Arteriovenous malformations of the brain

Marc-Alain Babi MD (Dr. Babi of the University of Florida has no relevant financial relationships to disclose.)
Darin Ftouni MD (Dr. Ftouni of the University of Florida has no relevant financial relationships to disclose.)
Steven R Levine MD, editor. (

Dr. Levine of the SUNY Health Science Center at Brooklyn has received honorariums from Genentech for service on a scientific advisory committee and a research grant from Genentech as a principal investigator.

)
Originally released June 9, 2014; last updated January 3, 2018; expires January 3, 2021

This article includes discussion of arteriovenous malformations of the brain, brain arteriovenous malformations, AVMs, cerebral arteriovenous malformations, cAVMs, and CNS arteriovenous malformations. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Overview

Cerebral arteriovenous malformations are the most dangerous congenital vascular malformations of the nervous system (Mohr et al 2014). Brain arteriovenous malformations are the underlying cause of 1% to 2% of all strokes, 3% of strokes in young adults, and around 10% of all subarachnoid hemorrhages (Al-Shahi and Warlow 2001; Friedlander 2007). They occur in about 0.1% of the population and one tenth of all intracranial aneurysms (Mohr et al 2014). Brain arteriovenous malformations are mostly asymptomatic, though these lesions can be brought into clinical attention with a variety of neurologic complaints, including headaches, seizures, or progressive neurologic deficits or by incidental discovery (Derdeyn et al 2017). Short-term morbidity and mortality associated with arteriovenous malformations are low, but patients may do poorly in the long-term given the cumulative risk of hemorrhage. In determining the need for intervention, morphologic and clinical characteristics, such as age, size, location, vascular features, and, most importantly, the risk of hemorrhage of the arteriovenous malformations are considered key (Barr and Ogilvy 2012). In 2013, the first large-scale randomized clinical trial comparing medical and interventional management of unruptured brain arteriovenous malformations, the ARUBA trial, was published. The purpose of this article is to discuss the clinical manifestations, pathophysiology, diagnosis, prognosis, and management of 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 angiography, imaging modalities, and microsurgical techniques, the understanding of and treatment options for these lesions have since grown. Modern categorization and nomenclature of CNS vascular malformations was established by McCormick in 1966. This system used histopathologic features to classify each lesion as a venous angioma, cavernous malformation, capillary telangiectasia, or arteriovenous malformation. The Spetzler-Martin grading system for brain arteriovenous malformations used major factors influencing the risk of surgical resection and hemorrhage to score the arteriovenous malformations (Spetzler and Martin 1986). It is the most commonly used grading system that helps clinicians make treatment decisions and offers a standardized way of classifying arteriovenous malformations for literature and research. Of note, a new supplementary scoring system to the traditional Spetzler-Martin grading scale was published whereby patient age (younger than 20 years=1 point; 20 to 40 years=2 points; older than 40 years=3 points), bleeding or hemorrhagic presentation (yes=0 points; no=1 point), and nidus configuration (compact=0 points; diffuse=1 point) were added to the grading system (Kim et al 2015). This Lawton-Young supplementary grading scale was shown to be more accurate at neurologic patient outcome than the Spetzler-Martin system alone and achieves more even surgical risk stratification (Morgan et al 2017).

Table 1. Spetzler-Martin Grading Scale for Arteriovenous Malformations

Characteristic

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

Location
Non-eloquent site
Eloquent site

0 points
1 point

Pattern of venous drainage
Superficial only
Deep only

0 points
1 point

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