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 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.
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.
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.