Details of Vein of galen malformation- types classification and management for Neurology and Neurointervention residents

1. VEIN OF GALEN
MALFORMATION
Dr SAMEEP KOSHTI

3. background
• A vein of Galen aneurysmal malformation (VGAM) is a fistulous
arteriovenous malformation unique to early childhood.
• It is located in the subarachnoid space in the choroid fissure.
• embryologically related to the development of the choroid plexus.
• <1% of all AVM

4. VEIN OF GALEN DEVELOPMENT
• Expansion of the telencephalic choroid plexus on the roof of the diencephalon
• induces development of a midline dorsal vein of the prosencephalon(MARKOWSKI)
draining the bilateral choroid plexus.
• remains functional till first half of the third month of development.
• Progression of intracerebral vascularization result in the formation of the
• paired internal cerebral veins (ICVs)
• This step leads to regression of the median vein of the prosencephalon except for the
most caudal portion, which joins with the ICVs to form the vein of Galen.
• The RASA1 mutation has been reported in some cases of VGAM.

6. Classification
• The concept of this disease was refined by Lasjaunias's group,
1. VGAM
• as arteriovenous fistulas draining to the embryonic precursor of the vein of Galen called the median vein
of prosencephalon.
• subclassified VGAM further into the
• choroidal type
• mural type.
2. vein of Galen aneurysmal dilation (VGAD)
• cause dilation of the “true” (embryologically matured) vein of Galen
• due to pial or dural arteriovenous shunts draining into the “true” vein of Galen or its tributary.
3. vein of Galen varix (VGV).
• VGV is a dilated vein of Galen without arteriovenous shunts.

9. Chororidal VGAM
• consists of multiple fistulas to the embryonic median vein of prosencephalon (Of
MARKOWSKI)
• mainly located in the velum interpositum cistern medial to the choroidal fissure.
• The principal arterial feeders are
• the choroidal arteries,
• including the bilateral anterior and
• medial and lateral posterior choroidal arteries and
• the anterior cerebral arteries through the pericallosal arcade.
• additional supply from the quadrigeminal arteries and the thalamoperforators.
• These feeders are connected to one another and form artery-to-artery anastomosis
before the fistula points.
• Some fistulas of this type are extremely high flow
• manifest as high-output cardiac failure in the newborn period.
• Other smaller fistulas with slower flow
• manifest as the hydrodynamic disorder or other problems.

10. Quadrigeminal• The cistern of the
velum interpositum
• the space
between the roof
of the third
ventricle and
• the fornix of the
corpus callosum.

13. MURAL VGAM
• single or a few fistulas at the wall of the dilated posterior portion of the median
vein of prosencephalon.
• located either in the
• velum interpositum cistern or
• the quadrigeminal cistern
• The quadrigeminal and/or the posterior choroidal arteries often supply them.
• In contrast to the choroidal type VGAM,
• they have fewer fistulas and
• typically have more round dilation of the median vein of prosencephalon.
• manifest in infancy as
• symptoms of the hydrodynamic disorder, such as macrocephaly, hydrocephalus, and failure
to thrive,
• although it may be associated with relatively mild cardiac failure or asymptomatic
cardiomegaly.

14. VGAD
• secondary dilation of the vein of Galen
• due to draining of arteriovenous shunting to the deep venous system.
• In contrast to VGAM,
• the midline ectatic vein in VGADs is the “true” embryologically matured vein of Galen and,
• therefore, receives drainage from the normal brain as well as the malformation.
• VGAD is
• commonly due to pial AVMs,
• but dural arteriovenous fistula (AVF)
• can also cause dilation of the vein of Galen.

15. Pial AVM with VGAD
• pial or parenchymal AVM that
• drains into the dilated vein of Galen or its tributary.
• Dilation of the vein of Galen is
• secondary to outflow obstruction.
• Outflow obstruction can be
• functional, due to high flow fistulas, or
• mechanical, due to progressive occlusion of the jugular bulb and the sigmoid sinus, or both.
• blood flow refluxes into other normal cerebral veins
• internal cerebral,
• vermian,
• hippocampal,
• Basal vein,
• medial ventricular,
• internal parietal, or internal occipital veins, or
• other normal tributaries of the vein of Galen).
• Patency of the embryonic sinuses, such as the falcine sinus and the occipital sinus, is
often seen in both VGAD and VGAM.

16. Contd..
• manifests in
• childhood or young adulthood as
• intracerebral hemorrhage,
• focal neurological deficit, or
• seizures.
• High-output cardiac failure or
• hydrodynamic disorder can also occur in young children.
• MRI or MR angio :
• Demonstration of transmesencephalic feeders by magnetic resonance imaging (MRI) or
angiography confirms the pial nature of the lesion and thus the VGAD.
• Transmesencephalic feeders are projected below the P2 segment of the posterior cerebral artery on the
lateral view of vertebral artery angiograms.
• For treatment,
• transvenous occlusion of the vein of Galen is contraindicated in VGAD because it may
produce hemorrhage or venous infarct of the deep cerebral veins, the outflow of which is
occluded.

