Pathomechanisms of Symptomatic Developmental
Venous Anomalies
Vitor M. Pereira, MD; Sasikhan Geibprasert, MD; Timo Krings, MD, PhD;
Thaweesak Aurboonyawat, MD; Augustin Ozanne, MD; Frederique Toulgoat, MD;
Sirintara Pongpech, MD; Pierre L. Lasjaunias, MD, PhD
Downloaded from http://stroke.ahajournals.org/ by guest on June 14, 2017
Background and Purpose—Although it is generally accepted that developmental venous anomalies (DVAs) are benign
vascular malformations, over the past years, we have seen patients with symptomatic DVAs. Therefore, we performed
a retrospective study and a literature study to review how, when, and why DVAs can become clinically significant.
Methods—Charts and angiographic films of 17 patients with DVAs whose 18 vascular symptoms could be attributed to
a DVA were selected from a neurovascular databank of our hospital. MRI had to be available to rule out any other
associated disease. In the literature, 51 cases of well-documented symptomatic DVAs were found. Pathomechanisms
were divided into mechanical and flow-related causes.
Results—Mechanical (obstructive or compressive) pathomechanisms accounted for 14 of 69 symptomatic patients
resulting in hydrocephalus or nerve compression syndromes. Flow-related pathomechanisms (49 of 69 patients)
could be subdivided into complications resulting from an increase of flow into the DVA (owing to an arteriovenous
shunt using the DVA as the drainage route; n⫽19) or a decrease of outflow (n⫽26) or a remote shunt with
increased venous pressure (n⫽4) leading to symptoms of venous congestion. In 6 cases, no specific pathomechanisms were detected.
Conclusions—Although DVAs should be considered benign, under rare circumstances, they can be symptomatic. DVAs,
as extreme variations of normal venous drainage, may represent a more fragile venous drainage system that can be more
easily affected by in- and outflow alterations. The integrity of the DVA needs to be preserved irrespective of the
treatment that should be tailored to the specific pathomechanism. (Stroke. 2008;39:3201-3215.)
Key Words: arteriovenous shunting 䡲 compression 䡲 developmental venous anomaly 䡲 DVA 䡲 flow imbalance
䡲 hemorrhage 䡲 thrombosis 䡲 venous congestion
D
evelopmental venous anomalies (DVAs), that have been
previously called venous angiomas, are extreme variations of normal transmedullary veins that are necessary for
the drainage of white and gray matter.1,2 They consist of
converging dilated medullary veins that drain centripetally
and radially into a transcerebral collector that opens either
into the superficial subcortical or deep pial veins.3,4 The
DVAs have no proliferative potential, no direct arteriovenous
shunts, and normal brain parenchyma between the dilated
veins.5 DVAs serve as normal drainage routes of the brain
tissue because the habitual venous drainage of their territory
is absent. Their etiology and mechanism of development are
unknown, but it is currently accepted that they act like a
compensatory system of cerebral parenchyma venous drainage due to early failure, abnormal development, or an
intrauterine occlusion of normal capillaries or small transcerebral veins.2
DVAs are benign anatomic variations and are, therefore,
usually incidentally discovered. Although in the past, different
clinical symptoms were attributed to be caused by DVAs, MRI
has changed the understanding of DVAs’ natural history and
associated clinical symptoms; most hemorrhages are related to
associated cavernomas rather than to the DVA,6 epilepsies are
due to associated cortical dysplasias,7 and pseudotumoral effects
can be secondary to associated lymphatic malformations.8
Although it is thus generally accepted that DVAs are only
rarely symptomatic, their exact clinical significance still
remains controversial. Most series described the epidemiology, distribution, radiological characteristics, and associated
conditions of DVAs. However, these studies did not differentiate whether symptoms arose from the DVA itself or rather
from pathologies associated with the DVA (ie, cavernomas).
The aim of this article is to describe, by the aid of a
Received April 9, 2008; final revision received May 9, 2008; accepted May 20, 2008.
From the Service de Neuroradiologie Diagnostique et Thérapeutique (V.M.P., S.G., T.K., T.A., A.O., F.T., P.L.L.), Hôpital de Bicêtre, Le
Kremlin-Bicêtre, Paris, France; the Department of Radiology (S.G., S.P.), Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; and the
Department of Neuroradiology (T.K.), University Hospital Aachen, Aachen, Germany; and the Division of Neuroradiology, Department of Medical
Imaging (T.K.), Toronto Western Hospital, Toronto, Canada.
Correspondence to Timo Krings, MD, PhD, Division of Neuroradiology, Department of Medical Imaging, Toronto Western Hospital, McLaughlin
Pavilion, 3rd Floor, 399 Bathurst St., Toronto, ON, Canada M5T 2S8. E-mail [email protected]
© 2008 American Heart Association, Inc.
Stroke is available at http://stroke.ahajournals.org
DOI: 10.1161/STROKEAHA.108.521799
3201
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Stroke
Table 1.
Own Series of 17 Patients With 18 Episodes of Vascular Complications Attributable to a DVA
Patient Number
December 2008
Age
Sex
Mechanism of Complication
Morphological Presentation
Clinical Symptoms
Topography
1
1 year
F
Mechanical
Right proptosis
Proptosis and eye
pain
Left temporal
2
20/24 years
M
1998—mechanical
1998—obstructive hydrocephalus
1998—headaches
Bilateral
cerebellum
2002—flow misbalance with outflow
obstruction
2002—hemorrhage
2002—vertigo,
ataxia
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3
1 month
M
Flow misbalance with outflow
obstruction
Hemorrhagic venous infarction
Seizures at birth
Left temporal
4
32 years
F
Flow misbalance with outflow
obstruction
Venous congestion
Headache,
Parinaud
syndrome
Mesencephalon/
cerebellum
5
8 months
F
Flow misbalance with outflow
obstruction
Hemorrhagic venous infarction
and SAH
Headache,
seizures
Left temporal
6
11 months
F
Flow misbalance with outflow
obstruction
SAH
Syncope and
seizures
Right deep nuclei
7
5 years
F
Flow misbalance with outflow
obstruction
Venous infarction
Seizures and left
hemiparesis
Right temporal
8
29 years
M
Flow misbalance with outflow
obstruction
Venous congestion
Headache,
somnolence,
aphasia
Left frontal
9
58 years
F
Flow misbalance with outflow
obstruction
Venous congestion
Headache, right
hemiparesis
Left deep ganglia
10
41 years
M
Flow misbalance with outflow
restriction due to remote shunt
Hemorrhage
Headache,
vomiting
Right temporal
11
9 years
M
Flow misbalance with increased
inflow due to microshunt
Hemorrhage
Headache and
seizures
Left temporal
12
14 years
F
Flow misbalance with increased
inflow due to microshunt
Multiple cerebellar hemorrhages
(1999, 2002, 2004, 2007)
Headaches,
ataxia,
hydrocephalus
Bilateral
cerebellum
13
24 years
M
Flow misbalance with increased
inflow due to microshunt
Hemorrhage
Headache, left
hemiparesis
Right frontal
14
8 years
M
Flow misbalance with increased
inflow due to microshunt
Hemorrhage
Ataxia and
somnolence
Right cerebellar
hemisphere
15
2 days
F
Spontaneous/idiopathic
Hemorrhage
Seizures
Left frontal
16
32 years
F
Spontaneous/idiopathic
Hemorrhage
Headache
Left basal ganglia
17
42 years
F
Spontaneous/idiopathic
Venous infarction
Right hemiparesis
Right hemiparesis
Left deep ganglia
(Continued)
retrospective series of cases and a review of the literature
(after MRI has been introduced), how and when DVAs can
become clinically significant. In all our patients and the cases
from the literature, we systematically looked for the cause of
the complication of the DVA. More specifically, we studied
the relation of the DVA to neighboring structures and we
analyzed the balance of the in- and outflow of the DVA.
