Dural arteriovenous fistulas

Diagnosis

If you have signs or symptoms of a dural arteriovenous fistula, your doctor may recommend that you undergo diagnostic imaging (radiology) tests. For dural arteriovenous fistulas, these may include:

• Initial imaging. Initial evaluation typically includes cross-sectional imagery from noncontrast head computerized tomography (CT) and magnetic resonance imaging (MRI).
• CT head scans. These tests can show fluid buildup caused by heightened cortical vein blood pressure as well as actual bleeding, which may be caused by a dAVF but occur elsewhere in the brain's venous system.
• MRIs. These images can establish the shape and extent of a dAVF, detect any micro-hemorrhages (very small bleed locations), and determine the impact of any abnormal blood vessel structures related to the fistula itself.
• Angiography. Catheter-based cerebral angiography (also known as digital subtraction angiography) is still the most reliable and definitive tool on dAVF diagnosis. It's essential for defining:
  • How many fistulae exist and where
  • Anatomy of the external carotid arteries and any branches between them and the dura
  • Fistula blood vessels' structure
  • Whether cardiovascular disease is also present
  • How much narrowing or blockage has occurred in the dural sinus
  • Whether any affected veins are dilated and to what extent

Superselective angiography may also be required to identify the area of convergence of the feeding dural arteries and the origin of the draining vein.

Treatment

Treatment for dural arteriovenous fistula generally involves surgery to block or disconnect the fistula.

Dural arteriovenous fistula surgery

• Endovascular procedures. In an endovascular procedure, your doctor may insert a long, thin tube (catheter) into a blood vessel in your leg or groin and thread it through blood vessels to the dural arteriovenous fistula using X-ray imaging.

  Your doctor inserts the catheter into the blood vessel that leads to the dAVF and releases coils or a glue-like substance to block the abnormal connection in the blood vessels.

• Stereotactic radiosurgery. In stereotactic radiosurgery your doctor uses precisely focused radiation to block the abnormal connection in the blood vessels. The high dose of radiation delivered to the fistula causes blood vessels to close off, destroying the dAVF. The different types of technology used to perform dAVF stereotactic radiosurgery include the linear accelerator (LINAC), Gamma Knife and proton beam therapy.
• dAVF surgery. If an endovascular procedure or stereotactic radiosurgery aren't options for you, you may need dAVF surgery. Surgery may be performed to disconnect the dAVF or cut off the blood supply and remove the fistula.

Preparing for your appointment

What you can do

• Keep a detailed symptoms calendar. Each time a symptom occurs, write down the date and time, what you experienced and how long it lasted.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of all medications, vitamins or supplements that you're taking.
• Take a family member or friend along. Sometimes it can be difficult to remember all the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Bring along any recent brain scans in a CD to your appointment. Also, if you've experienced seizures, your doctor may want to ask questions of someone who has witnessed them, as it's common not to be aware of everything that happens when you experience one.

Write down questions to ask your doctor.

Preparing a list of questions will help you make the most of your time with your doctor. List your questions from most important to least important in case time runs out. Most of these would be covered during your visit. Some examples of good questions to ask your doctor include:

General Questions

• Where is the fistula located?

Management and observation

• Will I need follow-up tests?
• If so, how often will I follow up with you?

Surgery (to disconnect a fistula)

• How long would you estimate I'd be in surgery?
• How long does surgery recovery usually take?
• How long should I plan to be in the hospital?

Surgical background

• How many dAVFs have you seen and how many have you treated?
• Does your institution have a cerebrovascular specialty practice?

In addition to the questions you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.

What to expect from your doctor

Your doctor is also likely to ask you a number of questions:

• When did you first begin experiencing symptoms (for example, hearing or vison problems, seizures, speech issues, palsies, or other symptoms)?
• Do your symptoms come and go (intermittent) or are they persistent?
• Do your symptoms seem to be triggered by certain events or conditions?

What you can do in the meantime

Certain conditions and activities can trigger seizures, so it may be helpful to:

• Avoid excessive alcohol consumption
• Avoid nicotine usage
• Get enough sleep
• Reduce stress