures and therapies for the treatment of pediatric cerebrovascular disease. Each of our primary team members works solely in the pediatric setting with a clinical interest in disorders of cerebrovascular system.

This program is the only one of its kind in Texas, and one of a handful across the nation. It offers a unique level of expertise in the management and treatment of patients with AVMs specific to children and adolescents. We are the only program in Dallas to offer pediatric neurosurgery and neuro-radiology coverage 24 hours a day by specialized, dedicated pediatric providers.

Please email ccdc@childrens.com to schedule an appointment.

What are the signs and symptoms of congenital arteriovenous malformations (AVMs)?

Symptoms depend on the severity and location of a cerebral AVM as well as if the AVM has ruptured.

Children may experience:

• Seizures

• Nausea and vomiting

• Persistent headaches

• Weakness on one side of the body or stroke-like symptoms

• Speech changes

• Numbness or tingling of the arms or legs

• Sudden loss of consciousness (with rupture)

How are congenital arteriovenous malformations (AVMs) diagnosed?

If your doctor suspects your child has an AVM, the doctor will do a complete exam of your child.

One or more of the following may be ordered:

• CT angiogram - This test uses X-rays to produce multiple images of the inside of the body. These three-dimensional pictures of the brain can be used to further evaluate conditions that affect blood vessels within the brain.

• MRI with magnetic resonance Angiography (MRA) - This procedure uses radiofrequency to create accurate two- and three-dimensional images of the arteries in the neck and brain.

• Cerebral angiogram - This test is performed by an interventional radiologist who specializes in the care of children. This is extremely important as children have smaller blood vessels, limitations on dye administration, and specific radiation recommendations.

• The cerebral angiogram is a minimally invasive procedure which uses a special contrast, or dye, to observe blood flow in the brain. During the procedure, the radiologist places a small IV or catheter in a blood vessel in the groin, which they then uses to reach the blood vessels that supply the brain. With the help of the special contrast or dye, an X-ray machine moves in different angles and takes pictures of the blood vessels.

• A team consisting of a radiologist, anesthesiologist, radiology technologists, and nurses will care for your child throughout the procedure.

• Following the procedure, your child will have to lie flat for approximately four hours due to puncture of a large blood vessel in the groin, as this decreases the risk of bleeding. If needed, your child will receive medication to help them relax and rest during this time.

• This can be an outpatient procedure; however, if treatment is performed, such as embolization, your child will be admitted for observation by our team.

What are the causes of congenital arteriovenous malformations (AVMs)?

Arteriovenous malformations (AVMs) are a rare, congenital (present at birth) condition.

How are congenital arteriovenous malformations (AVMs) treated?

Treatment varies based on the size,  location, symptoms, and severity of the malformation. Our team offers a comprehensive approach with a multitude of possible treatment interventions or combination of treatments that include, but are not limited to medical management, interventional radiographic techniques, such as embolization, open microsurgical resection, or radiosurgery.

• Embolization is performed  in conjunction with a conventional cerebral angiogram. It is often considered an adjunct to open microsurgery in an attempt to reduce the risk of open surgery. Occasionally it will be utilized in the acute or early phase of treatment if there is an associated aneurysm with the AVM. 

  • During this procedure, a specialized interventional neuro-radiologist or neurosurgeon inserts a thin plastic catheter into an artery in your child’s groin. The catheter is guided into the AVM and a special material is injected that shuts off the artery and reduces the flow of blood to the vascular abnormality.

• Neurosurgery or open microsurgery - Surgical intervention for cerebrovascular disorders requires a highly specialized and meticulous approach. This approach requires a craniotomy, removal of a piece of the skull followed by its replacement and following which our neurosurgeon utilizes a microscope to better visualize the small blood vessels that supply the brain to remove the malformation. 

  • This procedure requires an inpatient hospitalization the length of which is determined by the extent of surgery. Often, a conventional angiogram upon its completion is utilized to confirm the treatment has been effective.

• Radiosurgery - We offer a unique treatment for arteriovenous malformations with radiosurgery. Radiosurgery is a unique form of radiation delivered to the brain in a very focused location allowing the treatment of a specific abnormality while avoiding injury to normal brain tissue. 

We utilize two forms of radiosurgery depending on the specific characteristics of the AVM.

• Gamma knife radiosurgery 

• CyberKnife LINNAC radiosurgery

These procedures are considered  minimally invasive and are performed as a day procedure. They use high doses of radiation to target and treat the abnormal blood vessels of the AVM. Over time, radiation causes the blood vessels to thicken and eventually constrict to the point that they occlude such that the AVM eventually obliterates.

After the treatment, it takes up to two to three years for the AVM to essentially dissolve. The procedure is typically reserved for patients with AVMs in areas of the brain that are difficult to reach through surgery, patients who have medical conditions that further complicate surgery, or families that do not want an open operation. However, not all children with an AVM will be a candidate for this procedure.