Arteriovenous fistulas (AVFs)

The Cerebrovascular Surgery and Interventions Center treats arteriovenous fistulas and other cerebrovascular conditions. Arteriovenous fistulas (AVFs) are rare abnormalities in which arteries connect directly with veins, bypassing the capillaries. They can occur anywhere in the body.

Brain AVFs are most often found in the dura mater, the protective membrane lining the brain and spinal cord, also called the meninges. These are referred to as dural AVFs (dAVFs). Another, rarer type of AVF involves vessels on the surface of the brain itself; these are known as pial AVFs (pAVFs).

Depending on their location and which blood vessels are involved, AVFs may need to be treated urgently, depending on the risk they pose.

Anatomy of an AVF

AVFs place a strain on the blood vessels. Normally, the arteries that carry high-pressure, fast-flowing blood branch into smaller and smaller vessels, ending in capillaries, where blood flow slows down and the tissues get oxygen. The veins then carry low-pressure, slow-flowing blood from the capillaries back to the heart.

But in AVFs, veins in the brain or spinal cord receive high-pressure blood directly from the arteries, bypassing the capillaries. The extra strain on these veins can cause them to bleed, a potentially life-threatening or permanently disabling event. Even if there is no bleeding, chronically elevated pressure in these veins can eventually damage brain or spinal tissue, leading to progressive neurological dysfunction.

How we care for AVF at Boston Children’s Hospital

Our goal is always to close off the AVF before the abnormal blood flow can damage the brain or spinal cord. The Cerebrovascular Surgery and Interventions Center team will recommend the best technique or combination of techniques for each child, based on the type of AVF and its location, and guided by detailed imaging studies. In our experience, most children have an excellent prognosis.