What is AVM?
The capillary bed is where the blood exchanges oxygen and nutrients with the body tissues. In an arteriovenous malformation (AVM), arteries connect directly to veins without a capillary bed in between. Veins are not able to handle the pressure of the blood coming directly from the arteries. The veins stretch and enlarge as they try to accept the extra blood. The weakened blood vessels can rupture and bleed. The cause of AVMs is unknown. AVMs of the brain are present at birth, but are usually not hereditary.
Most AVMs do not show symptoms until a bleed occurs. Common symptoms for AVMs found in the brain include:
- bleeding in the skull
- memory lapses
In general, an AVM may be considered for treatment if it has bled which can lead to stroke or death. Different types of treatment include:
- Medical therapy. If an AVM is in an area of the brain that can’t be easily treated, conservative medical management may be indicated. If possible, a person with an AVM should avoid any activities that may excessively elevate blood pressure.
- Surgery. If an AVM has bled and/or is in an area that can be easily operated upon, then surgical removal may be recommended. The patient is put to sleep with anesthesia, a portion of the skull is removed, and the AVM is surgically removed.
- Stereotactic radiosurgery. An AVM that’s not too large, but is in an area that’s difficult to reach by regular surgery, may be treated with stereotactic radiosurgery. In this procedure, a cerebral angiogram is done to localize the AVM. Focused-beam high energy sources are then concentrated on the brain AVM to produce direct damage to the vessels and allow the AVM to “clot off.”
- Endovascular neurosurgery. Embolization is a procedure that uses small catheters inserted into your blood vessels to deliver glue or other obstructive materials into the AVM so that blood no longer flows through the malformation. Catheter is inserted into an artery then passed through the blood vessels to the feeding arteries of the AVM.