Week 8- Aneurysms,
SAH, Dissections and
Arteritis
Week 8- Aneurysms, SAH,
Dissections and Arteritis

Week 8 Objectives









Define Brain Aneurysm
Define Pseudoaneurysms
Recognize different types of aneurysm radiographically
Be familiar with the angiographic evaluation of patients with
cerebral aneurysms
Be familiar with the angiographic evaluation of patients with
subarachnoid hemorrhage (SAH)
Identify methods of surgical treatment of aneurysms
Discuss aneurysm coiling
Perform basic set-up for Aneurysm coiling
Discuss the treatment of wide-necked aneurysm
Discuss the balloon remodeling technique
What Is An Aneurysm?
A cerebral aneurysm is a
bubble like outpouching
from an artery which
predisposes its carrier to
cerebral hemorrhage and
stroke
Images © Frank H. Netter, CIBA Collection of Medical Illustrations
History



1927
Moniz - angiography
1937
Dandy describes the clipping of
intracranial aneurysm
1949
Robertson described post-mortem
lesions after aneurysmal SAH.


Brain 72:150, 1949
1951
Ecker & Reimenschneider
angiographic spasm
Aneurysm Demographics






Aneurysms are found in 2-5% of the population
More likely to occur in adults age 40-60
There are as many as 27,000 aneurysms that could be
diagnosed and treated per year in the U.S.
They are more common in women (Sharon Stone had an
aneurysm that was treated with coils by an interventional
neuroradiologist)
The annual rupture rate is approximately 1.5%
Rupture of an aneurysm results in approximately 50%
mortality and 25% stroke incidence
Aneurysm Facts

Factors believed to contribute to
brain aneurysms:
Smoking
 Hypertension
 Traumatic head injury
 Alcohol use
 Use of oral contraception
 Post menopausal women > Men
 Family history of brain aneurysms
 Other inherited disorders: Ehler’s syndrome,
polycystic kidney disease, and Marfan syndrome

Aneurysm Facts

Symptoms of ruptured aneurysms:
 The worst headache of your life
Localized and intense headache
 Nausea and vomiting
 Stiff neck or neck pain
 Blurred or double vision
 Pain above and behind eye
 Dilated pupils
 Sensitivity to light
 Loss of sensation

The Configuration of Aneurysms

Aneurysms can be categorized by their configuration. There are
three basic distinctions between aneurysms. They are as follows:



Fusiform Aneurysms – Whole vessel circumference involved
Saccular Aneurysms – The lesion is eccentric.
Pseudoaneurysms - Occur when the layers or wall has been
perforated and the rupture is contained by an extraluminal
hematoma.
Terminology Associated With
Cerebral Aneurysms

Ectasia is a mild dilatation of a segment of vessel but is not
considered to be an aneurysm at this point.

Dissection is occurs when a tear in the lining of the artery
occurs and blood flows in between layers of the blood vessel.

Arteritis is inflammation of the cerebral arteries that obstructs
and occludes them.

Infundibulum is a funnel-shaped origin of a branch vessel.
Classifications of Aneurysms

Aneurysms of the Neurovascular system can
also be classified into 4 main groupings.

The groupings are as follows:
Extradural Aneurysms
 Pseudoaneurysms
 Intradural Aneurysms
 Giant Aneurysms

Classifications of Aneurysms
Extradural Aneurysms

Extradural Aneurysms occur outside of the
Dura Mater and are less likely to cause
subarachnoid hemorrhage.
Classifications of Aneurysms
True Vs. Pseudoaneurysms

Other terms you will also hear are True Aneurysms and False
(“pseudo”)Aneurysms

True Aneurysms are when the intima, media and advential layers are all intact.

False (Pseudoaneurysms) occur when the layers or wall has been perforated
and the rupture is contained by an extraluminal hematoma.

Causes of Pseudoaneurysm may include:





Trauma
Dissection
Surgical or Endovascular Interventional Injury
Biopsy
Adjacent Infection
Classifications of Aneurysms
Intradural Aneurysms

There are several categories of Intradural Aneurysms.
They are as follows:






Fusiform - (Associated with tortuosity, hypertension,
atherosclerosis and advancing age)
Mycotic and Inflammatory – (Caused by bacteria)
Oncotic – (Caused by metastasis)
Dissecting – (Caused by a disruption in the vessel walls)
Saccular (Berry) – (Develop over time and resemble a
“berry”)
DeNovo – (Caused by carotid occulsion or ligation)
Classifications of Aneurysms
Giant Aneurysms

Giant aneurysms are defined as aneurysms that
are 25 mm or larger in size.
Anatomy of an Aneurysm

