Dural arteriovenous fistula (DAVF)

Conditions & TreatmentsBrain Vascular MalformationDural arteriovenous fistula (DAVF)

Dural arteriovenous fistula (DAVF) is a rare vascular condition where abnormal connections (fistulas) are made between branches of arteries and veins in the brain covering (dura mater).

The dural arteries bring high pressure oxygen-rich blood to the brain and the dural veins take the oxygen-depleted (deoxygenated) low pressure blood back to the heart. A DAVF causes the high-pressure arterial blood to enter into the veins or sinuses that normally handle low-pressure blood returning to the heart. This can result in ruptures leading to bleeding and brain hemorrhage as well as other neurological issues.

Dural arteriovenous fistula (DAVF)

Schematic overview of the Borden system of classification for DAVFs. A, Type 1 fistula with multiple communications between the occipital artery and transverse sinus. Note antegrade flow and no cortical venous reflux. B, Type 2 lesions are associated with cortical venous reflux. This illustration demonstrates the presence of a transverse sinus fistula with stenosis of the distal transverse and proximal sigmoid sinuses. There is retrograde blood flow into the proximal transverse sinus and the cortical vein (please also see Fig 1E, -F). C, Type 3 fistulas represent communication between the meningeal arteries and cortical vein (or an isolated segment of venous sinus). In this schematic drawing, the cortical vein harboring the fistula near the frontal convexity is tortuous and has multifocal stenoses in its pathway, 2011 Lydia Gregg. Source: ajnr.org

 

Symptoms: Patients with DAVFs may be completely asymptomatic. Symptoms, when present, may range from mild symptoms to severe hemorrhage. The symptoms depend on the location and drainage pattern of the DAVF. Neurological symptoms include:

  • Bruit (sound heard due to unusual blood flow)
  • Headache
  • Pulsatile tinnitus (ringing in the ears)
  • Visual difficulty
  • Seizures

Diagnosis: Diagnosis is typically made by imaging using CT, CT angiography (CTA), MRI, or angiography. In general, DAVFs appear in both men and women in their 50’s to 60’s with hemorrhage due to DAVF being more common in men. It is unclear why DAVFs develop although there is a correlation with trauma, surgery, tumors and infection.

Treatment: First line treatment options include the use of endovascular surgical techniques and depends on the drainage pattern of the DAVF and the patient’s symptoms. Endovascular embolization is a minimally invasive procedure commonly used to treat dural arteriovenous fistulas. A catheter is threaded through an artery in the groin up to the DAVF and the fistula is sealed off using glue, a metal coil, or a balloon thus stabilizing the blood flow.

In some cases, stent placement using a microsurgical approach may be used in combination with embolization.