Therefore, we aimed at reviewing all possible pathomechanisms and describe potential therapeutic options.
Methods
Patients were selected after a retrospective search through the
databank of our hospital into which, since 1989, patients were
prospectively entered. To date (May 2007), there is a total of 4217
patients of which 80 patients were found whose principal diagnosis
was “DVA.” Within those, 17 patients presenting with 18 direct
vascular complication or a neurological symptom related directly to
the region of the brain that is drained by the DVAs and its anatomic
structure, diagnosed by angio-CT, MRI, and confirmed by digital
angiography, were included in this series. We analyzed epidemio-
Pereira et al
Table 1.
Symptomatic Developmental Venous Anomalies
3203
Continued
Risk Factors/Associated
Conditions
Scan/MRI
Angioarchitecture/Venous Drainage
Focal atropy
Bihemispheric and complex 3 frontal v. 3 ophthalmic v.
1998—hydrocephalus
Large and complex
2002—venous congestion
Bilateral cerebellum 3 left precentral cerebellar v. 3 VG
Congestive edema surrounding
the venous collector
thalamostriate v. 3 ICV 3 subependymal collector 3 VG
Conservative
Stenosis of venous collector/blue
rubber bleb nevus syndrome
Large and complex
Treatment/Follow-Up
1998—III ventriculostomy
2002—Conservative
Stenosis of venous collector,
venous ectasia
Conservative/normal
development
Subtemporal v. 3 atrial v. 3 subependymal collector
3 VG
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Venous congestion, edema in
the DVA territory
Complex and large
bilateral cerebellum 3 precentral cerebellar v. 3 VG
Thrombosis of venous collector
(precentral cerebellar v.)
Conservative/spontaneous
recovery
Venous infarction
Complex
Thrombosis of venous collector
Conservative/good
recovery with normal
development
Left temporal 3 atrial v. 3 basal v. 3 VG
Partial thrombosis of DVA
collector
Right deep nuclei 3 ICV 3 internal parietal v. 3 SSS
Stenosis of venous collector
Conservative /no
follow-up
Venous infarction
Right temporal 3 subtemporal v. 3 epidural sinus 3
transverse sinus
Thrombosis of venous collector
Conservative/good
recovery
Cytotoxic and vasogenic
edema
Frontopolar v. 3 SSS
Stenosis and thrombosis of
venous collector
Anticoagulation/good
recovery
Vasogenic and cytotoxic
edema
Left basal ganglia 3 inferior striate v. 3 basal v.
Stenosis venous collector
Anticoagulation/good
recovery
Right temporal
intraparenchymal hematoma
Right temporal 3 subependymal v. 3 inferior temporal
v. 3 䡠 䡠 䡠
Complex with capillary ectasia and tortuous and dilated
medullary veins close to fistula/left temporal 3
transinsular collector 3 Labbé v. and atrial v. 3 lateral
atrial v. 3 basal v.
Left frontal AVM
AVM embolization/good
recovery
Pseudoaneurysm—medullary
microshunts
Arterial embolization/good
recovery
Ventricular hemorrhage/large
medullary zone
Left cerebellum hematoma
Large with capillary ectasia and tortuous and dilated
medullary veins close to fistula/bilateral cerebellum 3
basal v.3 VG
Microshunts
Arterial embolization/good
recovery
Frontal intraparenchymal
hematoma
Right paracentral lobule 3 venous collector 3 SSS
Microshunts
Arterial embolization/good
recovery
Intraparenchymal cerebellar
hematoma
Right cerebellar hemisphere 3 Lateromesencephalic v. 3
precentral cerebellar v. 3 VG
Microshunts
Arterial embolization/good
recovery
Left frontal hematoma
Left frontal 3 pericallosal v. 3 frontal v. 3 SSS
Normal
Conservative/good
recovery, normal
development
Left basal hematoma
Large with capillary ectasia
Normal
Conservative/good
recovery
Vasogenic edema
Left basal ganglia 3 inferior striate v. 3 basal v.
Normal
Conservative/no follow-up
Left basal ganglia 3 inferior striate v. 3 basal v.
F indicates female; M, male; SAH, subarachnoid hemorrhage; v., vein; VG, vein of Galen; ICV, internal cerebral vein; SSS, superior sagittal sinus.
logical variables like age, gender, associated risk factors as well as
clinical presentation, radiological data, treatments options, and
follow-up. Considering the angioarchitecture of the DVA, we examined size, topography, venous drainage, morphology of medullary
veins and venous collector, presence or absence of capillary ectasia,
and medullary blush or associated pathology (increased vascular
transit time through the DVA, associated cerebral arteriovenous
malformations (AVMs) or dural arteriovenous shunts remote or close
to the DVA).
We restricted this review to complications considered to be
directly related to DVAs to recognize under which conditions
they could become symptomatic. The following exclusion criteria
were therefore chosen: (1) unspecific symptoms like headaches or
longstanding symptoms such as epilepsy were not considered if
there was no MR evidence of a causative link to the DVA (such
as congestive edema in the immediate vicinity);7,9 –14 (2) MRI
abnormalities without symptoms (T2* hypointensities, T2/flair
hyperintensity), although related to DVAs, were not included;5,15,16 (3) patients with DVAs and symptomatic cavernomas
because of their established natural history (hemorrhage, epilepsy, mass effect);3,14,17–24 and (4) patients and series25,26 presenting incomplete radiological or clinical data necessary to
3204
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December 2008
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Figure 1. Pathomechanisms of symptomatic DVAs. Based on imaging findings and clinical symptoms, two major pathomechanisms
could be identified: mechanical and flow-related. Patients in whom neither pathomechanism was observed were grouped separately as
idiopathic or spontaneous. Although mechanical complications lead either to hydrocephalus or to vessel–nerve conflicts, flow-related
mechanisms could be further subdivided into those that were related to an increase in inflow into the DVA or to an obstruction of the
outflow.
exclude completely an associated disease (eg, patients investigated or manuscripts before the MRI era).
In addition, we reviewed all manuscripts from 1980 to 2007 in the
Medline, Embase, and Scopus databases using the following search
terms: “venous angioma,” “developmental venous anomaly,” “venous malformation,” “medullary malformation,” and “medullary
venous malformation.” The selection and exclusion criteria described previously were the same for the series of patients selected
from our databank as for the literature review.
Results
In our databank, we found 80 cases with the principal
diagnosis of “DVA.” Of those, there were 17 cases with 18
vascular complications directly linked to the DVA and that
could not be associated with other pathologies (Table 1 ). One
patient (Case 2) had 2 separate complications from his DVA.