A cerebral aneurysm (also called an intracranial aneurysm or
brain aneurysm) is a bulging, weakened area in the wall of an
artery in the brain, resulting in an abnormal widening or
ballooning. Because there is a weakened spot in the artery wall,
there is a risk for rupture (bursting) of the aneurysm.
A cerebral aneurysm generally occurs in an artery located in the
front part of the brain which supplies oxygen-rich blood to the
brain tissue. A normal artery wall is made up of three layers. The
aneurysm wall is thin and weak because of an abnormal loss or
absence of the muscular layer of the artery wall, leaving only two
layers.
The base is the “Neck and
the top is the “fundus “ or
“Dome"
Sites of Aneurysm Formation

The most common sites of Cerebral aneurysm
are:

The Circle of Willis

Branch Bifurcations
Sites of Aneurysm Formation
Anatomical distribution and relative incidence of Intracranial Aneurysms.
Left: Vessels of the circle of Willis showing multiple aneurysm
Right: Inferior view of brain showing subarachnoid hemorrha
Hemodynamic Properties of
Aneurysms

Aneurysms have the capacity to expand over
time.

The risk of rupture is related to the size of the
aneurysm

The tensile strength of an aneurysm is assumed
to decrease according to Laplace’s formula
which is as follows: P = 2 T/r
Hunt and Hess Scale
(Clinical Grading of SAH)
Grade
1
2
3
4
5
Description
Hunt and Hess Scale
Asymptomatic or minimal headache and slight nuchal rigidity
Moderate to severe headache, nuchal rigidity, no neurological
deficit other than cranial nerve palsy
Drowsiness, confusion, or mild focal deficit
Stupor, moderate to severe hemiparesis, possible early
decerebrate rigidity and vegetative disturbances
Deep coma, decerebrate rigidity, moribund appearance
Major Causes of SAH

Ruptured arterial aneurysm

Ruptured AVM

Perimesenchymal vein or capillary bleeding
95% of cases
Clinical Manifestations of SAH
Ruptured aneurysm
headache
stiff neck
focal deficit
Ribeiro JA., et al, Acta Medica Portuguesa.
11(12):1085-90, 1998 Dec.
Subarachnoid Hemorrhage: Signs
and Symptoms

Decreased alertness, Confusion, or Irritability






Temporary
Persistent
Progressively worse to coma and death
Syncope
Mental Status Exam
Abnormal vital signs



Respiratory variation
Hypertension
Irregular heart rate
Warning or “Sentinel” Bleeds

Up to 50% of patients with SAH report a
distinct, severe headache in the days or
weeks before the index bleed

Milder symptoms

History of Headaches
J Neurosurgery 1987
Features of Misdiagnosed
Patients
JAMA. 2004;291:866
-8
Features of Misdiagnosed
Patients
JAMA. 2004;291:866
-8
Features of Misdiagnosed
Patients
JAMA. 2004;291:866
-8
Who Needs Imaging?





Occipital location
Worsens with Valsalva
Awakens from sleep
Associated with syncope, nausea, or sensory distortion.
Patients with a sudden acute-onset headache

Prospective studies report that 30% of patients complaining
of the “worst headache of their life” had positive findings on
CT.
Computed Tomography


Sensitive for blood

day of the bleed 95%

within 12 hours of symptom onset  as high as 98%.
Sensitivity drops when

symptoms are days in duration

amount of bleeding is small
study is difficult to interpret

 85%

Ruptured Ant CoA
aneurysm
SAH 20 ruptured right
PCA
Normal Circle of Willis 3-D CTA
Normal Circle of Willis 3-D CTA
3-D CTA
SAH 20
ruptured
ACA
aneurys
m
3-D CTA
SAH 20
ruptured
PCoA
aneurysm
Lumbar puncture and CSF Exam

LP whenever the CT or CTA is negative, equivocal, or
technically inadequate

Blood or red blood cells in the first 8 hrs.

Xanthochromia or an inflammatory reaction when CSF
exam delayed
Lumbar Puncture (LP)
SAH Survival Depends On…






Elimination of risk of rebleeding by treating
aneurysm (Aneurysm clipping or coiling)
Management of Vasospasm
Management of Intracranial Pressure (ICP)
Management of Hydrocephalus
Manangement of Other Complications
Management of Cardiac Issues
SAH Survival Depends On …
Management of Vasospasm
Vasospasm
Normal Caliber
SAH Survival Depends On …
Management of Vasospasm





Diagnosis
Hypervolemic-hypertensive therapy
Calcium channel blockers
Cerebral angioplasty
Intracisternal thrombolytic therapy
SAH Survival Depends On …
Management of Intracranial
Pressure
Major Cause of Death
ICP monitoring
Fluid restriction?
Raising head
Hypothermia
Hypocarbia
Barbiturate coma?
Ventriculostomy
Steroids?
Mannitol
Increased Intracranial
Pressure
The pressure exerted in the cranium by
its contents:the brain, blood and
cerebrospinal fluid.

