CEREBRAL
ARTERIOVENOUS
MALFORMATIONS
AVM,a
TLA for
the CNS
Incidence
0.52% at autopsy
Slight male preponderance (1.09 to
1.94)
Congenital lesions (although
rarely familial)
Embryology
First half of third week of gestation
epiblastic cells migrate to form mesoderm
mesodermal cells differentiate to arterial and
venous vessels on the surface of the embryonic
nervous system
Embryology
First half of third week of gestation
epiblastic cells migrate to form mesoderm
mesodermal cells differentaite to arterial and
venous vessels on the surface of the embryonic
nervous system
Seventh gestational week
vessels sprout branches & penetrate developing
brain
reach the gray-white interface,either loop back
to pial surface or traverse entire neural tube,
thus epicerebral & transcerebral circ'n
eventually connect arterial and venous systems
Pathology & Pathophysiology
absence of normal
capillary system
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
vessels change with
time
may develop
aneurysms
parenchymal changes
within and around
the lesion
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
vessels change with
time
may develop
aneurysms
parenchymal changes
within and around
the lesion
site frequency is
proportional to
brain volume
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
vessels change with
time
may develop
aneurysms
Clinical presentation
95% have symptoms by age of 70
years
Clinical presentation
95% have symptoms by age of 70
years
peak presentation second to fourth
decade
Clinical presentation
95% have symptoms by age of 70
years
peak presentation second to fourth
decade
– high output failure,neonate,vein
of Galen
– hydrocephalus,first decade
– headache,hemorrhage,seizures,2nd
& 3rd
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
– dural sinuses
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
– dural sinuses
– ischaemia
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
– dural sinuses
– ischaemia
– cardiac output
Clinical presentation
D e f ic it s
10%
He ad ac h e s
10%
S e iz u r e s
30%
He m or r h age
50%
Hemorrhage
AVM
– rupture not a
function of size
Aneurysm
– rupture related to
aneurysm size
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
– mortality 6 to
13.6%
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
– mortality 30-50%
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
– mortality 6 to
13.6%
lower rebleed
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
– mortality 30-50%
– higher rebleed
mortality rate
(13%)
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
– mortality 6 to
13.6%
– lower rebleed
mortality rate (1%)
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
– mortality 30-50%
– higher rebleed
mortality rate
(13%)
vasospasm common
Hemorrhage - AVM
Nonetheless,risk of major,
incapacitating,or fatal
hemorrhage in untreated lesion is
40 to 50%
Hemorrhage - AVM
Nonetheless,risk of major,
incapacitating,or fatal
hemorrhage in untreated lesion is
40 to 50%
Yearly risk of initial hemorrhage
~3%
Rebleed in first subsequent year
6-18%,reducing to ~3% again
thereafter
Pediatric prognosis worse than
Spetzler &
Martin
Grading
System
Criteria Score
Size of Nidus
Small (<3cm) 1
Medium (3-6cm) 2
Large (>6cm) 3
Eloquence of Adjacent Brain
No 0
Yes 1
Deep Vascular Component
No 0
Yes 1
Treatment Options
Surgical Resection
Treatment Options
Surgical Resection
Endovascular Embolisation
Treatment Options
Surgical Resection
Endovascular Embolisation
Stereotatic Radiosurgery
Treatment Options
Surgical Resection
Endovascular Embolisation
Stereotatic Radiosurgery
Multimodal Therapy
Treatment Options
Surgical Resection
Endovascular Embolisation
Stereotatic Radiosurgery
Multimodal Therapy
Conservative Management
Normal Perfusion
Pressure
Breakthrough Theory
R.F,Spetzler et al
Normal perfusion pressure
breakthrough theory
Loss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal perfusion pressure
breakthrough theory
Loss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal hemispheric vessels are chronically
maximally dilated to attempt to divert flow
from the AVM
Normal perfusion pressure
breakthrough theory
Loss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal hemispheric vessels are chronically
maximally dilated to attempt to divert flow
from the AVM
Obliteration of the AVM diverts all flow to
these maximally dilated vessels which have
lost their normal control mechanisms
Normal perfusion pressure
breakthrough theoryLoss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal hemispheric vessels are chronically
maximally dilated to attempt to divert flow
from the AVM
Obliteration of the AVM diverts all flow to
these maximally dilated vessels which have
lost their normal control mechanisms
Results in loss of protection of the
capillary bed,with edema and hemorrhage
Arterial inflow
Mathematical Models
Arterial inflow
Nidus
Mathematical Models
Arterial inflow
Nidus
Venous Outflow
Mathematical Models
Anaesthesia
Technique
ARTERIOVENOUS
MALFORMATIONS
AVM,a
TLA for
the CNS
Incidence
0.52% at autopsy
Slight male preponderance (1.09 to
1.94)
Congenital lesions (although
rarely familial)
