Dural Arteriovenous Fistula (DAVF)
What is a dural arteriovenous fistula (DAVF)?
A dural arteriovenous fistula (DAVF) is a vascular anomaly formed by an abnormal connection between an artery within the tough covering of the brain (dura mater) and a vein that carries blood from the brain back to the heart.
A DAVF can transfer high-pressure arterial blood into veins or venous sinuses that normally carry low-pressure, deoxygenated blood returning to the heart from the brain. This can cause neurological symptoms and bleeding into the brain (brain hemorrhage, or hemorrhagic stroke).
Dural Arteriovenous Fistula (DAVF) Symptoms
Although dural arteriovenous fistulas are located outside the brain, they can cause a wide range of neurological symptoms. Symptoms largely depend on the drainage pattern.
Symptoms may include:
- Bruit (abnormal sound associated with turbulent blood flow)
- Tinnitus (ringing in the ears)
- Visual impairment
- Papilledema (swelling of the optic disc indicative of intracranial pressure)
- Cognitive impairment
Dural Arteriovenous Fistula (DAVF) Treatments
Treatment depends on the drainage pattern of the dural arteriovenous fistula and your symptoms.
Most DAVFs can be cured with endovascular embolization, a minimally invasive procedure in which a catheter is threaded through the arteries and veins of either your wrist or leg to the site of the fistula. The fistula is then plugged with a material such as glue, a metal coil, or a balloon to correct the abnormal pattern of blood flow.
For some DAVFs, microsurgery may be recommended instead of or in addition to endovascular embolization, though these cases are rare.
How common are dural arteriovenous fistulas?
Dural arteriovenous fistulas are rare.
Who gets dural arteriovenous fistulas?
Symptoms of dural arteriovenous fistulas present at an average age of 50 to 60 years old, but people have been diagnosed at various ages. These abnormalities affect both men and women, but hemorrhages from DAVFs occur more often in men.
These vascular anomalies are usually acquired, meaning they are not present from birth. In most cases, the cause is not obvious. However, DAVFs can be associated with trauma, surgery, tumors, or infection.
How are dural arteriovenous fistulas diagnosed?
The following tests may be used to diagnose a dural arteriovenous fistula:
- MRI scan
- CT scan
- Cerebral angiography
Of these studies, cerebral angiography is the gold standard. While both CT and MRI scans may demonstrate features suggestive of a DAVF, CT and MRI can sometimes miss DAVFs. Cerebral angiography definitively identifies the existence of a DAVF and should be performed if a DAVF is suspected.
Are dural arteriovenous fistulas life threatening?
Yes, DAVFs can be life-threatening if they demonstrate high-risk features such as increased venous pressure and narrowing of the associated dural sinuses.
Can a dural arteriovenous fistula be cured?
Yes, the most common means of treating—and curing—a DAVF is through endovascular embolization. Open brain surgery rarely is required to treat a DAVF.
What causes dural arteriovenous fistula?
The majority of DAVF have no known cause. However, certain conditions such as infection, cranial trauma, tumors, and prior surgery may make it more likely that you will develop a DAVF. Some hereditary vascular diseases are also associated with a higher rate of DAVF.
What is high-risk dural arteriovenous fistula?
These are DAVF that are associated with increased venous pressure or narrowing of the veins on the covering of the brain. Veins under increased pressure can rupture causing intracerebral hemorrhage.