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Brain Arteriovenous Malformations in Adults Eric Johnson OHSU MS3 12/14/07 The story of AVMs is an interesting one, because . . . Although rare, they can be fatal ... – PowerPoint PPT presentation

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Title: Brain Arteriovenous Malformations in Adults


1
Brain Arteriovenous Malformations in Adults
  • Eric Johnson
  • OHSU MS3
  • 12/14/07

2
The story of AVMs is an interesting one, because
. . .
  • Although rare, they can be fatal
  • Some AVMs are discovered incidentally in
    asymptomatic individuals
  • Our treatment modalities for AVMs have evolved
    faster than our knowledge about their incidence,
    prevalence and natural history

3
  • Widely accepted surgical treatments have
    significant risks (neurological deficits, death)
  • There are no prospective, randomized trials
    comparing surgical treatments to conservative
    medical treatments, or even no treatment (a
    control population)
  • However, many (most?) AVMs are treated surgically
    (even in asymptomatic individuals)

More about this later . . .
4
Definition of an AVM
  • A congenital shunt between the arterial and
    venous systems
  • A tangle of abnormal vessels (nidus)
  • Vary in size and location

http//neuro.wehealny.org/endo/illus/13_01.gif
5
Epidemiology and Natural History
(These figures are debated in the literature)
  • Incidence about 1 per 100,000 per year
  • Point prevalence about 18 per 100,000
  • AVMs account for
  • 1-2 of all strokes
  • 9 of subarachnoid hemorrhages
  • Annual risk of hemorrhage from unruptured AVM
    about 2 (poor data)
  • Risk of recurrent hemorrhage up to 18 in the
    first year, uncertain thereafter (poor data)
  • Annual case fatality 1-1.5 (poor data)

(Al-Shahi et al.)
6
Pathogenesis
  • Poorly understood
  • Genetic variation may play a role (Hashimoto et
    al.)

7
Pathology
  • AVMs divert blood flow from surrounding brain
    parenchyma
  • This leads to areas of chronic ischemia,
    producing gliotic tissue
  • AVM vessels have abnormal internal elastic lamina
    and/or media, making them prone to rupture

Kumar et al.
8
Clinical Presentation
  • Most commonly present before age 40, some with
    more than one symptom
  • 53 hemorrhage
  • 30 generalized seizure
  • 14 chronic headache
  • 10 focal seizures
  • 7 persistent neurological deficits
  • 5 progressive neurological deficits
  • About one-fifth are discovered incidentally in
    asymptomatic individuals

Hofmeister et al.
Al-Shahi and Warlow
9
Diagnosis
  • Diagnosis is made or confirmed by diagnostic
    imaging
  • Angiography is considered the gold standard for
    diagnosis and treatment planning
  • However, there is very little data about the
    sensitivity and specificity, as well as intra-
    and inter-observer variability of imaging
    modalities used to diagnose and classify AVMs

10
CT Imaging
  • What to look for
  • Vascular tangles that are serpiginous and
    possibly hyperdense, due to the pooling of blood
  • May contain punctate or curvilinear
    calcifications
  • AVMs will enhance with contrast
  • An AVM may present as a hemorrhage

11
  • Axial
  • CT
  • without
  • contrast

Al-Shahi et al.
12
  • Axial
  • CT
  • with
  • contrast

Al-Shahi et al.
13
  • Axial
  • CT
  • with
  • hemorrhage
  • secondary
  • to AVM

http//www.brain-aneurysm.com/images/avm_pageimage
s/3.jpg
14
MRI Imaging
  • What to look for
  • Curvilinear flow-voids

15
  • Coronal,
  • unenhanced,
  • T1- weighted
  • MRI

Al-Shahi et al.
16
  • Saggital,
  • T1-weighted
  • MRI

http//www.hmc.psu.edu/neurosurgery/services/image
s/LF1.jpg
17
Angiography
  • What to look for
  • The three components of an AVM
  • Enlarged feeding artery
  • Core/nidus
  • Enlarged draining vein
  • Early venous filling during the arterial phase of
    enhancement

18
  • Cerebral
  • angiogram
  • ICA Internal
  • carotid artery
  • MCA Middle
  • cerebral artery
  • DV Draining vein
  • Arrows AVM nidus

http//www.brain-aneurysm.com/images/avm_pageimage
s/4.jpg
19
  • Cerebral
  • angiogram

http//www.ucl.ac.uk/medical-modelling/myimages/Fi
gure1.jpg
20
Treatment
  • Surgical options include
  • Neurosurgery (resect the AVM)
  • Sterotactic radiosurgery (ablate the AVM through
    direct radiation, which causes thrombosis over
    time)
  • Endovascular embolization (ablate AVM through
    direct thrombosis with embolic material)
  • A combination of these modalities
  • AVMs are graded in an effort to help guide
    treatment decisions. The most common grading
    system is the Spetzer-Martin Scale