Components of Cranial Vault
(ICP can cause herniation!!!)

Meninges




Brain


Brain tissue 80-88%
Blood


Dura
Arachnoid
Pia
Blood 2-11%
CSF

CSF 9-10%
Elevated ICP = Danger
Animated GIF taken from http://www.artie.com
Other Problems


Elevated ICP can also affect the perfusion of
the brain
Cerebral Perfusion Pressure (CPP) is measured
by taking the Mean Arterial Pressure (MAP) and
subtracting Intracranial Pressure (ICP)
What does this mean?


This shows that if the ICP goes up… and MAP
stays constant… then the CPP decreases.
This means the patient is not getting as much
blood flow to the brain.
Poor Outcomes

Having an elevated ICP is one of the most
damaging aspects of neurological trauma, and is
directly related to poor prognosis.
Normal Values



A normal ICP in an adult ranges from 0-15
mmHG
An ICP cannot surpass 40 without causing
harm.
Even values between 25-30 are considered fatal
if they are prolonged.
Causes of ICP?

An elevated ICP can be caused by many different
etiologies.








Traumatic Brain Injuries
Lyme Disease
Hydrocephalus
Brain Tumor
Severe Hypertension
Venous Sinus Thrombosis
Restricting Jugular Venous flow (i.e. C-collars)
Etc.
Monitoring of ICP

There are 4 main types of devices for
monitoring ICP




Intraventricular Catheters
Fiber optic Monitors
Subarachnoid Bolts
Epidural Monitors
Stages of ICP

Initial compensatory

Secondary compensatory

Final compensatory
ICP: Initial Compensatory
Displacement of the cerebral spinal fluid into the
spinal canal or into venous blood through the
arachnoid mater
Intercranial Pressure
Regulation

When BP increases, cerebral arterioles constrict;
when BP falls, cerebral arterioles dilate to
increase Cerebral Blood Flow (CBF)

Metabolic regulation: Low O2 and high CO2
cause vasodilation; CSF reabsorption and
decreased Cerebrospinal Fluid (CSF) production
ICP: Secondary Compensatory
Reduction of blood volume to the brain. This
stage alters cerebral metabolism and produces
brain tissue hypoxia and necrosis.
ICP: Final Compensatory
Displacement of brain tissue which is herniation
and often leads to death.
Clinical Manifestation of ICP







Alteration in LOC – arousal and awareness
Restlessness
Irritability
Confusion
Dec.Glasgow coma score – scale for evaluating the best
motor, verbal and eye opening response (score 3-15)
Changes in speech
Pupillary reaction – dilation of pupil ipsilateral to
lesion, sluggish to respond to light
Clinical Manifestations of ICP






Bradycardia
HA
Vomiting – not preceded by nausea
Double vision, ptosis of eyelid, inability to move
eye upward
Vital Sign changes – Inc.systolic pressurewidened pulse pressure
Seizures
SAH Survival Depends On …
Management of Rebleeding


Leading cause of death or morbidity during the first 2
weeks after SAH
Incidence:




4-10% in 24 hours
15-25% in 2 weeks
2-3% after 1 month for 10 years
Presents with sudden change in neurological status, new
headache and coma.
SAH Survival Depends On …
Management of Rebleeding




Aneurysmal Clipping
Endovascular Coiling
Hematoma Evacuation
Procoagulatants
Hematoma Evacuation
Hematoma Evacuation
Teaching Points





SAH is often misdiagnosed
CT is sensitive but not fool-proof
LP for patients with normal or equivocal CT
Early angiography and IR/ Neurosurgery eval to
facilitate intervention
Treat to prevent multisystem and neurological
complications of SAH.



