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 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
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 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
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
