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DR. Ahmed Abanamy Hospital
DOCTOR
Nazih Mohammed Alothman
Vascular Surgeon
ATHEROSCLEROSIS
OF
CAROTID ARTERY
Introduction
Stroke is the primary cause of disability and
third most common cause of death in U.S.A .
Atherosclerosis occlusive disease of extra cranial
carotid artery is a major risk for stroke ,which
accounts 90% of lesion in extra cranial system.
Atheromatous lesions characteristically occur at
branches of arterial bifurcations .
Common sites include
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The point of take-off branches of the aortic arch.
The origin of vertebral artery .
The bifurcation of common carotid artery .
The carotid siphon .
The origins of anterior &middle cerebral artery ACA-MCA.
Extra cranial : intracranial lesions = 2:1
differential diagnosis
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Fibro muscular dysplasia
Arterial kinking as result of elongations
Extrinsic compression
Traumatic occlusion
Intimal dissection
Inflammatory angiopathy
Migraine
Radiation
Other rare entities :
fibrinoid necrosis -amyloidosis - allergic
angiitis .
pathology
Tow theories emerged as
explanation for TIA
The arterial stenosis theory
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Crawford and Coworkers stated that
the criterion for carotid
endarterectomy should be the
presence of pressure gradient across
stenosis which decreased flow.
TIA may result from intermittent
episode of systemic hypotension or
decreased cardiac output in patient
with stenosed or occluded cerebral
arteries .
The cerebral emboli theory
The fact that Atheromatous
plaques
can be a source of emboli was
first
reported by Ponum in 1862 .
Ulcerated plaque at carotid bifurcation can releases emboli ,
where they pass retrograde via collateral communication to
ophthalmic artery then to carotid siphon and into MCA .
Emboli can reach hemisphere ipsilateral to an internal
carotid artery occlusion from opposite carotid artery or from
the vertebral-basilar system .
One variant of posterior circulation ischemia occur with
subclavian steal syndrome .
Intra cerebral thrombosis is caused by intra cranial
atheromatosis or by thrombus from the internal carotid artery
distal to proximal Atheromatous stenosis .
Sudden intra plaque hemorrhage produced an acute
occlusion .
Diagnosis
ULTRASOUND
Carotid duplex
Trans cranial
Doppler (TCD)
Carotid duplex
with B mode imaging is important to:
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determine whether the patient is a candidate for
carotid endarterectomy .
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detect and characterize atherombotic plaque
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measure intima ,midia thickness .
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level of stenosis
(mild :<50% , moderate :50-69% , sever :7O-99% ,
occluded :100% ) .
it cannot differences between 99% stenosis and occlusion
Trans cranial Doppler (TCD)
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provide additional
information on flow
dynamics presence or
absence of collateral
circulation and
central vascular reserve
detect emboli in MCA .
ANGIOGRAPHY
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Has a combined mortality and morbidity of 0.5-4% in patient
with atherosclerosis .
Cerebral angiography is the most complete preoperative study
for anatomic delineation of the carotid arteries and their
intracranial branches.
In the patient considered a candidate for carotid
endarterectomy, a full angiographic examination includes
bilateral visualization of the extra cranial arteries, evaluation of
# hemispheric blood flow
# and aortic arch imaging
# Selective views are added to aid in the diagnosis of ulcerative
lesions
# additional information on the vertebrobasilar system
# rule out other causes of neurologic symptoms, such as siphon
and branch stenoses, cerebral aneurysms, tumors, and
arteriovenous malformation.
MR IMAGINGRAPHY
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Still has limitation due to overestimation of
degree of stenosis and production of flow
artifacts .
Combination of both MR imaging and
carotid duplex can provide accurate
diagnosis of carotid stenosis and plaque size
no invasively .
Management
Medical therapy
No drug therapy has been shown to reduce the risk of stroke in
patient with asymptomatic carotid disease .
Medical management in symptomatic patient is focused on
antiplatelet agent .
Aspirin is affective in reducing stroke and stroke related death
Low doses (80 mg per day )are as efficacious as higher doses
(1,200 mg per day ) .
Other antiplatelet agent such as (dipyridamol –ticlopidine)
are no better than aspirin alone .