Attend to the airway and BP
Monitor and Control ICP
Prevent Re-bleeding and Vasospasm
Treatments for Cerebral Aneurysms

Endovascular Coiling

Surgical Clipping
Aneurysm Therapy

Surgical clipping (approximately 60-65% in the
United States)

Endovascular coiling (approximately 30-35% in the
United States)

In certain countries such as Finland, Great Britain and
France, close to 90% of aneurysms are treated with
endovascular coiling

After the release of the ISAT results, the percentage of
aneurysm patients treated with coiling in England went
from 40% to 90%
International Subarachnoid
Aneurysm Trial (ISAT) of
neurosurgical clipping versus
endovascular coiling in 2143 patients
with ruptured intracranial
aneurysms: a randomized trial
The Lancet
Vol 360, October 26, 2002
ISAT

A recent large prospective study of 2143 patients with
ruptured aneurysms who could equally be treated with
clipping or coiling had to be prematurely stopped short
of planned enrollment of 2500 patients because the
coiled patients suffered significantly less death and
dependency as compared to clipped patients (6.9%
absolute difference, 22.6% relative difference) and it
would have been unethical to continue the study
ISAT Study


Patients with ruptured
intracranial aneurysms
Dependency or Death at 1
year


Neurosurgical Clipping 243/793
(30.6%)
Endovascular Coiling 190/801
(23.7%)
Lancet.
2002;360(9342):1267-74
Aneurysm Clipping





Done under general
anesthesia through a
craniotomy (hole in the
head)
The brain is gently
retracted in order to gain
visual access to the
aneurysm
A clip is placed at the neck
of the aneurysm
1 week in the hospital
1 month recovery
Right Cerebellar Aneurysm
Surgical Clipping - Step 1: Identify Vessels
at Risk
ACA
Optic nerve
Aneurysm exposed
ICA
& PCA and SCA
Oculomotor
nerve
are identified as
Aneurysm
vessels at risk.
MCA
Right Cerebellar Aneurysm
Surgical Clipping - Step 2: Measure Baseline
Flows
Basilar a
Flowprobe
Baseline SCA & PCA
flows are measured
SCA
SCA = 18 cc/min
PCA = 36 cc/min
Aneurysm
PCA
Right Cerebellar Aneurysm
Surgical Clipping - Step 3: Clip and Remeasure
Positioning of Clip
Temporary Clip
Flow Integrity
Checked
SCA = 2-4 cc/min
PCA = 55-60 cc/min
Right Cerebellar Aneurysm
Surgical Clipping - Step 4: Check Flow
Integrity Post-Clip
Clip Repositioned
Flow Integrity
Checked
SCA = 16 cc/min
PCA = 33 cc/min
Clip Repositioned
Where is the aneurysm?
SAH
Where is the aneurysm?
Surgical clip
Before
After
Clips
ANEURYSM
COILING




A minimally invasive procedure usually performed
under general anesthesia by an interventional
neuroradiologist
A very small plastic tube (microcatheter) is threaded
from the groin to the aneurysm in the brain, and
fine platinum threads (coils) are inserted into the
aneurysm to fill it from the inside, much like filling a
pothole
The catheter is then removed and the small groin
incision covered with a Band-Aid
For an unruptured aneurysm, the patient is
discharged home within 24 to 48 hours
The History of Coiling





1987-1989: Dr. Guido Guglielmi
(University of Rome) visits Dr Viñuela
(Interventional Neuroradiologist) at
UCLA and research work on coiling
concept starts
1989: Dr Guglielmi comes
permanently to UCLA
1989-1990: Bench and animal research
March 6, 1990: First clinical use of
Guglielmi Detachable Coil
FDA approval in 1995
Imaging of the Aneurysm

Non-invasive imaging (CT) has already been done. The
Physician probably has a good idea where the aneurysm
is located prior to angiography.

A diagnostic angiogram is performed and the aneurysm
is localized.

A 3-D rotational spin can be performed while on the
patient is still on the procedure table prior to coiling the
aneurysm.
Rotational/3D Angiogram
Rotational/3D Angiogram

The above image can then be transferred to
another computer which will take the acquired
images and information and transform it into a
3-D image, as pictured below.
Rotational/3D Angiogram

Measurements of the aneurysms can be
obtained from these 3-D images.
Procedure Set-Up

As you will note, the beginning set-up is the
same for all interventional cases.

The following slides will review the following:
Pressure Bag Set-up
 Sheath or Guide Catheter positioning

Pressure Line Set-Up
Don’t Forget To Label Both Ends!
Tuohy-Borst Adapter
Three-Way Stopcock
Before Screwing to Sheath or Guide
Catheter…




Carefully Flush
Check for bubbles
Hook to Pressure Bag Line
Check and Re-Check for Bubbles
The Flow of things…the Pressure
Bag

Most times the pressure bags are even done
ahead of time due to the non-invasive studies
already done prior to angiography.
The Flow of things…Placement of
the Catheter, Shuttle Sheath or Guide
Catheter

Depending on the Physician and the situation, the Physician may
either leave the diagnostic catheter in place or exchange for
either the Shuttle Sheath or Guide Cath.

