intracranial dural arteriovenous fistulas (davfs), an...

Intracranial dural arteriovenous fistulas (DAVFs), an educational review.

douglas choo pgy3

Intracranial dural arteriovenous fistulas – what are they?

•Pathologic shunts between duralarteries and duralvenous sinuses, meningeal veins, or cortical veins.

•Gold standard of dx is via angiogram.

Image credit: http://www.ajnr.org/content/33/6/1007.figures-only

As an introduction, here are some quick local examples of Dural arteriovenous fistulas as seen on various modalities:

A CT head with a Left Superior Petrosal DAVF:

A CTA of the same Left Superior Petrosal DAVF:

An enhanced CT head with a superior sagittal sinus DAVF

An non enhanced CT head with a R parietal DAVF

The same R parietal DAVF on a MRI Time of Flight sequence

The CT head can be difficult diagnostically.

Could you say that was not a hemangioblastoma?

The angiogram is the gold standard.

Here is the sameposterior fossa lesion as the previous slide, shown to be a DAVF via angiogram.

Dural arteriovenous fistulas – proposed etiologies

• Idiopathic

•Hx of craniotomy or trauma

•Sinus thrombosis which promotes neoangiogenesis

•Congenital.


Dural arteriovenous fistulas – natural history

•Accounts for 10-15% of all intracranial vascular lesions.

•Presentation symptoms include: Asymptomatic, Headache, Visual disturbance, Seizure, Tinnitus (often unilateral), Intracranial bruit, Dysarthria and Intracranial Hemmorage.

Dural arteriovenous fistulas – classification

•Drainage pattern determines severity of symptoms and is foundation of classification.

• 2 types of classification patterns: Bordenand Cognard.

Borden Classification

• The Borden classification stratifies based on the site of venous drainage and whether there is Cortical Venous Reflux .

•3 types:

Borden type I:

• DAVF drainage into a duralvenous sinus or meningeal vein with normal anterograde flow. No cortical venous reflux.

• Benign, but may still have bothersome symptoms to the patient (ex: tinnitus or ophthalmological sx). But only 2% risk of transforming to type II or III


Borden type II:

• Anterograde or retrograde drainage into dural venous sinus with cortical venous reflux.

• 20% present with ICH.


Borden type III:• Direct retrograde drainage of meningeal arteries into subarachnoid veins, with

cortical venous reflux. 40% present with ICH.


Borden Classification – in summary

Type Venous Drainage Site Cortical Venous Reflux

Benign:

Type 1 Dural Sinus or Cortical Vein No

Aggressive:

Type 2 Dural Sinus Yes

Type 3 Cortical Vein Yes

Borden Classification – in summary

• The most critical part of evaluating DAVF is whether or not there is Cortical Venous Reflux. It’s presence alone will characterize the lesion as aggressive (Borden II or III)

•With Cortical Venous Reflux annual mortality risk may be as high as 10.4%.

Cortical Venous reflux:

ECA

Middle Meningeal Art.

Dural AVF

Cortical venous reflux

Sigmoid sinus

Cognard Classification – another schemeType Venous Drainage Flow pattern in sinus Cortical Venous Reflux

Benign

I Dural Sinus Antegrade No

IIa Dural Sinus Retrograde No

Aggressive

IIb Dural Sinus Antegrade Yes

IIa+b Dural Sinus Retrograde Yes

III Cortical Vein Yes

IV Cortical Vein Yes + Venous Ectasia

V Cortical Vein with Spinal perimedullary drainage

Yes

Cognard Classification – a schemeType Venous Drainage Flow pattern in sinus Cortical Venous Reflux

Benign

I Dural Sinus Antegrade No

IIa Dural Sinus Retrograde No

Aggressive

IIb Dural Sinus Antegrade Yes

IIa+b Dural Sinus Retrograde Yes

III Cortical Vein Yes


V Cortical Vein with Spinal perimedullary drainage

Yes

The Cognard Classification adds Venous Ectasia

• Like Cortical Venous Reflux, it is a poor prognostic factor.

• Cognard Type IV

• According to a series of 205 patients by Cognard et al, 97% of the patients with Type IV DAVFs had aggressive neurological symptoms and 65% presented hemorrhage.

• Some studies conclude this may be the highest risk of hemorrhage for any intracranial vascular lesion.

Type Venous Drainage Flow pattern in sinus Cortical Venous Reflux

Aggressive


Venous ectasia:

Venous ectasia

Treatment options:• 1. Conservative treatment. Reserved only for Borden type 1 DAVF.

• 2. Stereotactic radiotherapy. Some small studies report complete occlusion in 44-87% of cases. Unfortunately there is an unacceptable delay of 1 – 3 years to achieve full occlusion. Some centers will combine it with other treatments.

• 3. Endovascular treatments. Usually the 1st line treatment. Traditionally Coiling and nBCA (glue) used. Onyx introduced in recent years.

• 4. Surgical obliteration via craniotomy. Used if endovascular treatment fails. Carries similar risks to other procedures involving craniotomy.

• Usually the 1st line treatment. Traditionally Coiling and nBCA (glue) were the main considerations. ONYX introduced in recent years.

• Several studies report ONYX to be as safe and in some cases superior to nBCA and glue.4,5,6,7,8,11,14,15,16,17,18,19

• Our local institution is completing a retrospective review and preliminary results also find ONYX to be as safe and superior to nBCAand coils in terms of not requiring post embolization surgery.

• Results will be formally presented at Dalhousie Radiology department’s research day in 2016.

Endovascular treatment of DAVF

What is ONYX?

• Onyx® is a non-adhesive liquid embolic agent.

