Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

INITIAL

associated hematoma if significant mass effect

1st line – surgical evacuation of intracerebral hematoma

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INITIAL
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associated hematoma if significant mass effect
1st line – 

surgical evacuation of intracerebral hematoma

In patients with a ruptured arteriovenous malformation (AVM), emergent surgical evacuation of the intracerebral hematoma and control of acute bleeding may be required.[61]

Resection of deep or complex AVMs should be deferred and undertaken as a semi-elective procedure.[61] During an acute ICH episode, blood pressure lowering and reduction in blood pressure variability can reduce hematoma expansion with improved functional outcomes.[45] See Hemorrhagic stroke.

Consider – external ventricular drain

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INITIAL
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associated hematoma if significant mass effect
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with hydrocephalus
Consider – 

external ventricular drain

Treatment recommended for SOME patients in selected patient group

Hydrocephalus secondary to intraventricular rupture of the AVM may require treatment with an external ventricular drain.

ACUTE

not surgical candidate

1st line – conservative management

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ACUTE
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not surgical candidate
1st line – 

conservative management

Very large AVMs in eloquent locations (areas of the brain that control speech, motor function, and senses) with deep venous draining veins from the intracranial circulation should be managed conservatively with symptomatic treatment of the effects of the AVM such as seizure control.

2nd line – palliative embolization

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ACUTE
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not surgical candidate
2nd line – 

palliative embolization

Occasionally, palliative embolization can be offered with the aim of reducing shunt volume in the nidus to control seizures or reduce focal hypoxia ("vascular steal").

surgical candidate

1st line – surgical resection

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ACUTE
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surgical candidate
1st line – 

surgical resection

Surgical resection without embolization may be the only treatment modality required for small, superficially placed AVMs in noneloquent locations. Larger AVMs are more likely to require multimodality treatment.

A craniotomy is performed to expose the AVM, which is removed using standard microsurgical techniques to circumferentially excise the nidus. Feeding arterial vessels are sacrificed to the nidus itself using bipolar diathermy forceps and microscissors until the nidal draining veins are completely dearterialized. Once this has been achieved the draining vein may be taken and the nidus removed. Intraoperative neuronavigation is often used to localize the AVM nidus; alternatively, where a superficial arterialized draining vein is present on the cortical surface, this can be followed into the nidus.

Consider – staged embolizations

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ACUTE
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surgical candidate
Consider – 

staged embolizations

Treatment recommended for SOME patients in selected patient group

Larger AVMs usually require planned, often staged, embolizations followed by surgical excision or stereotactic radiosurgery for any residual AVM. Occasionally embolization can be done first on deep arterial feeders, which are difficult to reach surgically but easy to reach endovascularly.

A detailed angiographic analysis of the arteries supplying the AVM, supplemented if necessary with superselective angiography, is an essential precursor to treatment planning.

Embolizations are usually performed under general anesthesia through a femoral artery approach. N-butyl cyanoacrylate is a fast-polymerizing liquid adhesive embolic agent. However, its use has been largely supplanted by the Onyx liquid embolic system, which is less adhesive and polymerizes slowly, allowing for a more controlled embolization of the nidus.[67] Other liquid embolics, such as precipitating hydrophobic injectable liquid (PHIL) and squid (a nonadhesive liquid embolic agent composed of ethylene vinyl alcohol copolymer), are also available.[68][69]

Regardless of choice, there is a risk of reflux of the embolization agent into a feeding artery, which can result in stroke, and early obliteration or thrombosis of the draining veins can lead to periprocedural AVM rupture.[67][69]

1st line – stereotactic radiosurgery

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ACUTE
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surgical candidate
1st line – 

stereotactic radiosurgery

People with AVMs that are not surgically accessible, or in whom the overall risk of surgery outweighs that for other treatment modalities, may require treatment with stereotactic radiosurgery (SRS) with or without embolization.

SRS using either linear accelerator-based (LINAC) radiosurgery or the "gamma knife" enables precise delivery of a high dose of radiation to a small intracranial target while sparing the surrounding normal brain. It is usually given as a single dose. Although noninvasive, the procedure does carry risks. In particular, LINAC radiosurgery takes between 2 and 5 years to obliterate the AVM, so the patient is at risk of rebleeding during this period.[62]

Small size, noneloquent location, low-flow pattern, and absence of perinidal angiogenesis are predictors of obliteration by radiosurgery.[14] Typically, AVMs with a diameter of less than 3 cm (volume <10 cm³) are suitable for SRS.[59]

The use of SRS specifically in Spetzler-Martin grade 1 and 2 AVMs appears to achieve obliteration in 80% of patients, with post-treatment hemorrhage occurring in 6%.[63]​ 

