Arteriovenous fistulas form when veins and arteries create abnormal connections. Normally, those systems are separated – the arteries move blood from the heart to the tissues and the veins move it back from the tissues to the heart. In the case of arteriovenous fistulas, the direct connection results in high-pressure arterial blood flowing directly through veins. This can cause a buildup of pressure or blood clots in the veins surrounding the brain or spinal cord, resulting in nervous system dysfunction, seizure and hemorrhage.
AVFs are similar to arteriovenous malformations (AVM) in that both have abnormal connections between arteries and veins. But unlike AVMs, which develop in the tissue of the brain or spinal cord, AVFs are most commonly found in the covering of the brain or spinal cord. Most are found in the dura mater, the outermost membrane surrounding the brain and spinal cord. These are called dural arteriovenous fistulas (DAVF). Carotid-cavernous arterial fistulas (CCF) are also common. These involve branches of the carotid arteries and the cavernous sinus.
The most common symptom of either DAVF or CCF is called a bruit. A bruit is a whooshing sound in the fistula caused by the high-pressure blood flow. People with an arteriovenous fistula will often hear a heartbeat-like sound in their ears. Those with CCF may also experience swelling or redness in one or both eyes and double vision.
At UCLA, we use the most advanced technology and latest imaging systems to diagnose AVFs quickly and accurately. In many cases, an AVF is discovered once the abnormal blood flow has put enough pressure on the brain to cause symptoms, but whenever possible we try to locate and treat them sooner. During your examination, your expert team may use the following imaging techniques to locate and assess your AVF:
After your diagnosis, a multidisciplinary team of neurovascular experts will meet to review your case and create a customized treatment plan. At UCLA, we typically treat AVFs using strategies that include some combination of: