What is an arteriovenous malformation?
An arteriovenous malformation (AVM) is a tangled mass of blood vessels with abnormal connections between arteries and veins. These abnormal connections result in high pressure arterial blood being pumped directly into weaker walled veins. The veins often cannot withstand the high pressure and may break, causing bleeding directly into the brain. AVMs can also interrupt the blood supply to specific parts of the brain by drawing blood flow away from other areas and into itself.
What causes an arteriovenous malformation?
Arteriovenous malformations are primarily congenital, meaning they develop while the fetus is forming in the womb and individuals are born with them. The cause of AVM development in utero is not fully understood. Most AVMs are not inherited, though certain hereditary conditions that affect blood vessel formation can increase a person’s risk. AVMS are slightly more common in males.
How is an arteriovenous malformation treated?
Left untreated, the most serious complication of an AVM is rupture and bleeding into the brain, which can cause significant permanent neurological damage and even death. The three main treatment options are as follows and can be utilized alone or in combination: surgery, embolization, and radiation.
- Surgical Resection: A neurosurgeon performs a craniotomy to access the brain and reach the AVM. Then the surgeon removes as much of the abnormal blood vessel tangle as possible in order to optimize blood flow in the affected area and prevent AVM rupture and bleeding into the brain.
- Endovascular Embolization: A special catheter is threaded through an artery to the AVM. Then tiny metal coils or a glue like substance is injected through the catheter to reduce or block blood flow in the AVM. Embolization of the AVM reduces risk of hemorrhage and redirects blood flow to normal brain tissue.
- Radiotherapy: Often referred to as radiosurgery or “Gamma Knife”, precisely focused beams of radiation are targeted at the AVM to destroy it. The radiation damages the blood vessels resulting in scarring which leads to clotting off of the vessels over time.