Arteriovenous malformations (AVMs) are abnormal tangles of arteries and veins in the brain or spinal cord. Arteries carry oxygen-rich blood away from the heart to the body’s cells and veins return oxygen-depleted blood to the lungs and heart. When arteriovenous malformations disrupt this process, they can reduce the amount of oxygen received by brain tissues.

AVMs are typically caused by mistakes that occur during fetal development. Although not completely understood, these defects can form wherever there are arteries or veins in the brain or spinal cord and may be linked to genetic mutations.

AVMs affect about 300,000 North Americans, occurring equally in males and females from all ethnic and racial backgrounds.

Although people are born with AVMs, symptoms typically don’t develop until early adulthood, between 20 to 40 years of age. The majority of people with AVMs never experience any related problems. For those that do experience symptoms, the most common include:

• Hemorrhage or bleeding into the brain
• Headache
• Stroke
• Seizures
• Other neurological deficits, depending on the AVM location

AVMs can also be fatal.

Treatment is often directed towards symptoms. Other times it consists of surgery or radiation therapy. Cutting off the blood supply to the AVM with coils, particles, or glue (embolization), may also be used in addition to other treatments.