17. DURAL AVM WITH VGAD
• acquired lesion
• usually manifesting in the fourth or fifth decade of life,
• in which arteriovenous shunts are often located in the wall of the vein of Galen itself.
• Cortical venous reflux from the vein of Galen to afferent cerebral veins is frequently noted.
• Typical clinical presenting symptoms and signs
• headaches,
• seizures, and
• those of cerebral hemorrhage and
• Progressive cognitive dysfunction leading to dementia due to cerebral venous hypertension.
• The arterial supply is
• predominantly from dural falcotentorial arteries
• from the internal and external carotid arteries and
• the vertebral artery,
• the vasa vasorum to the wall of the vein of Galen from the pial arteries.
• Endovascular treatment is difficult
• because the transvenous approach was often not feasible and there were too many feeders from both carotid and vertebral
arteries for transarterial embolization.
• Introduction of the nonadhesive liquid embolic agent Onyx (Covidien) for embolization of dural AVMs has
• significantly improved treatment result for this type of dural AVMs because
• a large volume of this agent can be injected through one feeder to occlude an extensive dural vascular network supplied by multiple feeders and shunting
to the dilated vein of Galen.

18. VEIN OF GALEN VARIX
• dilation of the vein of Galen without presence of an arteriovenous shunt.
• Two types in children.
• 1. transient asymptomatic dilation of the vein of Galen
• in neonates
• presenting with cardiac failure from an etiology other than VGAM.
• This dilation is usually noticed on an ultrasound study and disappears several days after improvement of
cardiac conditions.
• 2. anatomic variation
• when venous drainage of the brain converges towards the deep venous system,
• such as in the presence of a developmental venous anomaly.
• asymptomatic
• Predispose to future venous thrombosis and ischemic symptoms due to lack of compliance.

19. ANGIO-ARCHITECTURE
• The existence of high-flow fistulas to the median vein of prosencephalon
• keeps this vein patent and
• suppresses the development of ICV
• Therefore, the dilated vein of Galen should not be occluded to prevent infarction
or haemorrhage of cerebral structures, at least at the beginning of treatment.
• The straight sinus is often absent in VGAMs, and
• the dilated median vein of prosencephalon frequently drains to the embryonic
falcine sinus,
• which typically connects to the posterior third of the superior sagittal sinus.
• Both embryonic falcine sinus and straight sinus can coexist in some VGAMs.

20. CLINICAL MANIFESTATIONS
•high-output cardiac failure
• In neonates
•symptoms due to venous hypertension secondary to the
hydrodynamic disorder
• Infants and children
•Melting brain syndrome

21. CARDIAC FAILURE MANAGEMENT
• diuretics and fluid restriction to reduce cardiac preload.
• Mechanical ventilation may be necessary for severe heart failure.
• Cardiac output
• increasing cardiac contractility with an inotropic agent such as a β1-receptor agonist.
• Phosphodiesterase inhibitors have both inotropic and vasodilation effects
• dobutamine and dopamine
• used to augment myocardial contractility.
• Nitric oxide is used for pulmonary hypertension.
• The goal of medical treatment
• control the cardiac failure so that the baby can tolerate oral feeding and gain weight.
• If the baby can be discharged home,
• treatment for the VGAM is scheduled at approximately 5 months of age.
• If medical treatment is not sufficient to control cardiac failure,
• the patient needs emergency embolization in the neonatal period.
• The cardiac status of the patient usually improves significantly if embolization decreases the flow through the VGAM by
approximately 50% by

22. HYDRODYNAMIC DISORDER
• state of the brain with disturbed (CSF) absorption and venous hypertension due to
intracranial arteriovenous shunting.
• In neonates and infants, medullary veins (Not arachnoid granulations) are presumed to
be the main absorption pathway for the CSF.
• Macrocranium
• Due to enlarged CSF space through enlargement of the sutures
• the ventriculomegaly (impaired CSF production)
• raised ICP
• developmental delay, and
• mental retardation develop.
• Thickening of the diploic space of the skull can also occur owing to development of
collateral circulation to the scalp veins and lymphatic channels

23. • Venous hypertension
• in tributaries of cavernous sinuses
• exophthalmos,
• Engorgement of the facial veins
• occasional epistaxis.
• pial cortical venous reflux,
• seizures, hemorrhages, and neurological deficits, can develop
• Posterior fossa
• Tonsillar prolapse
• Indication of endovascular embolization
• VENTRICULAR SHUNT
• Associated with complications
• Brain edema (due to reversal of ventricle to SSS pressure gradient)
• Slit ventricles
• Subdural hematoma

24. Melting Brain syndrome
• venous hypertension  decreased CBF  brain parenchyma is subacutely and progressively
destroyed, mainly in the white matter.
• The ventricular system is enlarged but ICP is not elevated.
• occur in fetuses, neonates, and infants
• but is not observed in adults.
• associated with all kinds of AVFs, including VGAMs, pial AVMs, and dural sinus malformations.
• occurs bilaterally and symmetrically,
• Significance :
• In general, emergency treatment is indicated when the early stage is detected,
• because it tends to progress rapidly and irreversibly.
• In relation to VGAM, melting brain syndrome tends to occur in fetuses and neonates and indicates poor prognosis.

