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 ? Basic anatomy and collateral circulation is enough Basic anatomy and collateral circulation is enough Always obtain baseline films for comparison Always obtain baseline films for comparison Knowing the anatomy helps avoid complications Knowing the anatomy helps avoid complications

2 ICA’s &VA’s carry 20% of Cardiac OP 2 ICA’s &VA’s carry 20% of Cardiac OP ICA’s fixed from skull base to supraclin ICA ICA’s fixed from skull base to supraclin ICA VA’s fixed in vertebral foramen VA’s fixed in vertebral foramen

Carotid artery interventions Clinical applied Anatomy will influence: 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 Develops from the L 4 th embryonic arch Develops from the L 4 th embryonic arch Branches Branches –Brachiocephalic trunk (Inominate A) –L Common carotid A –L Subclavian A Many variations Many variations Disease alters anatomy and risks Disease alters anatomy and risks

Aortic Arch Views Arch angio to assess access Arch angio to assess access LAO degrees best LAO degrees best Multiple views…origin ds Multiple views…origin ds RAO 20.. R subclavian from RCCA RAO 20.. R subclavian from RCCA

Positioning for an Ideal Arch Angiogram Straight AP 30-45° LAO

Straight and LAO Arch Images

Aortic Arch Views Common Variants: Common Variants: –Bovine origin of LCCA off of Brachiocephalic Trunk 7-20% of patients 7-20% of patients –L Vertebral origin off arch 0.5% of patients 0.5% of patients Proximal to L SCA Proximal to L SCA –Aberrant right subclavian 0.4 to 2% of patients 0.4 to 2% of patients R Subclavian originates from the arch distal to the left subclavian R Subclavian originates from the arch distal to the left subclavian

Common variants A) Brachiocephalic trunk (BCT) and LCCA share a common origin (25- 30%) B) L CCA arises from BCT (7%) C) L Vert arises directly from the arch (0.5%) Osborn A, 1998 D) R subcl. Origin from L

Bovine Arch - 7% ?? Brachial Approach Bovine Arch - 7% ?? Brachial Approach

Uncommon L Arch + Aberrant R Subclavian (0.4-2%) L Arch + Aberrant R Subclavian (0.4-2%) R Arch with aberrant L subclavian R Arch with aberrant L subclavian Rt arch with mirror-image branching Rt arch with mirror-image branching Double Aortic Arch Double Aortic Arch

What is this??

Dextrocardia with mirror-image

And This??

Multiple Anomalies…What ‘s This??

R Subclavian (No R vert)

Supra-aortic vessels (R to L) Supra-aortic vessels (R to L) –R CCA R Vert from RCCA R Vert from RCCA –LCCA –L Vert –L Subclavian –R Subclavian Multiple Anomalies R CCA R VA L CCA L VA R&L Subcl

R Vert arising from R CCA

Weird Anatomy!! Weird Anatomy!!

Carotid Artery Variability enormous Variability enormous Bifurcation C1 – T2 Bifurcation C1 – T2 Best working view… lat/obl Best working view… lat/obl Bony landmarks … Bony landmarks … -Unsubtract -Unsubtract Skull Base Petrous Carotid ECA ICA

Cervical Carotid Views Obtain AP, Lateral and Oblique projections Obtain AP, Lateral and Oblique projections Clear ICA origin from ECA Clear ICA origin from ECA Evaluate for dissection, thrombus, calcium, kinks Evaluate for dissection, thrombus, calcium, kinks Measurements using NASCET criteria Measurements using NASCET criteria –1 - (Stenosis diameter/Non- tapered 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?

Pcomm Otic Primitive trigeminal Hypoglossal Pro atlantal Connections ICA to VA

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… EC-IC anastomosis common EC-IC anastomosis common May not be seen on angiogram May not be seen on angiogram With major vessel occluson these anastomosis may hypertrophy With major vessel occluson these anastomosis may hypertrophy ECA embolus may cause stroke ECA embolus may cause stroke BE AWARE! BE AWARE!

