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Arteriovenous Malformation (AVM) of Brain AVM Cerebral AVM Vascular Malformation
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Arterio-Venous Malformations (AVM) of Brain
Dhaval ShuklaAdditional Professor of Neurosurgery
NIMHANS, Bangalore
Normal Blood Vessels
Abnormal Connection of Blood Vessels
AVM
Cause of AVM
• Not known
• Usually congenital
• Not hereditary
• Most AVMs do not grow or change in size
– Blood vessels may increase in diameter
– AVMs shrink due to clots in parts of an AVM
– AVMs may enlarge due to redirection of blood flow
Epidemiology
• Less than one percent of the general
population
• One in 200–500 people may have an AVM
• More common in males than females
Sites
Symptoms
• Symptoms may vary with location
• More than 50 % present with brain hemorrhage
• 20% - 25% with seizures
• Localized headache
• 15% may have difficulty with movement, speech
and vision
Brain hemorrhage
• Abnormal and “weakened” blood vessels over time eventually burst from the high pressure of blood flow from the arteries
• 1–3 % chance per year of bleeding
• Risk of bleeding = 105 – age (in years)
Brain hemorrhage
• 10–15% risk of death
• Loss of normal function– Temporary – Permanent: 20–30%
• Brain damage depends on – Amount of blood – Site of bleed
Symptoms of hemorrhage
Rebleeding risk
• More during first year after initial bleeding
– 6% to 18%
• Higher in the first year after the second bleed
– 25%
• Higher risk of bleeding in ages 11 – 35 years
Diagnosis
• Computed tomography (CT)– Hemorrhage
• Magnetic resonance imaging (MRI) – Location and size
CT scans showing hemorrhage due to AVM
MRI of AVM
Diagnosis
• Cerebral angiogram (DSA) – Required for treatment– Insertion of a catheter (small tube)
through an artery in leg to each vessels going to brain
– Injection of contrast material (dye)– Taking pictures of all blood vessels
of brain
Treatment
• Bleed
• Easily accessible
• Not too large
Medical Therapy
• Avoid
– Any activities that may excessively elevate blood
pressure
– Blood thinning drugs like warfarin
• Regular checkups with a neurologist
• Antiepileptic drugs
Surgery
Indications
• Bleeding
• Easily accessible
• Small or medium
Stereotactic radiosurgery(Gamma Knife)
Indications• Small• Difficult to reach by surgeryMechanism• Produce direct damage to the vessels
that will cause a scar and allow the AVM to “clot off”
• Takes 2 years to cure AVM
Endovascular treatmentIndications• Usually for a part of AVM
• Rest of AVM requires treatment either with surgery or Gamma Knife
• Occasionally for small AVMMechanism• Blocking off abnormal blood vessels to stop blood
flowing to AVM– Liquid tissue adhesives (glues)– Coils– Particles and other materials used
Endovascular treatment
Outcome – Surgery
• Small AVMs– Cure: 94 to 100%– Morbidity and mortality: <10%
– Bleeding– Infection– Paralysis or loss of function (temporary or permanent)– Convulsions (controllable or uncontrollable) – Coma (reversible or irreversible)– Death
– Seizure-free: 81%
• Large AVMs– Morbidity and mortality: 25%
Outcome – Gamma Knife
• Cure: 61% to 87% (after 2 years)
• Morbidity (during 2years): 1 to 36%
• Mortality (during 2years): 0 to 9%
• Seizure-free: 43%
Outcome – Endovascular treatment
• Cure: 5 to 40%
• Morbidity rates: 8% -10%
– Same as for surgery
• Mortality rate: 1%
• Seizure-free: 50%
Conclusion
• AVMs are difficult to treat and treatment decision should be individualized
• If AVM has not ruptured (never bled) there is no need of specific treatment. • Patient requires only symptomatic treatment
• Whenever possible microsurgery is the best option
• Gamma Knife is an optional treatment for inaccessible AVM
• Endovascular treatment is not effective as stand alone for most cases
• Medium size AVMs require multimodal treatment
• Very large AVMs should not be treated