25. TREATMENT GOALS AND PRINCIPLES
• The final goal of treatment for VGAM
• is complete obliteration of the lesion followed by normal development without neurological deficits.
• The immediate treatment goal :
• depends on the age and presentation of the patient.
• The primary goal of treatment in neonates :
• to alleviate CHF to help the patient tolerate oral feeding and allow weight gain.
• Once this goal is achieved, the patient is discharged with oral cardiac medication and further treatment is planned
for several months later.
• Careful monitoring for
• enlargement of CSF spaces and
• appearance of new subcortical calcifications is accomplished
• radiographically with plain CT head at intervals of 6 to 10 weeks as well as
• clinically with head circumference measurements / developmental achievements / neurological examinations until the patient is about 5 to 8
months of age, when endovascular treatment is optimal.
• Angiography not indicated for neonates.
• If CT / USG / MRI demonstrates significant brain damage,
• Treatment is not indicated because clinical outcome is poor even if the lesion is anatomically cured.

26. Contd..
• For infants and children,
• the immediate goal
• to restore normal hydrovenous equilibrium to permit normal development of the patient.
• to avoid ventricular shunt placement by performing timely endovascular treatment.
• Transarterial embolization is effective in decreasing the venous pressure,
• Urgent embolization (Only if there is no significant hydrocephalus)
• if the head circumference rapidly increases,
• clinical milestone regression or developmental delay is noticed, or
• CT or MRI detects increased CSF spaces, subcortical calcifications, or other evidence of increased ICP.
• After full development of hydrocephalus
• the effect of embolization is usually insufficient,
• third ventriculostomy or ventricular shunt placement should then be considered.
• Embolization should be avoided at least for several days after the ventricular shunt is placed,
• in order to avoid the risk of upward cerebellar herniation secondary to rapid decrease in supratentorial
pressure.

27. • complete obliteration of the lesion can usually be achieved in
• For a mural VGAM,
• one or two sessions of endovascular treatment.
• For choroidal type VGAM,
• several sessions of staged embolization may be necessary over several years
• If a patient is clinically stable,
• the next treatment is usually planned for 3 to 6 months after the previous treatment.
• VENOUS REFLUX SIGNS if present even if late referral (some neurological
deficit):
• If cerebral pial venous congestion is sufficient to cause acute focal neurological deficits,
seizures, or hemorrhage,
• emergency endovascular treatment should be performed to reduce cerebral venous
hypertension.

28. Summary of treatment
• indications for early intervention are as follows
• (1) unstable or progressive cardiac failure despite maximal medical treatment,
• (2) development of significant macrocrania or hydrocephalus,
• (3) recognition of developmental delay or venous ischemic changes such as calcifications,
and
• (4) pial venous hypertension.
• Conservative follow-up consists of monthly measurements of head
circumference and weight and MRI at 3-month intervals.
• If MRI shows any sign of development of hydrocephalus or ischemic changes in
the brain parenchyma, endovascular treatment should be performed without
delay.

29. PRETHERAPEUTIC EVALUATION
• (a) physical parameters
• weight and head circumference and their changes over time;
• (b) data about the lesion obtained by MRI, MRA,MRV,
• such as feeders, venous dilation, and sinus occlusion;
• (c) transfontanel ultrasonography, CT, and MRI
• information about the brain, such as congestion, encephalomalacia, atrophy, calcification,
and size of the ventricles
• (d) clinical assessment and cardiac echocardiography
• cardiac status including associated cardiac anomaly, obtained by;
• (e) renal and liver function and coagulation profile.

30. LASJAUNIAS Scoring system
• 21-point neonatal scoring system combining
• cardiac,
• cerebral,
• respiratory,
• hepatic, and
• renal factors.
• According to this system,
• Score < 8  no treatment;
• 8 – 12  emergency endovascular treatment; and
• > 12  medical management until the child is 5 months of age.

31. ENDOVASCULAR TREATMENT
• TRANS-ARTERIAL APPROACH
• transfemoral transarterial embolization is
• first and predominant choice of treatment.
• Trans–umbilical artery approach
• Is possible for newborn patients and
• preferred access because of the small size of the femoral artery
• Adv:
• Less bleeding complications
• N-butyl-cyanoacrylate (NBCA) as a transarterial embolic agent
• is the best choice to close the high-flow fistula site itself,
• High conc: >70 % for closure of high flow fistula

32. TRANSVENOUS
• Transfemoral
• Transtorcular (if venous sinus has been occluded)
• Ensure that there is no connection between the venous pouch and
the veins draining the normal brain.
• Post procedural back pressure changes causes hameorrhage.