Most Common Extra-cranial Intra-cranial anastomosis EXTRACRANIAL ARTERIESINTRACRANIAL ARTERIES Anterior branch of middle meningeal Ophthalmic (ethmoidal) Anterior meningealAnterior cerebral Petrosquamosal branch of middle meningeal Petrous internal carotid (cranial nerve VII) OccipitalVertebral Neuromeningeal branch of ascending pharyngeal Posterior inferior cerebellar/ anterior inferior cerebellar (cranial nerves IX ‑ XI)

Post-intervention CineE. Deflate the GuardWire ® protection balloon and evaluate final result The GuardWire® Balloon Protected Procedure Pre-intervention Cine

The GuardWire ® Balloon Protected Procedure Carotid stenting sampleSVG with covered stent sample Complication: Visual Loss due to retrograde embolization of retinal arteries via ECA branches

ICA Anatomy Base of Skull Petrous ICA Cavernous ICA Ophthalmic a Supraclinoid ICA

ICA becomes fixed 2-3mm proximal to skull base ICA becomes fixed 2-3mm proximal to skull base Petrous ICA up to supraclinoid ICA fixed in bone/ligamentous/dural encasement Petrous ICA up to supraclinoid ICA fixed in bone/ligamentous/dural encasement Intracranial vessels more mobile but fragile and easily damaged/ruptured Intracranial vessels more mobile but fragile and easily damaged/ruptured Onward and Upward…

Skull Base From Below ICA Entrance Horizontal Petrous ICA ANT Post

Skull Base From Above Ant Post Horiz Petrous ICA

Petrocavernous ICA Side View - Right Ascending Petrous Cavernous

Cavernous – Supraclinoid ICA Anterior Medial Loop Horizontal Cavernous ICA Supraclinoid ICA Perforators Post Communicating

Quiz … What is this?? Quiz … What is this?? Although uncommon, carotid-basilar anastomoses, other then PComm, may occur: Although uncommon, carotid-basilar anastomoses, other then PComm, may occur: –Persistent trigeminal artery (0.25%) From Cavernous ICA to basilar From Cavernous ICA to basilar Primitive Trigeminal Ascending Petrous ICA

Intracranial Vascular Anatomy 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 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 Many variations of these vessels Many variations of these vessels Always have pre op films to compare in case of trouble Always have pre op films to compare in case of trouble And always do a baseline Neuro exam pre op And always do a baseline Neuro exam pre op 3 M-2 branches MCA embolus ?????

The Circle of Willis Connection between: Connection between: –Carotid-basilar system –Rt/Lt side –Vessels involved: ACAs & AComm ACAs & AComm ICAs & PComms ICAs & PComms PCAs PCAs Basilar Basilar T/F : The Circle is Always Intact ??

Acomm Pcomm

The Circle of Willis The Circle of Willis is complete in only % of the cases The Circle of Willis is complete in only % of the cases Many variations Many variations Hypoplasia of one of the A-1 segments of the ACAs… Hypoplasia of one of the A-1 segments of the ACAs… Or ICA stenosis??? Or ICA stenosis??? A-1 What is this?

MCA & ACA Anatomy ACA MCA M-1 M-2 ACA A-2 Acomm A-1

MCA Where is the ACA ?

MCA … Many Variations

ACA Anatomy A-1 A-2 PComm

Variations, variations, variations … Message ???

Vertebral Artery Anatomy Rich Muscular Collateral

Department of Radiology

Variations, variations, variations … A complete diagnostic angiogram with clinical/anatomical correlation should be performed and available before any major intervention A complete diagnostic angiogram with clinical/anatomical correlation should be performed and available before any major intervention

What is this??

Interesting Collateral Asx LCCA origin stenosis R CCA & BILAT VA OCCL Interesting Collateral Asx LCCA origin stenosis R CCA & BILAT VA OCCL R VA(thyrocervical trunk) R CCA(inf thyroid a)

ICA Occlsion 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 L CCA Ophthalmic To ICA

R ICA Occl with Ophthalmic and Pial Collateral

Vascular Territories

Normal Angiogram Capillary Phase

Pre Embolus Capillary Phase Post Embolus

Complications Interventional procedure going uneventfully until….. Interventional procedure going uneventfully until….. Pt agitated & hemiparetic Pt agitated & hemiparetic What is this? What is this? What should you do? What should you do?

Complications Intracerebral Hemorrhage ACA and MCA spread…Barrel Shift

Hemorrhage CT Scan CT Scan You DO NOT need to angiographically visualize extravasation to have bleeding. 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

“Corkscrew” Carotid “Corkscrew” Carotid Stay Away!!

Trouble …for sure!

Judgement!! Backing out is OK Causing a Stroke is Not Roubin

Catheter skills + Anatomic Knowledge = Better results Conclusion…