• Onyx is made of a ethylene vinyl alcohol copolymer dissolved in dimethyl sulfoxide and suspended micronized tantalum powder (for contrast under fluoroscopy).

• FDA approved for DAVFs and AVMs in 2005.

Take home points:• A DAVF is a pathologic shunts between dural arteries and dural venous sinuses, meningeal veins,

or cortical veins.

• The CT head can be non conclusive for diagnosis.

• Angiogram is the Gold Standard for Dx.

• The presence Cortical Venous Reflux and Venous Ectasia classify the lesion as aggressive with a high ICH risk and mortality risk.

• 1st line treatment is endovascular embolization.

• Several studies support ONYX to be as safe and in some cases superior to nBCA and glue. Our institution’s retrospective findings support this. We will present out findings at Dalhousie Radiology Research day 2016.

1. Wong, G. K. C. et al. 'Transvenous Embolization For Dural Transverse Sinus Fistulas With Occluded Sigmoid Sinus'. Acta Neurochir (Wien) 149.9 (2007): 929-936.

2. Cognard, C. et al. 'Endovascular Treatment Of Intracranial Dural Arteriovenous Fistulas With Cortical Venous Drainage: New Management Using Onyx'. American Journal of Neuroradiology 29.2 (2008): 235-241.

3. van Dijk, J. M. C. et al. 'Clinical Course Of Cranial Dural Arteriovenous Fistulas With Long-Term Persistent Cortical Venous Reflux'. Stroke 33.5 (2002): 1233-1236.

4. Maimon, S. et al. 'Transarterial Treatment With Onyx Of Intracranial Dural Arteriovenous Fistula With Cortical Drainage In 17 Patients'. American Journal of Neuroradiology 32.11 (2011): 2180-2184.

5. Abud, T. G. et al. 'The Use Of Onyx In Different Types Of Intracranial Dural Arteriovenous Fistula'. American Journal of Neuroradiology 32.11 (2011): 2185-2191.

6. Long, X-A et al. 'Onyx 18 Embolisation Of Dural Arteriovenous Fistula Via Arterial And Venous Pathways: Preliminary Experience And Evaluation Of The Short-Term Outcomes'. BJR 85.1016 (2012): e395-e403.

7. Lv, Xianli et al. 'Embolization Of Intracranial Dural Arteriovenous Fistulas With Onyx-18'.European Journal of Radiology 73.3 (2010): 664-671.

8. Gupta, AK, and AL Periakaruppan. 'Intracranial Dural Arteriovenous Fistulas: A Review'. Indian Journal of Radiology and Imaging 19.1 (2009): 43.

9. Limaye, Uday et al. 'Embolization Of Cranial Dural Arteriovenous Fistulae With ONYX: Indications, Techniques, And Outcomes'. Indian Journal of Radiology and Imaging 20.1 (2010): 26.

10. Siekmann, W. Weber et al. ‘Transvenous Treatment of a Dural Arteriovenous Fistula of the Transverse Sinus by Embolization with Platinum Coils and Onyx HD 500+’ Interventional Neuroradiology 11 (2005) 281-286

References:

11. X Lv, C Jiang et al. ‘Percutaneous Transvenous Embolization of Intracranial Dural Arteriovenous Fistulas with Detachable Coils and/or in Combination with Onyx’ Interventional Neuroradiology 14 (2008) 415-427

12. J Zhang, X LV et al. ‘Transarterial and Transvenous Embolization for Cavernous Sinus Dural Arteriovenous Fistulae’Interventional Neuroradiology 16 (2010) 269-277

13. Oh, Jung Tae et al. 'Intracranial Dural Arteriovenous Fistulas: Clinical Characteristics And Management Based On Location And Hemodynamics'. Journal of Cerebrovascular and Endovascular Neurosurgery 14.3 (2012): 192.

14. Hu, Y. C. et al. 'Cranial Dural Arteriovenous Fistula: Transarterial Onyx Embolization Experience And Technical Nuances'. Journal of NeuroInterventional Surgery 3.1 (2011): 5-13.

15. De Keukeleire, K. et al. 'Transarterial Embolization With ONYX For Treatment Of Intracranial Non-Cavernous Dural Arteriovenous Fistula With Or Without Cortical Venous Reflux'. Journal of NeuroInterventional Surgery 3.3 (2011): 224-228.

16. Carlson, Andrew P., Christopher L. Taylor, and Howard Yonas. 'Treatment Of Dural Arteriovenous Fistula Using Ethylene Vinyl Alcohol (Onyx) Arterial Embolization As The Primary Modality: Short-Term Results'. Journal of Neurosurgery 107.6 (2007): 1120-1125.

17. Ihn, Yon Kwon et al. 'Dural Arteriovenous Fistula Involving An Isolated Sinus Treated Using Transarterial Onyx Embolization'. Journal of Korean Neurosurgical Society 52.5 (2012): 480.

18. Macdonald, Jason Hector Michael, John S. Millar, and C. S. Barker. 'Endovascular Treatment Of Cranial Dural Arteriovenous Fistulae: A Single-Centre, 14-Year Experience And The Impact Of Onyx On Local Practise'. Neuroradiology 52.5 (2009): 387-395.

19. Natarajan, Sabareesh K. et al. 'Multimodality Treatment Of Intracranial Dural Arteriovenous Fistulas In The Onyx Era: A Single Center Experience'. World Neurosurgery 73.4 (2010): 365-379. Web.

20. Borden, Jonathan A., Julian K. Wu, and William A. Shucart. 'A Proposed Classification For Spinal And Cranial Dural Arteriovenous Fistulous Malformations And Implications For Treatment'. Journal of Neurosurgery 82.2 (1995): 166-179. Web.

References (page 2):

intracranial dural arteriovenous fistulas (davfs), an...

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