Within the literature, 51 cases were found that fulfilled our
criteria of well-documented truly symptomatic DVAs and in
whom MRI was available to rule out any other associated
disease. We restrict our review of the literature and the case
series to these 68 patients with 69 distinct clinical presentations owing to vascular complications of the DVA. Values of
incidence and prevalence of symptomatic DVAs could not be
given, because data from our center are likely to be biased by
referral. Based on the imaging features and clinical symptoms, 2 major groups of presumed pathophysiological mechanisms could be identified: mechanical and flow-related.
Patients in whom complications were present and in whom no
pathomechanism could be identified were grouped separately
(idiopathic pathomechanism; Figure 1).
patients from our series and 12 additional cases from the
literature (Table 2).
The mean age of patients in this group was 30 years with
a range from 1 to 62 years; there was no gender predominance
(male:female⫽7:7). Most cases were related to the collecting
vein of a posterior fossa DVA (n⫽9 [64.3%]); in 42.8% of
cases, the venous collector of the DVA was dilated. There
was no relation between compressive symptoms and the size
of the drained medullary zone. A detailed description of the
clinical symptoms can be seen in Tables 1 and 2. In brief,
obstructive hydrocephalus (n⫽7 [50%]) and neurovascular
nerve compression syndromes (n⫽6 [42.8%]), being trigeminal neuralgia, facial hemispasm, or tinnitus, were the most
common findings. The structure most typically compressed
was the mesencephalic aqueduct (n⫽6 [42.8%]) followed by
the trigeminal nerve (n⫽3 [21.4%]) and the acousticofacial
complex (n⫽3 [21.4%]). The orbital contents (Case 1) and
the interventricular foramen were compressed in one patient
each.
The patients presenting with hydrocephalus had the occlusion at the level of the aqueduct (n⫽6) or, in a single case,4
at the level of the interventricular foramen producing unilateral ventricular dilatation. Shunting surgery was performed in
3 patients,27,28 endoscopic third ventriculostomy in 2 (Case 2
and29), whereas 3 patients (28%) were kept under close
clinical observation without published surgical treatment.30,31
Three patients with nerve compression underwent decompressive treatment with excellent results32–34 (Figure 2). For
the remaining patients, the treatment was conservative.
Mechanical
Mechanical complications were considered when some component of the DVA (typically the draining collector vein)
compressed an intracranial structure (parenchyma, cranial
nerves, ventricles, or bone), thereby producing compressive
symptoms that could be documented by imaging. We found 2
Flow-Related
Flow-related complications were characterized as a misbalance of the in- and outflow of blood in the DVA system
raising the pressure in the DVA either due to an increased
inflow or a restricted outflow and were present in 49 patients.
Pereira et al
Table 2.
Symptomatic Developmental Venous Anomalies
3205
Findings in All Patients Reported in the Literature With ‘Mechanical’ Complications Related to the DVA
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Reference
Morphology
Age,
Years
Sex
Clinical Presentation
Localization
Angiography/Imaging
Drainage of Venous
Collector
Treatment/
Follow-Up
Watanabe,
199128
Hydrocephalus
39
M
Progressive
headaches, vomiting
Vermis
cerebellum
Dilated subependymal
venous collector with
aqueductal
compression
Precentral cerebellar
v.
Ventricular
shunt/Good
recovery
Truwit,
19924
Unilateral
ventricular
dilatation
37
F
Headaches
Left basal ganglia
and thalamus
Dilated venous
collector with
compression of
interventricular
foramen
Left striate v. 3
ICV
Not reported
Oka,
199329
Hydrocephalus
43
F
Headaches and
seizures
Tectum
Dilated
transmesencephalic
venous collector with
aqueductal
obstruction
Precentral cerebellar
v. 3 VG
Endoscopic III
ventriculostomy
Nagata,
199534
Vessel–nerve
contact
35
M
Left trigeminal
neuralgia
Left cerebellar
hemisphere
Large and complex;
dilated venous
collector with
compression of CN V
Left petrosal v.
Decompressive
surgery
Blackmore,
199630
Hydrocephalus
16
F
Intermittent throbbing
occipital headache,
associated with
photophobia and
motion sickness
Left thalamus
Dilated subependymal
venous collector with
aqueductal
compression
VG (direct)
Conservative/clinical
follow-up
unchanged
Chen,
199632
Vessel–nerve
contact
53
F
Left facial
hemispasm
Left cerebellar
hemisphere
Large dilated venous
collector with
compression of CN VII
Precentral cerebellar
v. 3 petrosal v.
Decompressive
surgery/good
recovery
Kuker,
199744
Vessel–nerve
contact
62
M
Left trigeminal
neuralgia and slight
dysesthesia V2
and V3
Lobus semilunaris
superior and
inferior of the left
cerebellar
hemisphere
Transpontine v.
without venous
ectasia, compression
of CN V
v. of the lateral
recess of
the fourth
ventricle 3
subependymal v. 3
VG
Conservative
Korinth,
200233
Vessel–nerve
contact
37
F
Trigeminal neuralgia
Left cerebellar
hemisphere
Large DVA
compressing CN V,
no venous ectasia
Lateral
mesencephalic v.
Decompressive
surgery/good
recovery
Bannur,
200227
Hydrocephalus
11
M
Persistent
headache⫹acute
ataxia, vomiting,
vertigo, papilledema
Midbrain close to
aqueduct
Aqueductal stenosis
by dilated venous
collector
subependymal v. 3
VG
Shunt/good
recovery
Yagmurlu,
200231
Hydrocephalus
7
F
Severe, progressive
headaches
Multiple DVAs
(thalamic,
bilateral
cerebellar)
Signs of compression
of the aqueduct by
dilated venous
collectors
v. of the lateral
recess of the fourth
ventricle 3
subependymal v. 3
VG
Conservative
periaqueductal v.
3
lateromesencephalic
v.
Malinvaud,
200643
Vessel–nerve
contact
55
M
Permanent,
nonpulsatile tinnitus
in right ear
Right cerebellar
hemisphere
Dilated venous
collector,
compressing CN VIII
Precentral cerebellar
v. 3 petrosal v.
Conservative;
clinically unchanged
Shim,
200745
Vessel–nerve
contact
5
M
Progressive hearing
loss
Right cerebellar
hemisphere
Dilated venous
collector,
compressing CN VIII;
associated scalp
hemangiomas
Petrosal v. (direct)
Conservative
M indicates male; F, female; v., vein; CN, cranial nerve; ICV, internal cerebral vein; VG, vein of Galen.
3206
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December 2008
Figure 2. DVA causing mechanical compression. The patient had severe trigeminal pain in the distribution of left V2 and
V3. A (contrast-enhanced T1-weighted
axial section), the enlarged venous collector of a transpontine DVA encroaches on
the trigeminal nerve at its exiting zone
from the brain stem (arrow). B–C, Vertebral artery angiograms in anteroposterior
and lateral views in the venous phase
demonstrate a classical umbrella-shaped
pattern of the DVA with the medullary
vein draining into an enlarged collector
that further drained into the superior
petrosal vein. D–E, Surgical view with
compression of the left trigeminal nerve
(arrow in E). A Teflon patch to separate
the nerve from the vein was placed with
excellent results and complete recovery
from the trigeminal pain immediately after
surgery.
