Arteriovenous Malformation Treatment

Arteriovenous Malformation
An arteriovenous malformation (AVM) is an abnormal collection or tangle of blood vessels. The malformations, which usually are genetic in origin, restrict or alter blood flow and are associated most commonly with bleeding, strokes and seizures.

In general, arteries carry supply oxygen-rich blood to the body's tissues and veins move oxygen-depleted blood back to the heart and lungs. In some AVMs, the capillaries, the tiny vessels that are between the arteries and the veins and allow oxygen and nutrients to reach body's tissues, are absent.  Hence, the arteries connect directly to the veins.  This is called a fistula.

AVMs can occur anywhere in the body, however, BRAIN AVMs are of special concern because of the damage they cause when they bleed. They are very rare and occur in less than 1% of the general population.

AVMs are very complex lesions.  Treatment often involves a combination of embolization, surgery and radiation.  Typically, an angiogram must first be performed to obtain a definitive diagnosis.  Interventional Radiologists perform embolization usually as a first step in treatment.  Embolization involves blocking some or all of the arteries which supply the blood to an AVM.
 

Where do AVMs occur?
They can occur in any organ in the body, in order of frequency: head, limbs, trunk, and internal organs.

What do AVMs look like?
In infancy and childhood, the blush of an AVM can be mistaken for hemangioma (the most common tumor of infancy). AVMs become obvious as signs of fast blood flow appear. The skin becomes a darker red or purple color, nearby veins enlarge and there is local warmth.

How are AVMs treated?
It may be possible to treat part or all of the AVM by placing a catheter (small tube) inside the blood vessels that supply the AVM and blocking off the abnormal blood vessels with a variety of different materials. These include liquid tissue adhesives (glues), micro- coils, particles and other materials used to stop blood flowing to the AVM. This procedure is called Endovascular Embolization.

BRAIN AVMs
What is a brain AVM?
An arteriovenous malformation (AVM) is an abnormal collection of blood vessels occurring within the brain itself. 

What factors influence whether an AVM should be treated?
In general, an AVM may be considered for treatment if it has bled, if it is in an area of the brain that can be easily treated and if it is not too large.

How are brain AVMs treated?
It may be possible to treat part or all of the AVM by placing a catheter (small tube) inside the blood vessels that supply the AVM and blocking off the abnormal blood vessels with a variety of different materials. These include liquid tissue adhesives (glues), micro- coils, particles and other materials used to stop blood flowing to the AVM. This procedure is called Endovascular Embolization. Embolization is performed under general anesthesia.  A catheter is directed through the femoral artery, usually in the right groin, to the blood vessels in the neck and a diagnostic angiogram is obtained. Using this information and live fluoroscopic visualization, a smaller microcatheter can be navigated into the arteries supplying the AVM.  Another angiogram is done to determine whether it is a safe artery to block off.  If so, then liquid embolic agent is used such as ONYX or N-butyl cyanoacrolate in a mixture with radio-opaque material.  This process is repeated up to several times after which the catheters are removed.  The patient is awakened from anesthesia and transferred to the Neurointensive care unit.  Patients are usually in the hospital for elective procedures for 1-2 days.  Blood flow to the AVM may be treated in stages to prevent thrombosis or hemorrhage from occurring.  In some cases, embolization may fully treat a lesion, but most patients will undergo surgical resection or radiation therapy

How do I prepare for the procedure?
You will be scheduled for a consultation with the Interventional Radiology Team. Bring a list of questions to ask your doctor. It is important that you understand exactly what procedure is planned, the risks, benefits and other options before your procedure.

What kind of follow up is needed?
Approximately two weeks after procedure you should schedule an office visit with the Interventional Radiology team.

If you have any questions or need to reschedule an appointment please feel free to contact the Interventional Radiology Office at 802- 847-8359. Our business hours are Monday – Friday 8:30 a.m. to 5 p.m. Someone is available to take your call after hours for emergencies.

This information is provided by the Fletcher Allen Health Care, Department of Radiology, Division of Interventional Radiology and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. For additional health information, please contact your health care provider.