Relevant Cerebro-Vascular Anatomy
for Carotid Intervention
Ricardo A Hanel, MD
Elad Levy, MD
L N Hopkins, MD
Cerebrovascular Anatomy
Why should I learn it For CAS ?
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Basic anatomy and collateral
circulation is enough
Always obtain baseline films
for comparison
Knowing the anatomy helps
avoid complications
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2 ICA’s &VA’s carry
20% of Cardiac OP
ICA’s fixed from skull
base to supraclin ICA
VA’s fixed in vertebral
foramen
Carotid artery interventions
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Clinical applied Anatomy will influence:
– The best therapeutic option (CEA x CAS)
– The best Access (femoral, brachial, direct)
– Device selection
– Complication avoidance
– Complication management
Aortic Arch Views
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Arch angio to assess
access
LAO 30-45 degrees best
Multiple views…origin ds
RAO 20.. R subclavian
from RCCA
Carotid Artery
Petrous Carotid
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Variability enormous
Bifurcation C1 – T2
Best working view…
lat/obl
Bony landmarks …
-Unsubtract
Skull Base
ICA
ECA
Cervical Carotid Views
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Obtain AP, Lateral and
Oblique projections
Clear ICA origin from ECA
Evaluate for dissection,
thrombus, calcium, kinks
Measurements using
NASCET criteria
– 1 - (Stenosis diameter/Nontapered segment diameter)
Cervical ICA
“No Branches”
Hi flow…Don’t overdilate!
Fixed near skull base
Carotid Sinus
What is this??
Where to put the filter?
Connections
ICA to VA
Pcomm
Otic
Primitive trigeminal
Hypoglossal
Pro atlantal
ECA anatomy
ECA Branches
1. Key source of collateral
2. Anastomoses to ICA or VA
3. Stent will not occlude ECA
When handling the ECA remember…
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EC-IC anastomosis common
May not be seen on angiogram
With major vessel occluson these
anastomosis may hypertrophy
ECA embolus may cause stroke
BE AWARE!
The GuardWire® Balloon Protected
Procedure
Pre-intervention Cine
E. Deflate the GuardWire® protection
balloon and evaluate final result
Post-intervention Cine
The GuardWire® Balloon Protected Procedure
SVG with covered stent sample
Carotid stenting sample
Complication: Visual Loss due to retrograde embolization
of retinal arteries via ECA branches
ICA Anatomy
Supraclinoid ICA
Petrous ICA
Ophthalmic a
Cavernous ICA
Base of Skull
Onward and Upward…
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ICA becomes fixed 2-3mm proximal to
skull base
Petrous ICA up to supraclinoid ICA
fixed in bone/ligamentous/dural
encasement
Intracranial vessels more mobile but
fragile and easily damaged/ruptured
Skull Base From Below
ANT
•Horizontal Petrous ICA
ICA Entrance
Post
Skull Base From Above
Ant
Horiz Petrous ICA
Post
Petrocavernous ICA
Side View - Right
Cavernous
Ascending Petrous
Cavernous – Supraclinoid ICA
Anterior Medial Loop
Horizontal
Cavernous ICA
Supraclinoid ICA
Post Communicating
Perforators
Quiz … What is this??
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Although uncommon,
carotid-basilar
anastomoses, other
then PComm, may
occur:
– Persistent trigeminal
artery (0.25%)
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From Cavernous ICA to
basilar
Ascending
Petrous ICA
Primitive
Trigeminal
Intracranial Vascular Anatomy
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After giving origin to the Ophthalmic
A, PComm and Ant Choroidal artery
the ICA finally bifurcates into the
Anterior Cerebral Artery - ACA and
Middle Cerebral Artery – MCA
Intracranial Vascular Anatomy
A Must….pre op AP and Lateral Angio
Have them handy!!!!
Variations are the Rule
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Many variations of
these vessels
Always have pre op
films to compare in
case of trouble
And always do a
baseline Neuro
exam pre op
3 M-2
branches
MCA embolus ?????
The Circle of Willis
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Connection between:
– Carotid-basilar system
– Rt/Lt side
– Vessels involved:
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ACAs & AComm
ICAs & PComms
PCAs
Basilar
T/F : The Circle is Always Intact ??
Pcomm
Acomm
Pcomm
Pcomm
The Circle of Willis
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The Circle of Willis is
complete in only 3040% of the cases
Many variations
Hypoplasia of one of
the A-1 segments of
the ACAs…
Or ICA stenosis???
A-1
What is this?
MCA & ACA Anatomy
ACA
MCA
ACA
A-2
Acomm
A-1
M-1
M-2
MCA
Where is the ACA ?
MCA …
Many Variations
ACA Anatomy
A-2
A-2
PComm
A-1
Variations, variations,
variations …
Message ???
Vertebral Artery Anatomy
Rich Muscular Collateral
Variations, variations,
variations …
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A complete diagnostic angiogram with
clinical/anatomical correlation should
be performed and available before any
major intervention
ICA Occlsion
R ICA Occl with Collateral
…Circle of Willis
L Carotid
R Vertebral
R ICA Occl with Pial Collateral
R ICA Occl with
Vertebral Collateral to MCA
PComm
ICA Occlusion with
Ophthalmic Collateral
Ophthalmic
To ICA
L CCA
R ICA Occl with Ophthalmic
and Pial Collateral
Vascular Territories
Normal Angiogram
Capillary Phase
Capillary Phase
Pre Embolus
Post Embolus
Complications
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Interventional procedure
going uneventfully
until…..
Pt agitated &
hemiparetic
What is this?
What should you do?
Complications
Intracerebral Hemorrhage
ACA and MCA spread…Barrel Shift
Hemorrhage
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CT Scan
You DO NOT need to
angiographically visualize
extravasation to have bleeding.
What is This ?
Proceed with CAS ??
And this ?
…And This ??
Dangerous Anatomy
Elderly Patient
Stay Away!!
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“Corkscrew” Carotid
Trouble …for sure!
Judgement!!
Backing out is OK
Causing a Stroke is
Not
Roubin
Conclusion…
Catheter skills
+
Anatomic Knowledge
=
Better results