Arteriovenous malformations (AVMs) are abnormal tangles of arteries and veins that belong to a group of disorders known as vascular malformations. Although not completely understood, they typically develop in the womb or soon after birth and may be linked to genetic mutations. When AVMs are located in the brain or spinal cord, they're called neurological AVMs.
Although people are born with AVMs, symptoms may not develop until adulthood, often between 20 to 40 years of age, after the condition progresses, and in most adults, they cause no health problems. About 1 percent of those affected, however, experience life-threatening complications.
Serious complications occur when AVMs:
The most severe risk is bleeding, called a hemorrhage, in the brain, which can lead to a debilitating or fatal stroke.
At UCSF Medical Center, our Neurovascular Disease and Stroke Center is one of the world's leaders in diagnosing and treating AVMs. We treat more than 100 AVM patients a year. Our team includes neurologists, neurosurgeons and neuroradiologists who offer a wide range of treatments, including an advanced endovascular techniques, called embolization, which is an alternative to surgery.
Most people with arteriovenous malformations don't experience any symptoms. For those that do have symptoms, the most common include:
Symptoms can vary widely, depending on the location of the AVM. Other symptoms are memory loss, muscle weakness, and visual distrubances, such as partial vision. Some researchers believe the condition can cause subtle learning or behavioral disorders, long before other symptoms emerge.
The most serious complication is bleeding in the brain, resulting in a stroke.
Damage from AVMs tend to build-up over time. In women, pregnancy can sometimes trigger symptoms due to increases in blood volume and blood pressure.
The following tests may be used to diagnose your arteriovenous malformation (AVM), as well as help identify its size, location and blood-flow pattern.
Angiography — This special X-ray exam shows the structure of a person's blood vessels and is essential in the diagnosis and treatment planning of AVMs. During this procedure, a harmless dye that can be seen on X-rays is injected into an artery that supplies blood to the brain. The dye follows the path of the brain's blood flow and can show any obstructions or leaks.
Computed Tomography (CT) Scan — With this test, X-ray beams are used to create a 3-dimensional image of the brain. A CT scan typically can detect bleeding into the brain, called a hemorrhage, which indicates an AVM.
Magnetic Resonance Angiography (MRA) — This procedure is a magnetic resonance imaging (MRI) study of the blood vessels and provides detailed images of blood vessels. Using a strong magnetic field, an MRI generates a 3-D image of the brain to detect, diagnose and aid the treatment of vascular disorders. The procedure is painless.
Today, there are many safe and highly effective therapies available to treat arteriovenous malformations (AVM). These include surgery, radiation therapy, embolization and radiosurgery using a device called a Gamma Knife.
Conventional Surgery — In many cases, surgery may be recommended to completely remove the AVM. This is appropriate when the AVM is small and located on the surface of the brain or spinal cord. When the AVM is deep in the brain, other minimally invasive techniques are used to prevent damage to surrounding tissue.
Embolization — Embolization is a technique used to reduce blood flow to the AVM by obstructing surrounding blood vessels. During this procedure, the AVM is filled with specially designed coils, glues or spheres that plug its vessels and decrease the flow of blood. Embolization usually doesn't permanently resolve the AVM but makes it more manageable for future procedures such as surgery.
Reviewed by health care specialists at UCSF Medical Center.