Arteriovenous Malformation (AVM) of Brain AVM Cerebral AVM Vascular Malformation

1. Arterio-Venous Malformations
(AVM) of Brain
Dhaval Shukla
Additional Professor of Neurosurgery
NIMHANS, Bangalore

2. Normal Blood Vessels
Abnormal Connection of Blood Vessels
AVM

3. 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

4. Epidemiology
• Less than one percent of the general
population
• One in 200–500 people may have an AVM
• More common in males than females

5. Sites

6. 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

7. 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)

8. 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

9. Symptoms of hemorrhage

10. 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

11. Diagnosis
• Computed tomography (CT)
– Hemorrhage
• Magnetic resonance imaging (MRI)
– Location and size

12. CT scans showing
hemorrhage due
to AVM

13. MRI of AVM

14. 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

16. Treatment
• Bleed
• Easily accessible
• Not too large

17. Medical Therapy
• Avoid
– Any activities that may excessively elevate blood
pressure
– Blood thinning drugs like warfarin
• Regular checkups with a neurologist
• Antiepileptic drugs

18. Surgery
Indications
• Bleeding
• Easily accessible
• Small or medium

19. Stereotactic radiosurgery
(Gamma Knife)
Indications
• Small
• Difficult to reach by surgery
Mechanism
• Produce direct damage to the vessels
that will cause a scar and allow the AVM
to “clot off”
• Takes 2 years to cure AVM

20. Endovascular treatment
Indications
• Usually for a part of AVM
• Rest of AVM requires treatment either with
surgery or Gamma Knife
• Occasionally for small AVM
Mechanism
• Blocking off abnormal blood vessels to stop blood
flowing to AVM
– Liquid tissue adhesives (glues)
– Coils
– Particles and other materials used

21. Endovascular treatment

22. 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%

23. 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%

24. Outcome – Endovascular treatment
• Cure: 5 to 40%
• Morbidity rates: 8% -10%
– Same as for surgery
• Mortality rate: 1%
• Seizure-free: 50%

25. 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