21
Spetzler-Martin AVM Grading Scale
  • Size
  • 0-3 cm 1
  • 3.1-6.0 cm 2
  • gt6 cm 3
  • Location
  • Noneloquent 0
  • Eloquent 1
  • Deep venous drainage
  • Not present 0
  • Present 1

Eloquent brain regions can be defined as
sensorimotor, language, and visual cortex the
hypothalamus and thalamus the internal capsule
the brain stem the cerebellar peduncles and the
deep cerebellar nuclei. (Hofmeister et. al)
Grading scale adapted from Ogilvy et al.
22
Neurosurgery
  • Primarily for Spetzler-Martin grade 1 and 2
    lesions (Ogilvy et al.)
  • For complications, one study reported that 8 of
    patients either had a persistent neurological
    deficit or died as a result of surgery (Mohr et
    al.)

23
Stereotactic Radiosurgery
  • Primarily for small AVMs, especially in eloquent
    brain locations (Ogilvy et al.)
  • Friedman et al. reported the following
    complication rates
  • 10 post-treatment hemorrhage
  • 3.7 transient radiation-induced complication
  • 1 permanent radiation-induced complication

24
Endovascular Embolization
  • Primarily a presurgical modality for large
    cortical AVMs to reduce nidus size (Ogilvy et
    al.)
  • Palliative embolization may be used in large
    nonsurgical or nonradiosurgical AVMs (Ogilvy et
    al.)
  • Complication rate (Mohr et al)
  • Morbidity 13
  • Mortality 2

25
Some quotes from UpToDate
  • Surgery is the mainstay of treatment
    radiosurgery is a useful option . . . and
    endovascular embolization has become a useful
    adjunct to these techniques.
  • There is no evidence from randomized clinical
    trials to guide treatment decisions.
  • There are no randomized controlled trials of
    radiosurgery for brain AVMs, and none are likely
    to be performed as the benefit of radiosurgery
    for radiographic obliteration of brain AVMs is
    widely accepted. (Singer et al.)

26
From the Cochrane Collaboration
  • There is no clear evidence from randomised
    trials with clear clinical outcomes, comparing
    different interventional treatments for brain
    AVMs against each other or against usual medical
    therapy, to guide the interventional treatment of
    brain AVMs in adults. (Al-Shahi and Warlow)

27
But theres hope . . .
  • A Randomized Trial of Unruptured Brain AVMs (the
    ARUBA trial) is currently recruiting
    participants
  • Current treatments are administered on the
    assumption that they can be achieved at
    acceptably minor complication rates, decrease the
    risk of subsequent hemorrhage, and lead to better
    long-term outcomes.
  • Therefore, the purpose of this study is to
    determine if medical management is better than
    invasive therapy for improving the long-term
    outcome of patients with unruptured brain
    arteriovenous malformations.

http//clinicaltrials.gov/ct/show/NCT00389181?orde
r2
28
Summary
  • Because AVMs are rare, little is understood about
    their epidemiology and natural history
  • Because they cause significant morbidity and
    mortality, they are often treated
  • Commonly used treatments for AVMs also cause
    significant morbidity and mortality
  • Patients are being treated in the absence of a
    sufficient cost-benefit analysis regarding those
    treatments

29
  • We need more research on classifying AVMs based
    on radiological findings that are consistent and
    reproducible among radiologists
  • We also need more research comparing treatments
    to a control population and to each other for
    different classes of AVMs
  • Stay tuned for the results of the ARUBA Trial!

30
Bibliography
  • Al-Shahi et al. A systematic review of the
    frequency and prognosis of arteriovenous
    malformation of the brain in adults. Brain.
    2001 1241900-1926.
  • Al-Shahi R, Warlow CP. Interventions for treating
    brain arteriovenous malformations in adults.
    Cochrane Database of Systematic Reviews 2006,
    Issue 1. Art. No. CD003436. DOI
    10.1002/14651858.CD003436.pub2.
  • Friedman, et al. Analysis of factors predictive
    of successor complications in arteriovenous
    malformation radiosurgery. Neurosurgery. 2003
    52296-308.
  • Hashimoto et al. Gene microaray analysis of
    human brain arteriovenous malformations.
    Neurosurgery. 2004 54410.
  • Hofmeister et al. Demographic, Morphological,
    and Clinical Characteristics of 1289 Patients
    With Brain Arteriovenous Malformation. Stroke.
    2000 311307-1310.
  • Kumar et al. Pathologic basis of Disease, 7th
    Edition. Elsevier Saunders Philadelphia, PA.
    2005.
  • Mohr et al. Arteriovenous malformations of the
    brain in adults. NEJM. 1999 2301812-1818.
  • Ogilvy et al. Recommendations for the
    Management of Intracranial Arteriovenous
    Malformations Stroke. 2001 321458-1471.
  • Singer et al. Brain arteriovenous
    malformations. UpToDate Online 2007.
  • The ARUBA Trial. lthttp//clinicaltrials.gov/ct/sho
    w/NCT00389181?order2gt
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