If the diagnostic catheter is left in a microcatheter is selected and
placed inside the diagnostic catheter.

If either a Guiding Catheter or Shuttle Sheath is chosen, they
are placed in the Common Carotid and the
diagnostic/microcatheter combo is reinserted after being
properly flushed with saline.
The Flow of Things…The Shuttle
Sheath
The Shuttle Sheath is a
long (usually 90 cm) sheath
used to engage the Common
Carotid artery.

It provides stiffness and
stability when coiling.
The Pressure Bag line is attached
to the sideport of the Shuttle Sheath
MicroCatheters

This is one of several types of microcatheters
(there are also microwires used with the
microcatheters).

They are ideally positioned directly within the
aneurysm sac where the coils will be delivered.
Roadmapping and Steering of
Coaxial System




Use of Bi-plane fluoroscopy
Use of Roadmapping feature may be helpful
Advance system carefully (Intracranial arteries
are thinner than peripheral arteries- less media
and adventitia)
Hand injections should be done carefully so as
not to rupture any perforators.
Roadmap During Coiling
The Flow of Things…Aneurysm
Coiling

Once the aneurysm is identified and
analyzed,the microcatheter is placed within the
aneurysm and the coiling process is started.

Follow-up DSA runs are periodically acquired to
check the progression of the coiling
The Coiling Process
The Flow of Things…Aneurysm
Coiling

The coiling process will probably last for several
hours, so one thing to consider, does the patient
have or require a Foley catheter?

Another note about the drugs. During the
coiling process, it’s a good idea to have
Protamine Sulfate readily available in case of
aneurysm perforation and the need to reverse
Heparin.
GDC Coil Detachment Device
Cable Attachment
Black and Red Cables
are placed in the
corresponding holes of the
detachment mechanism
Coil Preparation
An Aneurysm Coiling Seen Step-ByStep

The next several slides will demonstrate an
Aneurysm Coiling step-by-step.
SAH
Rupture of an
aneurysm at the tip of
the basilar artery
Tip of Ventriculostomy
before
after
Pros and Cons of Coiling
PROS




Minimally invasive
Short recovery
Safer than surgery
Cheaper than surgery
CONS



Shorter track record
Possibly less durable
Requirement for followup angiography
The Future

Increased percentage of patients treated with coiling, in large
volume referral centers

Use of adjunctive maneuvers increases the percentage of
aneurysms treatable with endovascular techniques

Increased efficacy of coiling therapy (new, bioactive materials,
tissue healing strategies)

Development of non-invasive follow-up techniques with CT or
MR scanning

Better educated population will actually demand availability and
discussion of both endovascular coiling and surgical clipping
options
What about Aneurysms with Wide
Necks?

Aneurysms with wide necks must be treated in a
slightly different manner.

The use of a Neuroform stent or some similar
stent must first be placed across the base or neck
of the aneurysm. This is done so that the coils
will remain within the aneurysm sac.
Wide neck mid basilar aneurysm
Stent + Coil
Wide-Neck Aneurysm Coiling with
Stent Assistance
Stent + coils
Balloon Remodeling

Balloon remodeling is the use of a balloon while
placing coils within the aneurysm.

The balloon is inflated while the coil is placed
and then deflated once coil is in place.
Onyx is another possible choice to
treat aneurysms
Take Home Points

The ISAT study recently demonstrated a
substantially better clinical outcome (22.6% less
death and dependency relative difference, 6.9%
absolute difference) in patients with ruptured
aneurysms treated with endovascular coiling
compared to patients treated with surgical clipping
Take Home Points

All patients with aneurysms should be informed
of the availability of both endovascular coiling
and surgical clipping by a neurosurgeon and an
interventional neuroradiologist

The death and complication rate for aneurysm
therapy is dramatically reduced in high volume
centers that offer both surgical clipping and
endovascular coiling
Information and Links
American Society of Interventional and
Therapeutic Neuroradiology (ASITN)
http://www.asitn.org/
Homework Assignments

Read Chapter 16 (pp. 311-347)and Chapter 25
(pp. 467-481)
References






Morris, P.P. Practical Neuroradiography, 2nd Edition, 2007
Osborn, A.G. Handbook of Neuroradiology, 2nd Edition,
1999
Bontrager, K.L. TEXTBOOK of Radiographic Positioning
and Related Anatomy , 5th Edition, 2001
Snopek, A.M Fundamentals of Special Radiographic
Procedures, 5th Edition, 2006
Tortorici, M.R. Fundamentals of Angiography, 1982
Various other Internet sources