Dural Arteriovenous Fistula (DAVF) Symptoms & Treatment
An arteriovenous fistula (AVF) is an abnormal connection between an artery and a vein (AVF). AVFs can be present at birth (congenital), develop after birth or arise as a result of an injury (acquire). AVF’s can happen anywhere in the body, although we are mostly found in the head, neck, spine, and liver.
Dural arteriovenous fistula (Dural AVF) is a rare vascular condition where abnormal connections (fistulas) are made between branches of arteries and veins in the brain covering (dura mater). Dura-mater is one of the layers between the brain and the skull. These layers, which behave like a balloon, contain the cerebrospinal fluid that protects the brain from minor hits.
The Dural arteries provide oxygen-rich high-pressure blood to the brain, while the dural veins return oxygen-depleted (deoxygenated) low-pressure blood to the heart. High-pressure arterial blood enters into the veins or sinuses that normally handle low-pressure blood returning to the heart during a DAVF. This can cause ruptures, resulting in bleeding, brain hemorrhage, and other neurological problems. Dural AVFs are more common later in life (50 to 60 years of age).
Causes:
Dural AVFs and carotid-cavernous fistulas (CCFs) are two forms of AVFs that are acquired rather than hereditary. Infections or traumatic injuries can cause AVFs. However, the exact reason for AVFs is unknown.
Symptoms:
Patients with DAVFs may experience no symptoms at all. When symptoms do present, they might range from mild to severe. The symptoms are determined by the DAVF’s location and drainage pattern.
Symptoms of Dural AVF are:
- Headache
- Pulsatile tinnitus (ringing in the ears)
- Visual difficulty
- Seizures
- Bruit (sound heard due to unusual blood flow)
Can dAVF cause brain damage (or) Stroke/ Brain hemorrhage?
DAVF can over time develop aggressive symptoms like seizures, increased brain pressure with headaches nausea and vomiting (or) cause speech issues, and weakness.
More aggressive DAVF can rupture and cause bleeding in the brain called hemorrhage. These patients will develop sudden very severe headaches with varying symptoms of stroke – neurological disability. Most typically drooping face, arm (or) leg, difficulty speaking (or) becoming confused or sleepy.
Diagnosis:
An Interventional Radiologist may recommend diagnostic imaging (radiology) tests if you have signs or symptoms of a dural arteriovenous fistula(Dural AVF).
Diagnosis of Dural AVF may include:
- CT Scan
- MRI Scan
- Digital Subtraction Angiography (DSA)
Endovascular Embolization:
Endovascular embolization is a minimally invasive procedure commonly used to treat dural arteriovenous fistulas. It’s the first line of treatment in most dural AVFs.
How Is Endovascular Embolization Done?
Embolization of a DAVF is performed under general anesthesia. A catheter is inserted into an artery (usually the femoral artery in the front of the hip in the thigh ) to perform this treatment. The small tube-like structure or catheter is taken into the fistula location, guided by fluoroscopic or X-ray imaging. A contrast/due is injected to help in seeing the AVF’s exact location. Then an embolizing or blocking material injects is injected into the exact spot where the artery and vein meet to block the fistula. The most commonly used embolization material is a peculiar agent called Onyx. The AVF is cured after the connection between the artery and the vein is closed, and it rarely recurs.
Other treatment options include microsurgical excision and stereotactic radiosurgery.
Frequently Asked Questions:
Q: Can Dural Arteriovenous Fistula be cured?
A: Yes. Endovascular embolism treatment is usually suggested as the first line of treatment for DAVF. The patient is cured of DAVF using both transvenous and transarterial procedures.
Q: What are the risks of surgical treatment of DAVF?
A: DAVF with cortical venous drainage can have a relatively high risk of recurrent neurological events or hemorrhage.
Q: Can DAVFs recur after treatment?
A: DAVF recurrence may happen despite the initial cure. There may be a delay in recurrence if there is incomplete penetration of the embolic material into the proximal portion of the venous outlet.
Q: What are the risks of endovascular treatment of DAVF?
A: Periprocedural complications can happen in 5-10% if cases, which include brain hemorrhage, and brain swelling.
Q: What happens if you don’t treat the fistula?
A: An untreated dural AVF over a period of time may convert itself from a benign type more aggressive type and may cause a catastrophic brain hemorrhage.
About the Author:
Name: DR . SURESH GIRAGANI
INTERVENTIONAL RADIOLOGIST
DR. SURESH GIRAGANI CONSULTANT INTERVENTIONAL RADIOLOGIST at Yashoda group of hospitals has more than sixteen years of clinical experience in vascular interventions with a special interest in neurovascular and peripheral vascular disease interventional procedures.