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Increase of Developmental Venous Anomalies’ Inflow
An augmentation of inflow into the DVA was either due to
microshunts into the DVA or AVMs that used the DVA as the
drainage route. We found 4 cases in our databank and 15
cases in the literature with a mean age of 28.5 years ranging
from 1 to 62 years and a discrete male predominance
(male:female⫽12:7; Table 3). The initial clinical presentations included headaches (n⫽11 [61%]), neurological deficits
(n⫽7 [38%]), seizures (n⫽4 [22.2%]), and coma (n⫽4
[22.2%]). The morphological presentation was mainly hemorrhages in 12 cases (66.6%), including intraparenchymal
(n⫽8 [66%]), intraventricular (n⫽2 [17%]), and both (n⫽2
[17%]). The remaining 6 cases (33.3%) had venous infarction
in the drainage territory of the DVA, presumably due to
venous congestion after arterialization. Thirteen lesions
(72%) were located supratentorially and 6 lesions (28%)
infratentorially. The angioarchitectural aspects were microshunts into capillary veins at the medullary zone of the DVA
(n⫽11 [55%]; Figures 3 and 4) and typical nidal-type AVMs
draining through the venous collector (n⫽8 [45%]). Among
them, only 3 cases were larger than 5 cm and had complex
venous drainage with no relationship with the clinical manifestation. Asymmetrical dilatation of the capillary veins in the
medullary zone of the DVA of the patients with microshunts
was observed in 76% (8 of 11). This finding helped to support
the diagnosis in some cases, which was subsequently confirmed by superselective injections.
Treatment strategies were extremely variable according to
architecture, morphological presentation, and the treating
center. Radiosurgery was the most frequent option (n⫽7
[38.8%]), even for hemorrhagic or ischemic presentations,
and was focused on the AVM and DVA (70%) or on the
AVM alone (30%). Five patients (including all 4 cases from
our series) were treated with endovascular embolization of
the lesion (microshunt or AVM) with careful preservation of
the patency of the DVA using transarterial glue (n-butyl
cyanoacrylate, Histoacryl; B. Brain, Melsungen, Germany)
injections. All patients recovered from their bleeding without
new neurological deficits.
Among the 13 patients who presented with hemorrhage, 3
patients had their hematoma surgically drained preserving the
DVA itself. Two other patients with an associated AVM were
operated with the goal of AVM resection. In one of them, the
DVA was occluded unintentionally and the patient had severe
venous ischemia resulting in new and permanent neurological
deficits.
Developmental Venous Anomaly Outflow Restriction
An imbalance of blood flow can also occur if the venous
outlets of the DVA are restricted while the inflow is normal.
This category can be further subdivided into anatomic and
functional causes, the latter being due to a remote arterial
overload to the venous system due to a distant shunt/AVM,
whereas the former can be secondary to thrombosis of the
DVA channels, stenosis or occlusion of the venous collector,
or the distal draining sinus.
Anatomic Obstacle
Concerning mechanical obstruction of DVA outflow, we
report 8 cases from our databank and 18 previously published
cases (Table 4). The mean age was 32.1 years with no gender
predominance (male:female⫽14:12). There were 7 patients
(27.6%) who presented with hemorrhage (either intraparenchymal or subarachnoid), whereas the major presentation was
venous congestion with edema (Figure 5). Clinical symptoms
consisted of neurological deficits (n⫽20 [68.9%]), headaches
(n⫽17 [58.6%]), seizures (n⫽12 [41.3%]), and alteration of
consciousness or altered mental status (n⫽6 [20.7%]).
Twenty-three (79.3%) were located supratentorially. No difference in size (only 55% were larger than 3 cm) nor venous
drainage (55% draining to the deep venous system and 45%
to the superficial veins) was found within this group of
patients. Fifteen (51.7%) had thrombosis on the venous
collector, 24.1% (n⫽7) had stenosis at some point of the
DVAs drainage (Figure 5), 13.8% (n⫽4) had complete
thrombosis of the DVA with a systemic procoagulating factor
or state (ie, puerperium), and 10.4% (n⫽3) had complete
thrombosis without an identifiable cause. This mechanical
obstruction lead to venous congestion resulting in hemorrhagic or venous infarction in all symptomatic patients, which
Pereira et al
Table 3.
Reference
Symptomatic Developmental Venous Anomalies
Findings in All Patients Reported in the Literature With Increased Inflow Into the DVA
Age,
Years
Sex
35
F
Clinical
Presentation
Mechanism
Morphology
Flow misbalance:
increased inflow
(microshunt)
Parenchymal
hemorrhage
Bergui, 199759
Flow misbalance:
Increased inflow
(microshunt)
Parenchymal
hemorrhage
39
M
Headache,
aphasia, right
hemiparesis
Left
temporoinsular
Komiyama,
199949
Flow misbalance:
increased inflow
(microshunt)
Intraventricular
hemorrhage
22
M
Headache,
dizziness
Left parietal
Truwit, 19924
Flow misbalance:
increased inflow
(AVM)
Intraparenchymal
hemorrhage
1
M
Seizures
Left frontal
Awad, 199347
Flow misbalance:
increased inflow
(microshunt)
Intraparenchymal
hemorrhage
54
M
Seizures,
headache
Awad, 199347
Flow misbalance:
increased inflow
(microshunt)
Intraparenchymal
hemorrhage
39
F
Awad, 199347
Flow misbalance:
increased inflow
(microshunt)
Venous
congestion
36
Lindquist,
199360
Flow misbalance:
increased inflow
(AVM)
Intraparenchymal
hemorrhage
Lindquist,
199360
Flow misbalance:
increased inflow
(AVM)
Meyer, 199550
Nussbaum,
199861
Bergui, 199759
3207
Risk
Factor/
Associated
Conditions
Treatment/
Follow-Up
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Localization
Angiography
Venous Drainage
Brainstem
Capillary ectasia;
v. of the lateral
recess of the fourth
ventricle 3
precentral cerebellar
v. 3 VG
Medullary
microshunts
Conservative/good
recovery
Classical aspect
without capillary
ectasia
Inferior striate v. 3
basal v.
