INTRACEREBRAL HEMORRHAGE / VASCULAR MALFORMATIONS
Dural arteriovenous fistula (DAVF)
Created 21/04/2021, last revision 22/01/2023
- dural arteriovenous fistula (DAVF) is characterized by abnormal connections (shunts) between an artery and a vein; DAVF usually presents with tinnitus, hemorrhage, or venous hypertension
- DAVF accounts for about 10-15% of vascular malformations; it mostly affects patients aged 40-60 years
- most DAVFs are idiopathic; some patients have a history of previous craniotomy, head trauma, or dural sinus thrombosis [Gandhi, 2012]
Pathology
Pathology- commonly, multiple feeders are present
- supratentorial
- middle meningeal artery, superficial temporal artery (ECA)
- ethmoidal branches of the ophthalmic artery
- cavernous sinus (ICA and/or ECA branches) → carotid-cavernous fistula (CCF)
- posterior fossa
- vertebral arteries
- occipital artery (ECA)
- supratentorial
- most typical drainage:
- transverse/sigmoid sinus (usually fed from the occipital artery) → anatomy of cerebral veins and sinuses
- cavernous sinus (carotid-cavernous fistula)
- SSS
- straight sinus
- cortical veins
Classification
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Clinical presentation
Clinical presentation is variable and depends on the fistula location and venous drainage
- pulsatile tinnitus (typically with sigmoid and transverse sinus drainage)
- symptoms of venous hypertension/congestion
- headache
- hemorrhagic venous infarction
- spinal myelomalacia
- cranial nerve palsies
- ocular (orbital) symptoms – conjunctival chemosis and swelling (carotid-cavernous fistula) – DDx of cavernous sinus thrombosis!
- intracerebral or subarachnoid hemorrhage (high risk, especially in type II and III) [Li, 2015]
- type II and III have an annual risk of ~8% [Gandhi, 2012]
- DAVF can be high flow and consume a significant portion of EF => exertional dyspnea, left ventricular hypertrophy (LVH)
Diagnostic evaluation
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Management
- treatment decision is based on:
- type of the fistula
- patient’s age and comorbidities
- presence of symptoms attributable to the fistula
Conservative treatment
- usually in Borden I, Cognard I and IIa
- in mild cases, intermittent external compression of the feeding artery can be helpful (retroauricular compression in DAVF fed by the occipital artery)
Endovascular and surgical treatment
- an indisputable indication is DAVF Borden types II and III or Cognard IIb-V because of the high risk of bleeding (an annual risk of ~8%)
- type I with severe tinnitus may also be indicated for endovascular treatment
Endovascular treatment
- transarterial approach (TAE) – super-selective distal catheterization
- e.g. Onyx [Lv, 2009]
- transvenous approach (TVE) – mainly in multiple small feeding arteries, unsuitable for embolization
- combined approach (TAE + TVE)
Surgery
- if endovascular treatment is not possible or the procedure was unsuccessful or only partially successful
Stereotactic radiosurgery (SRS)
- 20-30 Gy ⇒ irradiated vessels get thrombosed
- obliteration is gradual (within 2-3 years)
- unsuitable as primary treatment if reflux into cortical veins is present