Anticoagulation with heparin sodium is beneficial in patient
who have cardiac emboli and in evolving stroke to prevents
progression of thrombus .
There is reduction in stroke risk for patient with 50-99%
intracranial stenosis on warfarin compared to aspirin .
Surgical therapy
indication for
surgical repair
Asymptomatic carotid stenosis > 75%
The risk of stroke is 3-5%per year .
Operative mortality and morbidity rate is 3%
And The average late stroke is 0.3% per year .
Asymptomatic carotid stenosis with ulceration
Ulcers has been divided into
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A ulcer : <10mm2 –no surgery .
B ulcer : 10-49mm2 –depend on the experience of
surgical team and importance of lesion .
C ulcer : > 40 mm2 .
cavernous
compound
surgical reaper (the stroke rate is 7.5% per year) .
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Symptomatic patient with >70 % stenosis
Symptomatic patient with >50 % stenosis
Who has an ulcerated or symptoms persist while
they are on aspirin .
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Selected patient with stroke in evolution
Mild to moderate neurological defect and no
hemorrhage on CT .
the time of surgery is controversial .
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Selected patient with complete stroke
the candidation of surgery:
- >70% stenosis .
- >50% stenosis and ulcer .
- <70% stenosis and contra lateral occluded carotid
artery
the time of operation is 4-6 weeks later to minimize
the risk of postoperative hemorrhage .
rarely in acute patient with completely occluded
carotid artery
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Who has undergone endarterectomy and develop
immediate postoperative thrombosis or symptoms .
Asymptomatic patient and has had a bruit
disappear while under observation or progressive
symptoms .
symptomatic patient and has a new internal carotid
occlusion that can be operated within 2-4 hours of
onset of symptoms .
CONTRAINDICATION TO SURGERY
1.
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4.
Serious illness .
Major stroke and not yet began to recover
Major stroke in the past and is so divested
by neurological dysfunction or altered
consciousness that operation is advisable .
Acute stroke .
operation technique
Local
anesthesia
SURGERY OF CAROTID
BIFURCATION
Allow the surgeon to evaluate the patient's cerebral
tolerance to carotid clamping .
Disadvantages relate to anxiety , restless and agitation of
patient and extended operation .
General
anesthesia
Control of patient's airway and ventilator .
 Halogenated agents can increase cerebral blood
flow decrease cerebral metabolic .
 Comfortably surgical team without disturbing the
operation field .
position
supine ,with neck slightly hyper
extended , and gently turned to side
opposite that of operation.
flexing the operation table 10-20 degree
incision
vertical incision
It parallels the carotid artery
 Extension of incision is simple and
easy
oblique incision
More acceptable scar
It necessary to raise skin flaps
More difficult to gain additional
exposure
Carotid sheathe is incised low on the
neck
Common facial vein is landmark for
carotid bifurcation .
1-2 ml of 1% lidocain may be injected into the tissue
between the external and internal carotid arteries to block
the nerves to carotid sinus .
We must preserve : The superior thyroid artery , and
ascending pharyngeal artery , and 12th cranial nerve which
passed obliquely just superior to the bulb of the carotid a.
CAROTID CROSS-CLAMPING :
85-90% of patient have adequate cerebral collateral
circulation .
General anesthesia prefer to an internal artery shunt .
Complication of insert shunt :
- scuffing and disruption intima .
- introduction of air or thrombolic emboli .
Patient without shunt has a post operation neurological
complication rate 1.5% , whereas those with shunt 5%.
MONITORING PATIENT UNDER
GENERAL ESTHESIA :
1.
Measurement of ipsilateral jugular
venous oxygenation .
2.
Electroencephalography .
3.
Back-flow from internal carotid
artery .
4.
Internal carotid back-flow pressure
(>25mmhg
Complications of Carotid Endarterectomy
Hematoma
Infection
Carotid artery Disruption
False aneurysm
Carotid-cavernous
arteriovenous fistula
Graft infection
Cranial nerve injury
Embolism
Cerebral ischemia
Postoperative period
Stroke
Thrombosis of endarterectomized segment
Hypotension
Hypertension
Myocardial infarction
Recurrent stenosis
thanks
DR . nazih Mohammed al -othman