Medullary
microshunts
Radiosurgery/partial
recovery
Venous ectasia;
SSS (direct)
Medullary
microshunts
Conservative/good
recovery
Classical pattern
without capillary
ectasia
SSS (direct)
AVM draining
directly into
DVA
Surgery with
resection of the
AVM/good recovery
Right temporal
Not reported
Not reported
Medullary
microshunts
Surgery with
drainage of
hematoma/good
recovery
Seizures
Right frontal
Not reported
Not reported
Medullary
microshunts
Surgery (drainage
of hematoma)/good
recovery
F
Coma
Left parietal
Not reported
Not reported
Medullary
microshunts
Radiosurgery/good
recovery
60
F
Not reported
Right temporal
Not reported
Not reported
AVM draining
directly into
DVA
Radiosurgery
(DVA/AVM)
Intraparenchymal
hemorrhage
20
M
Not reported
Bilateral
cerebellum
Not reported
Not reported
AVM draining
directly into
DVA
Radiosurgery
(DVA/AVM)
Flow misbalance:
increased inflow
(AVM)
Intraparenchymal
hemorrhage
32
F
Headache,
aphasia, right
hemiparesis and
progressive to
coma
Right parietal
Not reported
SSS (direct)
AVM draining
directly into
DVA
Surgery for AVM
with in advertent
DVA
obliteration/recovery
with severe deficits
Flow misbalance:
increased inflow
(microshunt)
Venous
congestion
24
M
2 episodes of
acute headache,
vertigo,
longstanding
blurred vision
and nystagmus
Right cerebellum
Large
v. of the lateral
recess of the fourth
ventricle 3
precentral cerebellar
v. 3 VG
Medullary
microshunts
Endovascular
arterial glue
embolization/good
recovery
Diplopia,
hemiparesis
tortuous and dilated
medullary veins close
to shunt
asymmetric
opacification, tortuous
and dilated medullary
veins
multiple microshunts;
asymmetric medullary
veins, tortuous and
dilated close to
microshunts
Kurita, 199948
Flow misbalance:
increased inflow
(AVM)
Venous infarction
39
M
Transient
dysarthria
Right temporal
Not reported
Superficial sylvian v.
3 sphenoparietal
sinus
AVM draining
directly into
DVA
Radiosurgery/good
recovery
Yanaka,
200162
Flow misbalance:
increased inflow
(AVM)
Venous
congestion
37
F
Loss of
consciousness
Right basal
ganglia and
lateral wall of
right ventricle
Significant dilatation
of medullary veins
Superior striate v.
3 longitudinal
caudate v.3 lateral
subependymal v. 3
VG
AVM draining
directly into
DVA
Radiosurgery/good
recovery
Aksoy, 200063
Flow misbalance:
increased inflow
(AVM)
Venous
congestion
11
M
Temporal lobe
seizures
Right temporal
lobe
Capillary ectasia
anterior temporal v.
3 basal v.
AVM draining
into 2 DVAs
Radiosurgery for
AVM/good recovery
Koc, 200764
Flow misbalance:
increased inflow
(microshunt)
Intraparenchymal
hemorrhage
56
M
Aphasia, right
hemiparesis
Left temporal
Large;
Not reported
Medullary
microshunts
Drainage of
hematoma
F indicates female; M, male; v., vein; VG, vein of Galen; SSS, superior sagittal sinus.
asymmetric medullary
veins, tortuous and
dilated close to the
hematoma
3208
Stroke
December 2008
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Figure 3. Flow-related complication of a
DVA due to a microshunt into the DVA. This
25-year-old man experienced a sudden
onset of left hemiparesis associated with
severe headaches. A (axial nonenhanced
coronal CT), a right frontoparietal atypical
hemorrhage. B (contrast-enhanced
T1-weighted MRI), the venous collector of a
DVA lateral to the hematoma. Within the
hematoma, medullary vessels are demonstrated as small enhancing areas. C–D
(3-dimensional reconstruction of a right
internal carotid artery angiography, including blowup in D), the communication of a
branch of the pericallosal artery with the
DVA (arrow). In the lateral view of the late
arterial phase (E and blowup in G), the
microshunt can be demonstrated at the
level of the dorsal medullary zone (arrow).
Transarterial embolization with glue was
carried out (F) that resulted in complete
obliteration of the microshunt and preservation of the DVA (H).
corresponded to the DVA drainage territory in 21 cases
(72.4%).
The management was variable due to delay of the diagnosis in most of the patients. There were 16 patients (55.2%)
who received conservative treatment without anticoagulation
and antiaggregation. Systemic heparinization was administered in 9 patients (31%), similar to the treatment in cortical
venous thrombosis. In 3 cases, decompressive craniectomy
for refractory and malignant regional edema was deemed
necessary and in one patient, a ventricular shunt for hydrocephalus treatment due to posterior fossa hypertension after
cerebellar infarction was placed. The overall outcome was
good in 24 patients (82.8%).
Functional Outflow Restriction:
Functional impairment of the venous drainage of the DVA
was suspected in patients with a remote arteriovenous shunt
not draining directly into the DVA but competing and
hindering the normal DVA drainage due to venous hypertension (Figure 6). Although 3 such cases are present in the
literature (2 dural arteriovenous shunts and one pial AVM),
we report one additional patient with a pial AVM distant to
the DVA but likely to produce venous hypertension. The
mean age was 37 years old and all 4 patients were male. All
patients became symptomatic due to venous congestion of the
area drained by the DVA either with hemorrhagic venous
infarction or congestive edema. Management included treatment of the primary shunt to decrease the venous hypertension in 2 cases, whereas in one patient, conservative management with anticoagulation therapy was performed. The
follow-up was uneventful and the patients had a good
recovery.
Idiopathic
Idiopathic complications were attributed to symptomatic cases
with no obvious vascular modification attributable to the DVA,
Figure 4. Flow-related complication of a
DVA due to a microshunt into the DVA.
This 9-year-old boy presented with his
first-ever seizure that was preceded by
severe headaches. A (axial T2*-weighted
MRI), a hematoma in the right forceps
major. B–C, left internal carotid artery
angiography in lateral view in the arterial
(B) and venous phase (C) demonstrate a
large temporooccipital DVA draining
superficially into the vein of Labbé. There
is contrast stagnation in the medullary
zone of the DVA. D–E, after injection into
the left vertebral artery (anteroposterior
view, in arterial phase, D; capillary phase,
E) demonstrate a false aneurysm (arrow)
as the point of rupture of a microshunt
into the DVA. The gluecast (F) penetrates
through the lateral posterior choroidal
branch into the pseudoaneurysm and the
early part of the venous drainage of the
microshunt.
Pereira et al
Table 4.
3209
Findings in All Patients Reported in the Literature With Decreased Outflow From the DVA
Age,
Years
Sex
Venous
infarction
37
F
Flow misbalance:
outflow
obstruction
Venous
infarction
26
Truwit, 19924
Flow misbalance:
outflow
obstruction
Venous
infarction
Field and
Russell, 199567
Flow misbalance:
outflow
obstruction
Kim, 199668
Reference
Symptomatic Developmental Venous Anomalies
Mechanism
Morphology
Bouchacourt,
198665
Flow misbalance:
outflow
obstruction
Yamamoto,
198966
Clinical
Presentation
Drainage of the
Venous Collector
Risk
Factors/
Associated
Conditions
Treatment/
Follow-Up
Downloaded from http://stroke.ahajournals.org/ by guest on June 14, 2017
Localization
Angiography/Imaging
Headache,
seizures, right
hemiparesis
Left frontal
Thrombosis of
venous collector of
DVA
Thalamostriate v. 3
ICV
䡠䡠䡠
Heparin/good
recovery
F
Headache, left
hemiparesis
Right parietal
Large DVA,
thrombosis of
superior sagittal
sinus (SSS)
SSS (direct)
Postpartum
Decompressive
craniotomy/recovery
with mild residual
symptoms
12
M
Seizures
Left frontal
Large, complex DVA
with stenosis of
venous collector
SSS (direct)
䡠䡠䡠
Conservative/no
follow-up
Congestive
hemorrhage
34
F
Persistent
headache, left
hemianopsia
Right
parietotemporal
Thrombosis of
venous collector of
DVA
Tentorial venous
plexus 3 sup.
