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Vein of Galen Malformations
What are vein of Galen malformations?
These are abnormal connections between arteries and deep draining veins of
the brain. The capillaries which normally connect arteries to veins and function
to slow blood flow allowing for the drop off of oxygen and nutrients to the
brain are missing. Since vein of Galen malformations lack capillaries, blood
flow can be fast and this in turn increases the work of the heart. Blood
drainage is towards a single deep draining vein which becomes markedly enlarged
(vein of Galen aneurysm). The result can be heart failure. The high flow of
blood can also interfere with the normal blood drainage of the brain potentially
causing hydrocephalus or 'water on the brain'.
This rare malformation develops in utero. Most often these patients are
newborns with congestive heart failure due to arterial-venous shunting of blood
in the brain.
There are 3 categories of vein of Galen malformations:
Neonates that present with congestive heart failure and a loud intracranial
bruit (noise made by blood turbulence).
Infants presenting with enlarging head, seizures, and developmental delay.
Older children presenting with enlarging head and developmental delay.
How is this diagnosed?
This intra-cranial abnormality may be detected on prenatal ultrasound or MRI.
After birth, this pulsatile flow can be detected by a transcranial doppler. If
the neonate presents with heart failure, a cardiac echo will be done to
establish the severity.
A MRI will be done to establish the venous and arterial vascular anatomy. The
MRI will also assess the status of the surrounding brain, which may be abnormal
secondary to ischemia or hemorrhage.
A MRA may be done to depict the arterial feeders and venous drainage pattern
of the malformation.
An angiogram will be done if the patient requires embolization. This involves a
small incision in the groin area and placing a small catheter in the femoral
artery. This catheter is guided to the brain arteries and images are taken after
x-ray contrast is injected in the catheter to assess the blood vessels. This
test will show the vascular anatomy and the flow dynamics of the blood.
How is this Treated?
The management options, timing of intervention and potential complication
make it imperative that this condition be recognized precisely and accurately
and managed at an experienced center at the optimal moment in time in order to
achieve a normally developing child. This should involve a team of specialists
including a neurointerventional radiologist, neurosurgeon, and cardiologist.
If the neonate is in congestive heart failure, this should be treated first. A
pediatric cardiologist may prescribe cardiac medications, oxygen therapy or even
mechanical ventilation if severe.
(angiogram of patient after embolizing - click for enlarged picture)
Careful and frequent developmental assessments and MRIs are needed to
recognize delays and early hydrocephalus. Treatment should be delayed if
possible until at least 5 months of age.
This is difficult to treat using standard neurosurgical procedures. The
treatment of choice is Embolization.
Embolization involves injection of a glue-like material through a catheter
placed near the malformation in the brain. This treatment will decrease blood
flow through the lesion and may immediately improve the heart failure. Often a
patient will require more than one Embolization. Some patients may be cured by
partial Embolization.
Many patients grow up completely normal after treatment. The risk of treatment
varies but may be as high as 10% for permanent disabling stroke or death.