What Is a Dural Arteriovenous Fistula?

A dural arteriovenous fistula, or DAVF, is a condition with abnormal channels between arteries and veins in the dural region that covers the brain and spinal cord. It is a result of blood clots or traumatic head injuries.

Dural arteriovenous fistulas are most common in people over 55 years of age, but they also appear in children and young adults.

Although the cause is unknown in most dural arteriovenous fistulas, there are a number of potential risks that may contribute to their appearance, such as:

• Blood coagulation disorders, which can cause venous sinus occlusion.
• Prior brain surgery.
• Infections.
• Traumatic head injuries.
• Presence of benign meningeal tumors.
• Deep vein thrombosis.

In a dural arteriovenous fistula, one of the most common signs is pulsatile tinnitus, which is a rhythmic ringing sensation in the ear that coincides with the heartbeat. It is caused by turbulent blood flow.

Persistent headaches, dizziness, blurred vision, or diplopia (double vision) may also occur, and in advanced cases, there may be weakness or numbness of the limbs.

In severe cases, when the retrograde venous drainage affects the brain, focal neurological symptoms such as seizures, difficulty speaking, memory impairment, or loss of coordination may appear.

If there is intracranial bleeding, which can be of sudden onset, an intense headache and a decreased state of consciousness are present.

Generally, the progression of symptoms is gradual, but in certain variations, the evolution is rapid and can be fatal if not treated properly.

Diagnosis of a Dural Arteriovenous Fistula

The diagnosis of a dural arteriovenous fistula begins with clinical suspicion, especially in patients who have pulsatile tinnitus and atypical neurological symptoms.

MRI and magnetic resonance angiography are then used to detect abnormalities in blood flow and changes in the brain parenchyma (the functional substance of the brain) associated with abnormal venous drainage.

A CT scan may also be used to identify intracranial hemorrhages related to the dural arteriovenous fistula.

The confirmatory diagnosis is made by digital subtraction cerebral angiography, which is considered the gold standard. This study provides a detailed visualization of the supplying arteries and the exact location of the fistula, as well as the venous drainage pattern. All of this is essential information for planning treatment.

Sometimes, the Cognard or Borden classification is used to estimate the risk of complications, which helps guide the therapeutic strategy.

Dural Arteriovenous Fistula Treatments

The treatment for a dural arteriovenous fistula aims to close the abnormal connection and prevent bleeding or neurological damage complications.

Endovascular embolization is the most frequently used option. A microcatheter is introduced into the fistula to occlude it with adhesives, coils, or particles. This minimally invasive procedure can be performed via a venous or arterial route, depending on the anatomy of each case.

For situations where embolization is not possible or not completely effective, surgery is used to remove or isolate the fistula, or stereotactic radiosurgery, which uses focal radiation to gradually close the abnormal vessel.

The choice of treatment will vary depending on the location of the fistula, the patient’s general condition, and the clinical urgency.

Close monitoring is crucial because a dural arteriovenous fistula can recanalize and require new treatment.

At the Vascular, Arterial, and Venous Disease area of Centro Médico ABC, we can provide you with specialized care. Contact us!