petrosal sinus
䡠䡠䡠
Conservative/good
recovery
Flow misbalance:
outflow
obstruction
Venous
infarction
13
M
Ataxic gait,
emesis, left
hemiparesis,
right mydriasis
Right
temporoparietal
Large, complex DVA
with thrombosis of
venous collector
Labbé 3 transverse
sinus
Paucity of
alternate
superficial
venous
drainage
pathways
Decompressive
craniotomy/death
Guerrero,
199869
Flow misbalance:
outflow
obstruction
Venous
infarction
62
M
Vertigo, diplopia,
ataxia and
occipital
headache⫹
hydrocephalus
Mesencephalon⫹
right cerebellar
hemisphere
Large DVA with
thrombosis of venous
collector
Precentral cerebellar
v. 3 VG
䡠䡠䡠
Conservative/slow
recovery
Merten et al,
199854
Flow misbalance:
outflow
obstruction
Congestive
hemorrhage
50
F
Headache,
aphasia, right
hemiparesis
Left basal ganglia
Large collector
significant dilatation
of medullary veins;
thrombosis of venous
collector
Subependymal v. 3
Sylvian v.
䡠䡠䡠
Heparin followed by
warfarin/good
recovery
Konan, 199970
Flow misbalance:
outflow
obstruction
Venous
infarction
31
M
Severe
headache,
vomiting, ataxia,
and right-sided
facial paresis
and coma
Bilateral
cerebellar
Large DVA, presence
of a clot inside the
DVA collector
Precentral cerebellar
v. 3 VG
Right-sided
lower midbrain
cavernous
angioma
Conservative/mild
residual cerebellar
symptoms
Herbreteau,
199971
Flow misbalance:
outflow
obstruction
Venous
infarction
45
M
Seizures
Left parietal
Venous collector
stenosis
Thalamostriate v. 3
ICV
䡠䡠䡠
Conservative/good
recovery
Lai et al,
199972
Flow misbalance:
outflow
obstruction
Venous
infarction
56
F
Seizures, left
hemiparesis
Right parietal
Thrombosis of
venous collector
SSS (direct)
䡠䡠䡠
Conservative/good
recovery
Thobois et al,
199973
Flow misbalance:
outflow
obstruction
Venous
infarction
25
F
Headache,
seizures, and
left hemianopsia
homonym
Right
parieto-occipital
Thrombosis of
venous collector
SSS (direct)
Contraceptives
Anticoagulation/
good recovery
Masson,
200074
Flow misbalance:
outflow
obstruction
Venous
infarction
68
M
Headache,
seizures, right
hemiplegia, and
aphasia
Left frontoparietal
Thrombosis of SSS
SSS (direct)
䡠䡠䡠
Heparin/mild motor
sequelae
Hammoud,
200275
Flow misbalance:
outflow
obstruction
Venous
infarction
26
F
Right-sided
acute numbness
and weakness
Left frontoparietal
Thrombosis of
venous collector
SSS (direct)
Postpartum/
family history
of
thrombosis/
smoke/
contraceptives
Conservative/good
recovery
LovrencicHuzjan, 200456
Flow misbalance:
outflow
obstruction
Subarachnoid
hemorrhage
39
M
Occipital
headache,
nausea and
vomiting.
Cerebellum/SAH
Thrombosis of
venous collector
Precentral cerebellar
v. 3 VG
䡠䡠䡠
Conservative/good
recovery
Peltier, 200476
Flow misbalance:
outflow
obstruction
Venous
infarction,
subsequent
obstructive
hydrocephalus
32
M
Headache,
vomiting, and
coma
Pons/left
cerebellar
hemisphere
Complex, large DVA,
thrombosis of venous
collector
v. of the lateral
recess of the fourth
ventricle
3 petrosal v.
䡠䡠䡠
External
drainage/recovery
with mild deficits
(Continued)
3210
Stroke
Table 4.
Continued
December 2008
Risk
Factors/
Associated
Conditions
Age,
Years
Sex
Clinical
Presentation
Localization
Angiography/Imaging
Ischemic—
venous
congestion
49
M
Seizures
Left frontal
Thrombosis of
venous collector
SSS (direct)
Elevated factor
VIII activity of
227%
Anticoagulation/
good recovery
Flow misbalance:
outflow
obstruction
Venous
infarction
9
F
Right
hemiparesis
Left parietal
Thrombosis of
venous collector
SSS (direct)
Homozygous
for 4G allele
of PAI-1
Heparin/slow
recovery
Seki, 200778
Flow misbalance:
outflow
obstruction
Congestive
hemorrhage
33
M
Headache, right
hemiparesis,
and coma
Left
temporoparietal
Ectasia and
thrombosis of venous
collector
VG (direct) 3
straight sinus
Straight sinus
stenosis
Craniectomy,
hematoma
drainage/recovery
with mild deficits
Kuncz, 200157
Flow misbalance:
outflow
restriction due to
remote shunt
Venous
infarction
31
M
Seizures and
right
hemiparesis
Left frontal
Concurrence of
venous drainage with
DAVFs and slow flow
in DVA
SSS (direct)
Distant
bilateral
DAVFs from
ethmoidal
arteries,
draining into
SSS
Surgery for
DAVFs/left frontal
atrophy and
cognitive deficits
Agazzi, 200153
Flow misbalance:
outflow
restriction due to
remote shunt
Venous
infarction
39
M
Seizures, mild
left hemiparesis,
homonymous
left hemianopsia
(1) Right basal
ganglia; (2) right
temporal
Two DVAs, one of
which had
microshunts and
early drainage;
tortuous and dilated
medullary veins close
to fistula
(1) Subependymal v.
3 tentorial sinus;
(2)
Restricted
venous
drainage due
to anatomic
variations
Aspirin/good
recovery
Complex DVA,
concurrence of
venous DVA drainage
with DAVF and slow
flow in DVA
v. of the lateral
recess of the fourth
ventricle 3
precentral cerebellar
v. 3 VG
Right posterior
fossa
Conservative/stable
Reference
Mechanism
Morphology
Flacke, 200677
Flow misbalance:
outflow
obstruction
Vieira Santos,
200655
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Dudeck, 200479
Flow misbalance:
outflow
restriction due to
remote shunt
Venous
congestion
16
M
Pulsatile tinnitus
14 months after
posterior fossa
surgery for brain
stem cavernoma
resection
Right cerebellar
hemisphere
Drainage of the
Venous Collector
inferior temporal v.
3 Labbé
Treatment/
Follow-Up
DAVF (Cognard
type IIa⫹b),
fed by
ipsilateral
cerebellar
arteries
F indicates female; M, male; SAH, subarachnoid hemorrhage; DAVF, dural arteriovenous fistula; v., vein; ICV, internal cerebral vein; VG, vein of Galen.
no associated vascular condition nor systemic factor. We report
3 cases of our series and 3 previously reported cases in this
category presenting with hemorrhage in 4 and venous infarction
in 2. The global mean age was 33.5 years old (range, 0 to 56
years); all cases had neurological deficits. Three patients had
unusually large and complex DVAs with deep venous drainage
in 2 patients. Because no risk factor could be found, there was no
treatment considered in these cases (Table 5).