Embryology
First half of third week of gestation
epiblastic cells migrate to form mesoderm
mesodermal cells differentiate to arterial and
venous vessels on the surface of the embryonic
nervous system
Embryology
First half of third week of gestation
epiblastic cells migrate to form mesoderm
mesodermal cells differentaite to arterial and
venous vessels on the surface of the embryonic
nervous system
Seventh gestational week
vessels sprout branches & penetrate developing
brain
reach the gray-white interface,either loop back
to pial surface or traverse entire neural tube,
thus epicerebral & transcerebral circ'n
eventually connect arterial and venous systems
Pathology & Pathophysiology
absence of normal
capillary system
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
vessels change with
time
may develop
aneurysms
parenchymal changes
within and around
the lesion
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
vessels change with
time
may develop
aneurysms
parenchymal changes
within and around
the lesion
site frequency is
proportional to
brain volume
Pathology & Pathophysiology
absence of normal
capillary system
usual function
displaced
asymptomatic at
birth
vessels change with
time
may develop
aneurysms
Clinical presentation
95% have symptoms by age of 70
years
Clinical presentation
95% have symptoms by age of 70
years
peak presentation second to fourth
decade
Clinical presentation
95% have symptoms by age of 70
years
peak presentation second to fourth
decade
– high output failure,neonate,vein
of Galen
– hydrocephalus,first decade
– headache,hemorrhage,seizures,2nd
& 3rd
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
– dural sinuses
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
– dural sinuses
– ischaemia
Clinical presentation
factors contributing to symptoms
– vessel walls,flow and pressures
– enlargement and encroachment
– dural sinuses
– ischaemia
– cardiac output
Clinical presentation
D e f ic it s
10%
He ad ac h e s
10%
S e iz u r e s
30%
He m or r h age
50%
Hemorrhage
AVM
– rupture not a
function of size
Aneurysm
– rupture related to
aneurysm size
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
– mortality 6 to
13.6%
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
– mortality 30-50%
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
– mortality 6 to
13.6%
lower rebleed
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
– mortality 30-50%
– higher rebleed
mortality rate
(13%)
Hemorrhage
AVM
– rupture not a
function of size
– no marked increase
with exercise,
pregnancy,trauma
– arteriovenous,
therefore less
severe
– mortality 6 to
13.6%
– lower rebleed
mortality rate (1%)
Aneurysm
– rupture related to
aneurysm size
– increase with
trauma exercise,
end pregnancy
– arterial,therefore
more severe
– mortality 30-50%
– higher rebleed
mortality rate
(13%)
vasospasm common
Hemorrhage - AVM
Nonetheless,risk of major,
incapacitating,or fatal
hemorrhage in untreated lesion is
40 to 50%
Hemorrhage - AVM
Nonetheless,risk of major,
incapacitating,or fatal
hemorrhage in untreated lesion is
40 to 50%
Yearly risk of initial hemorrhage
~3%
Rebleed in first subsequent year
6-18%,reducing to ~3% again
thereafter
Pediatric prognosis worse than
Spetzler &
Martin
Grading
System
Criteria Score
Size of Nidus
Small (<3cm) 1
Medium (3-6cm) 2
Large (>6cm) 3
Eloquence of Adjacent Brain
No 0
Yes 1
Deep Vascular Component
No 0
Yes 1
Treatment Options
Surgical Resection
Treatment Options
Surgical Resection
Endovascular Embolisation
Treatment Options
Surgical Resection
Endovascular Embolisation
Stereotatic Radiosurgery
Treatment Options
Surgical Resection
Endovascular Embolisation
Stereotatic Radiosurgery
Multimodal Therapy
Treatment Options
Surgical Resection
Endovascular Embolisation
Stereotatic Radiosurgery
Multimodal Therapy
Conservative Management
Normal Perfusion
Pressure
Breakthrough Theory
R.F,Spetzler et al
Normal perfusion pressure
breakthrough theory
Loss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal perfusion pressure
breakthrough theory
Loss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal hemispheric vessels are chronically
maximally dilated to attempt to divert flow
from the AVM
Normal perfusion pressure
breakthrough theory
Loss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal hemispheric vessels are chronically
maximally dilated to attempt to divert flow
from the AVM
Obliteration of the AVM diverts all flow to
these maximally dilated vessels which have
lost their normal control mechanisms
Normal perfusion pressure
breakthrough theoryLoss of autoregulation and carbon dioxide
reactivity in presence of large arteriovenous
malformation.
Normal hemispheric vessels are chronically
maximally dilated to attempt to divert flow
from the AVM
Obliteration of the AVM diverts all flow to
these maximally dilated vessels which have
lost their normal control mechanisms
Results in loss of protection of the
capillary bed,with edema and hemorrhage
Arterial inflow
Mathematical Models
Arterial inflow
Nidus
Mathematical Models
Arterial inflow
Nidus
Venous Outflow
Mathematical Models
Anaesthesia
Technique