Larger AVMs can be treated in several stages over 3 to 6 months;[64] staging may reduce the permanent adverse effects of radiation.[65]

AVM-associated aneurysms are strong predictors of post SRS hemorrhage. It is recommended to treat AVM associated aneurysms via microsurgery or endovascular therapy before SRS to reduce risk of hemorrhage.[61]

Consider – staged embolizations

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ACUTE
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surgical candidate
Consider – 

staged embolizations

Treatment recommended for SOME patients in selected patient group

AVMs associated with intranidal or extranidal aneurysms or arteriovenous fistulas may be resistant to radiosurgery, and have a higher incidence of perioperative hemorrhage.[81] When performed by experienced surgeons, embolization prior to radiosurgery may be considered for carefully selected patients with large, complex AVM.[82]

The specific goals of prestereotactic radiosurgery (SRS) embolization include making SRS feasible by reducing the nidus volume, and minimizing bleeding risk in the latency period by embolizing weak elements in the angioarchitecture of the nidus, such as flow-related aneurysms or high-flow fistulas.[79][80] The embolization should aim to produce a compact, stable nidus.

Systematic reviews and meta-analyses report lower AVM obliteration rates in patients who have undergone embolization followed by SRS than in those who have undergone SRS alone.[71][72][73] Increased treatment failure in patients who received pre-SRS embolization may be attributable to several causes: a failure to account for differences in AVM characteristics between patients who underwent embolization followed by SRS and those who had SRS alone (most studies are nonrandomized and retrospective); patients with complex AVMs being more likely to be candidates for prestereotactic radiosurgery embolization; embolization agents causing significant imaging artifact, thereby obscuring AVM visualization; and recanalization after embolization.[74][75][76][77][78]

A detailed angiographic analysis of the arteries supplying the AVM, supplemented if necessary with superselective angiography, is an essential precursor to treatment planning.

Embolizations are usually performed under general anesthesia through a femoral artery approach. N-butyl cyanoacrylate is a fast-polymerizing liquid adhesive embolic agent. However, its use has been largely supplanted by the Onyx liquid embolic system, which is less adhesive and polymerizes slowly, allowing for a more controlled embolization of the nidus.[67] Other liquid embolics, such as precipitating hydrophobic injectable liquid (PHIL) and squid (a nonadhesive liquid embolic agent composed of ethylene vinyl alcohol copolymer), are also available.[68][69]

Regardless of choice, there is a risk of reflux of the embolization agent into a feeding artery, which can result in stroke, and early obliteration or thrombosis of the draining veins can lead to periprocedural AVM rupture.[67][69]

1st line – endovascular embolization

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ACUTE
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surgical candidate
1st line – 

endovascular embolization

Small AVMs with easily accessible feeding vessels may be treated by endovascular embolization alone. However, the cure rate with embolization alone is moderate, with an average of 20% with n-butyl cyanoacrylate (n-BCA) in older studies, and up to 50% with newer embolic agents.[59]

A detailed angiographic analysis of the arteries supplying the AVM, supplemented where necessary with superselective angiography, is an essential precursor to treatment planning.

Embolizations are usually performed under general anesthesia through a femoral artery approach. n-BCA is a fast-polymerizing liquid adhesive embolic agent. However, its use has been largely supplanted by the Onyx liquid embolic system, which is less adhesive and polymerizes slowly, allowing for a more controlled embolization of the nidus.[67] Other liquid embolics, such as precipitating hydrophobic injectable liquid (PHIL) and squid (a nonadhesive liquid embolic agent composed of ethylene vinyl alcohol copolymer), are also available.[68][69]

Regardless of choice, there is a risk of reflux of the embolization agent into a feeding artery, which can result in stroke, and early obliteration or thrombosis of the draining veins can lead to periprocedural AVM rupture.[67][69]

pregnant

1st line – multidisciplinary care

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ACUTE
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pregnant
1st line – 

multidisciplinary care

Management of pregnancy and labor in women with AVMs requires a multidisciplinary team. Risk of intrapartum intracranial bleeding is considered low if the AVM is fully treated or intracranial bleed occurred more than 2 years ago.[90] Women at low risk of intracranial bleed can base decisions on mode of delivery based on their usual preference and obstetric indications. Risk of intrapartum intracranial bleed is high if the mother has an untreated or complex AVM or hemorrhagic episode in the past 2 years. Mothers at high risk of intracranial bleed should be offered the option of cesarean section after full discussion of the benefits and risks of each option. Women at high risk who prefer to attempt vaginal birth should be offered regional analgesia and offered the option of assisted second stage of delivery.[90]

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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