Discussion
The presumed origin of DVAs is considered to be venous
thrombosis35 during Padget’s fourth to seventh stage that
Figure 5. Flow-related complication due
to an anatomic outflow restriction: This
58-year-old woman had an acute onset of
right hemiparesis and headaches. A (axial
nonenhanced coronal CT), a hypodensity
of the left basal ganglia region that was
not related to a typical vascular territory.
B–C, CT angiography in axial (B) and
coronal views (C) demonstrate a DVA with
dilated medullary veins draining into
the deep venous system. D–E, the
3-dimensional reconstruction of the
venous phase of a left internal carotid
artery injection demonstrates a basal ganglia DVA draining into the basal vein of
Rosenthal. There is a stenosis of the
venous collector (arrow in D) and a dilatation of the vein proximal to the stenosis
(small arrows in E). Presumably, the stenosis had led to a decreased outflow of
the DVA and venous congestive edema
in the medullary zone normally drained by
the DVA.
Pereira et al
Symptomatic Developmental Venous Anomalies
3211
Figure 6. Flow-related complication due to a functional outflow restriction secondary to a remote shunt. This 51-year-old man had sudden severe onset of headaches followed by a first-ever seizure. A (coronal T2*-weighted sequences), 2 separate areas of bleeding in
the left frontal lobe and the right temporal lobe. B–C, right internal carotid artery angiogram in anteroposterior view in the arterial (B)
and venous phase (C) demonstrates a left frontal nidal type AVM draining into the superior sagittal sinus. There is a right temporal DVA,
the location of which corresponds to the second bleeding draining into the transverse sinus. Marked contrast stagnation within the DVA
was noted (arrow). On follow-up studies, no cavernoma that could have been responsible for the right temporal lobe hemorrhage was
found and the pathomechanism of the bleeding was supposed to be due to the remote shunt that increased the venous pressure and
led to a functional obstruction of the DVA outflow.
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subsequently leads to variations of the normal venous drainage. These variations are either constituted by dilated medullary veins, that converge into a large transcerebral collector,36 or by persistence of intrinsic venous anastomoses37 with
an absence of normal draining veins in the region. In
comparison to normal veins, histologically, DVAs are characterized by a composition of thin-walled vessels spread in
normal neural parenchyma draining into a large caliber vein
with a thicker wall6 without a smooth muscle layer nor elastic
lamina.38
On contrast-enhanced CT, the venous collector of the DVA
is readily detectable as a linear or curvilinear focus of
enhancement, typically coursing from the deep white matter
to a cortical vein or a deep vein or to a dural sinus. On MRIs,
DVAs typically have a transhemispheric flow void on both
T1- and T2-weighted images. After the administration of
gadolinium, because of the slow flow, significant enhancement of the caput medusae of the medullary veins and venous
collector are observed. Digital subtraction angiography is
rarely necessary to diagnose a DVA. Classical angiographic
appearance is that of a caput medusae appearance of transmedullary veins visualized during the early to middle venous
phase, draining into a large venous collector, which can
extend either to the superficial or deep venous system
depending on the type of the DVA.
DVAs are classified as deep (ie, draining into deep subependymal veins and the galenic system) or superficial (ie,
draining into cortical veins). In 70%, the latter pattern is
Table 5.
Findings in All Patients Reported in the Literature With Idiopathic Vascular Complications and DVAs
Localization
Angiography
Venous Drainage
Risk
Factors/Associated
Conditions
Aphasia
Left
frontoparietal
Large typical
pattern
SSS (direct)
None
Conservative/good
recovery
M
Seizures
Right frontal
Large typical
pattern
SSS (direct)
None
Conservative/good
recovery
M
Seizures and
right
hemiplegia
Left parietal
Classical
pattern
SSS (direct)
None
Heparin/good
recovery
Mechanism
Morphology
Age,
Years
Uchino,
199680
Idiopathic
Hemorrhage
49
M
Uchino,
199680
Idiopathic
Venous
infarction
53
Masson,
200074
Idiopathic
Venous
infarction
43
Reference
present, deep drainage is found in 20%, whereas a combination of deep and superficial drainage occurs in 10%.2,39 Apart
from the classical appearance, complex DVAs can have
multiple collectors, drain a large area, and can be associated
with both deep and superficial drainage. In general, DVAs
occur most often in the frontal lobe (36% to 56%) followed
by the parietal (12% to 24%), occipital (4%), and the
temporal lobes (2% to 19%); the cerebellum (14% to 29%);
the basal ganglia (6%); the thalamus, the ventricles (11%);
and the brainstem (less than 5%).2,39
Radiological and autopsy series demonstrated that DVAs
occur in 2.5% to 3% of the population and they are the most
common vascular “malformation” of the central nervous
system constituting approximately 60% of all vascular malformations, whereas capillary telangiectasias represent 20%,
cavernomas 10%, AVMs 9%, and dural arteriovenous shunts
1% in larger autopsy series.24,40 – 42 They have been seen or
diagnosed in patients presenting with symptoms such as
seizures, vertigo, syncope, tinnitus,43 and headaches; however, because these symptoms are among the most often to
lead to MRI investigation, a direct relationship could not be
established and it is currently accepted that they represent an
incidental finding in the vast majority of cases.6
DVAs are considered as stable and benign conditions;
however, as an anatomic variation, they occur in atypical
locations and they may be less flexible to changes of the
intracranial venous equilibrium.2 We classified both our
symptomatic DVAs and those reported in the literature
M indicates male; SSS, superior sagittal sinus.
Sex
Clinical
Presentation
Treatment/
Follow-Up
3212
Stroke
December 2008
according to their presumed pathomechanism and were able
to divide them into 2 subsets: those caused by mechanical
compression of intracranial structures (being due to an
atypical location of the DVA) and those caused by a misbalance of either the in- and outflow in the DVA (therefore being
related to their relative inflexibility of changes in the venous
equilibrium). More than 92.7% of truly symptomatic DVAs
harbored either one of these mechanisms. However, an
important caveat to keep in mind is that it cannot be
completely ruled out that the concurrence of a DVA with
venous thrombosis within its collecting vein could be a mere
coincidence because both entities represent frequent
diseases/variations.
Mechanical-Related Symptomatology
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The venous collector of a DVA can compress intracranial
structures, especially if dilated or ectatic and in close proximity to vulnerable structures. The neurological symptoms
were caused by mechanical compression in 32.7% of all cases
of symptomatic DVAs with hydrocephalus, tinnitus, brainstem deficits, facial hemispasm, and trigeminal neuralgia
being the most common presenting symptoms.4,8,28,30,31,34,44,45
Obstruction of the ventricles has not only been described
for DVAs, but also for dilated drainage veins of an AVM.
Potential sites for obstruction are at the level of the
interventricular foramen (here related to dilated thalamostriate veins) or at the aqueduct (due to a dilated vein of
Galen or transparenchymal venous collectors). These cases
should be differentiated from hydrocephalus secondary to
a hydrovenous imbalance that can be seen in young
patients with high-flow fistulae and vein of Galen
malformations.46
In hydrocephalus related to the venous collector of a DVA,
that cannot be managed conservatively, the management
should be exclusively the treatment of the hydrocephalus
either using a shunt or a ventriculocisternostomy. Neurovascular compression syndromes on the other hand can be
successfully treated by microvascular decompression.33 For
other intracranial compression syndromes related to a DVA,
management should be conservative with preservation of the
integrity and patency of the venous collector to avoid venous
ischemic complications.
