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  • Updated 07.20.2022
  • Released 06.09.2014
  • Expires For CME 07.20.2025

Arteriovenous malformations of the brain



Cerebral arteriovenous malformations are congenital vascular malformations in the brain that are the underlying cause of 1% to 2% of all strokes, 4% of strokes in young adults, 9% of subarachnoid hemorrhages, and 4% of intracerebral hemorrhages (02; 45). Brain arteriovenous malformation detection rate in a random-effects metaanalysis was 1.31 per 100,000 person-years, and in the largest case series, the prevalence of brain arteriovenous malformation-associated aneurysms was 10% to 20% (22). With regards to intracerebral hemorrhage, there is a 9.8% per year risk of cerebral arteriovenous malformations hemorrhage in patients with intranidal aneurysms, which is higher than the overall population of patients with cerebral arteriovenous malformations (22).

Though mostly asymptomatic, these lesions come to clinical attention with a variety of neurologic presentations, including headaches, seizures, progressive neurologic deficits, or by incidental discovery (16). Short-term morbidity and mortality associated with arteriovenous malformations are typically low, although poor outcomes may occur in the long-term given the cumulative risk of hemorrhage. In determining the need for intervention, key morphologic and clinical characteristics are considered, such as age, size, location, vascular features, and most importantly, the estimated risk of hemorrhage (04). InWhen published in 2013, the first large-scale randomized clinical trial comparing medical and interventional management of unruptured brain arteriovenous malformations, the ARUBA trial, showed that medical management alone remained superior to interventional therapy for the prevention of death or symptomatic stroke, even up to 5 years follow-up (44). The purpose of this article is to discuss the clinical manifestations, pathophysiology, diagnosis, prognosis, and management of cerebral arteriovenous malformations.

Key points

• Cerebral arteriovenous malformations are congenital vascular malformations in the brain that result in direct connections between arteries and veins, without intervening capillary beds.

• Cerebral arteriovenous malformations are relatively uncommon, but a notable, cause of intracranial hemorrhage, especially in younger adults.

• Most cerebral arteriovenous malformations are asymptomatic and are discovered incidentally with neuroimaging.

• Cerebral arteriovenous malformations are reliably identified by CT and MR angiography, but conventional angiography remains the definitive diagnostic modality.

• Interventions for cerebral arteriovenous malformations include surgical resection, stereotactic radiotherapy, and endovascular embolization.

• Management decisions and risk prognosis differ between unruptured and ruptured cerebral arteriovenous malformations.

Historical note and terminology

Vascular malformations of the central nervous system (CNS) have been described in the literature dating back to the 19th century. With advances in imaging modalities and microsurgical techniques, the understanding of and treatment options for these lesions have expanded. Modern categorization and nomenclature of CNS vascular malformations was established by McCormick in 1966, using histopathologic features to classify each lesion as a venous angioma, cavernous malformation, capillary telangiectasia, or arteriovenous malformation. The Spetzler-Martin grading system (Table 1) for cerebral arteriovenous malformations takes into account major factors influencing the risk of surgical resection and hemorrhage (67). It is the most commonly used grading system, helping clinicians make treatment decisions and offering a standardized classification terminology. A supplementary scoring system was published in 2010 taking into account additional components: age at resection, hemorrhage before resection, and diffuseness of the arteriovenous malformations nidus. This supplementary grading scale (also known as the Lawton-Young Grading System) was found to be more accurate at predicting neurologic patient outcome than the Spetzler-Martin system alone and further clarified surgical risk stratification (46). It was further validated, even with a higher proportion of high-grade arteriovenous malformations; however, perforators play important role on the outcome (30). During arteriovenous malformation resection, there is significant difficulty with coagulation of these perforators, and these vessels can retract into the white matter. This is seen with large complex arteriovenous malformations, and the perforators that were studied were medial lenticulostriates, insular lenticulostriates, thalamoperforators, and brainstem perforators (30).

Table 1. Spetzler-Martin Grading Scale for Arteriovenous Malformations


Number of points assigned

Size of arteriovenous malformation
Small (< 3 cm)
Medium (3 to 6 cm)
Large (> 6 cm)

1 point
2 points
3 points

Non-eloquent site
Eloquent site

0 points
1 point

Pattern of venous drainage
Superficial only
Deep only

0 points
1 point

Score = sum of all categories, with lesions graded 1 to 5 based on total sum (eg, 1 point = grade 1).

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