Flow-Related Symptomatology
In DVAs, as extreme variations of normal venous drainage, a
single collector drains an abnormally large parenchymal
territory. This can lead to a more fragile venous outflow
system because the single venous collector can be overloaded
accounting for the dilated medullary veins. In the group of
“flow-related” complications are those DVAs subsumed in
which this fragile equilibrium of in- and outflow is disturbed
and which thereby become symptomatic.
Increase of the Inflow
Considering the increased inflow into a DVA, we found 18
cases of AVMs draining directly through a DVA. In
comparison to AVMs draining through regular veins, these
patients presented with a high rate of parenchymal hemorrhage. In our cases, and in those documented by angiog-
raphy in the literature, the morphology of the medullary
veins draining into the DVA were characteristically dilated
and ectatic. This chronic increased pressure within the
DVA may change its natural history by increasing the risk
of venous rupture because of an already fragile venous
outlet.
Associations of 2 or more different cerebral vascular
malformations are not uncommon, the most well known
being the association of cavernomas and DVAs. Although
the latter are most likely due to a common pathomechanism, the exceedingly rare combination of a DVA with an
AVM is presumably purely by coincidence.47,48 There have
been reports describing a hybrid malformation consisting
of an AVM and a DVA as a rare subset of mixed
cerebrovascular malformations.47 In certain large and complex DVAs, a slightly early venous filling can be present,
which has led to the description of so-called “mixed
vascular malformations” with what has been described as
“microshunts.”47,49 In our experience, an increased medullary blush is not related to a true shunt, but rather
demonstrates a rapid transit time because of enlarged
medullary veins and we have found no symptomatic cases
in our databank nor in the literature. Therefore, it is our
opinion that the association of a true AVM with a DVA
exists as a distinct and rare entity that is associated with a
higher risk of hemorrhage and complications. Following
this line of thought, there is in our practice a place for
preventive treatment in an asymptomatic patient with a
shunt draining through a DVA.
The management of these lesions is aimed at treatment of
the AVM with surgery,47,50 radiosurgery,48 or embolization
with preservation of the patency of the DVA because it has
been described that the proper treatment of the AVM decreases the risk of complication of the DVA.51
Restriction of Outflow
Restriction of the venous drainage from a DVA can occur by
2 pathomechanisms: by an anatomic obstacle to the normal
drainage (secondary to stenosis or thrombosis of the DVA
or its drainage vein) or by a “functional” obstacle that can
be caused by an increase in the venous pressure secondary
to a distant arteriovenous shunt (dural arteriovenous shunt
or AVM).
The restriction of outflow can produce a variety of
morphological and clinical presentations ranging from
venous congestive edema to hemorrhage similar to sinus
and cortical venous thrombosis. Clinical symptomatology
is therefore highly variable and dependent on the cause,
localization, extension, and time of development of the
venous occlusion. Signs of increased intracranial pressure
can be present; neurological deficits and seizures can occur
in the group of patients in whom focal congestive and
hemorrhagic lesions occur. A congestive (ie, vasogenic)
edema with a breakdown of the blood– brain barrier is a
potential presentation that can proceed to hemorrhagic or
true ischemic transformation, the latter being most likely
due to a critical diminution in cerebral blood flow with
subsequent cytotoxic edema.52 According to some authors,
thrombosis of a DVA is always symptomatic.53,54 Early
Pereira et al
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recanalization of the venous collector will presumably
prevent this complication.55 Consequently, anticoagulation
was suggested as the first-line treatment in symptomatic
DVAs even in the presence of hemorrhage, similar to the
treatment of sinus or venous thrombosis.53,56
Functional obstruction of the venous drainage is present
in associated venous hypertension after an arteriovenous
shunt. The association between a symptomatic DVA and a
dural arteriovenous shunt has been reported previously.51,53 Dural arteriovenous shunts invariably increase the
pressure in the dural venous sinuses. This causes mild to
severe disturbances in the draining functions of other
veins. A more fragile venous system with decreased
flexibility that may be present in DVAs will be more prone
to becoming symptomatic leading to venous congestive
edema or ischemia.57 As already described, the aim should
be the treatment of the arteriovenous shunt with preservation of the DVA.
Idiopathic Symptomatology
Given the previously mentioned considerations, the pathomechanisms of 92.7% of all symptomatic DVAs could be
explained, however, in a fraction of the cases described; no
clear pathomechanism could be identified. They presented
mainly with intraparenchymal hemorrhage. Whether this was
due to an unrecognized small cavernoma or a resolved
thrombosis or truly due to a rupture of the DVA can therefore
not be decided. It is of interest, however, that in most
symptomatic idiopathic cases, large and complex DVAs were
present.
Evaluation of Symptomatic Cases
In cases of hemorrhage related to DVAs, cavernomas are the
most often encountered etiology. However, especially in
large and complex DVAs, other mechanisms have to be kept
in mind. We have identified the following characteristics for
symptomatic DVAs: large and complex DVAs with changes
on MRI suggesting venous congestion, acute or subacute
ischemic changes, asymmetrical appearance of the medullary
zones, and association with true arteriovenous malformation.
MRI is the diagnostic modality of choice to diagnose DVAs,
their potential complications, and associated pathologies.
Although not routinely performed in this series, diffusion and
perfusion sequences will be helpful for detecting venous
congestion. In our opinion, thrombotic complications of
DVAs require the same treatment and laboratory workup as
cortical venous or sinus thrombosis, ie, anticoagulation treatment with investigation of procoagulating factors or prothrombotic conditions.58 Although MRI is sufficient for
routine evaluation, we think that angiography can add to the
understanding of the hemodynamics of the DVA, potential
ruptured points, venous stenosis, and other associated pathologies such as dural arteriovenous shunts or AVMs. A
superselective injection may be required if a conventional
angiogram is not capable to define the diagnosis in
suspicious cases (repetitive hemorrhages with focal hematoma, venous asymmetry).
Symptomatic Developmental Venous Anomalies
3213
Conclusion
The true incidence of vascular complications related to a
DVA is unknown. DVAs should still be considered to be
benign lesions, although in exceedingly rare cases, they can
be symptomatic according to the aforementioned conditions.
The pathomechanism should be identified for proper management. The integrity of the DVA needs to be preserved
irrespective of the treatment of choice.
Acknowledgments
We thank 2 anonymous reviewers for their thorough and extensive
review and their very helpful comments and suggestions.
Disclosures
None.
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Pathomechanisms of Symptomatic Developmental Venous Anomalies
Vitor M. Pereira, Sasikhan Geibprasert, Timo Krings, Thaweesak Aurboonyawat, Augustin
Ozanne, Frederique Toulgoat, Sirintara Pongpech and Pierre L. Lasjaunias
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Stroke. 2008;39:3201-3215; originally published online November 6, 2008;
doi: 10.1161/STROKEAHA.108.521799
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