Carotid artery stenosis refers to a 50% or greater blockage of the carotid arteries, which supply blood to the brain. The document discusses the anatomy of the carotid arteries and risk factors for ischemic stroke such as atherosclerosis. For asymptomatic patients, screening with carotid duplex ultrasound may be considered for those with multiple cardiovascular risk factors. Medical management including statins, blood pressure control, and aspirin can significantly reduce stroke risk. For high-risk asymptomatic patients, carotid endarterectomy or stenting may be options. Symptomatic patients with greater than 50% stenosis are generally treated with carotid revascularization, especially if additional risk factors are present.

1. CAROTID ARTERY STENOSIS
Dr Pankaj S Rathi

2. Definition
Carotid artery stenosis refers to a ≥ 50%
stenosis of the extracranial internal carotid
artery (ICA), with stenosis severity
estimated using the North American
Symptomatic Carotid Endarterectomy Trial
(NASCET) method.

3. Carotid Artery Anatomy

4. Internal Carotid Artery
It arises most
frequently between C3
and C5 vertebral level,
where the common
carotid bifurcates to
form the internal
carotid and
the external carotid
artery (ECA)

5. Anatomical variations and segments of
ICA
• Variations in level of
bifurcation
– left higher 50%
– right higher 22%
– same height 28%
• Variations in origin
C1/2: 0.3%
C2/3: 3.7%
C3/4: 34.2%
C4/5: 48.1%
C5/6: 13%
C6/7: 0.15%
ICA Segments
Bouthillier Classification
• cervical segment
• petrous (horizontal)
segment
• lacerum segment
• cavernous segment
• clinoid segment
• ophthalmic (supraclinoid)
segment
• communicating (terminal)
segment

8. Indian figures of Ischemic stroke
• Prevalence rate : 545 per 100,000
• Mortality rate in stroke is 7.5 per 1000
• Carotid stenosis is an established risk factor of
ischemic stroke
• Atherosclerosis of internal carotid artery (ICA) is a
major risk factors for stroke
• Causative factor in approximately 30% of all
ischemic strokes
Ann Indian Acad Neurology 2015 Oct-Dec; 18(4): 412–414
Neurology India : 2017, Vol 65 Issue 2 Page : 279-285

9. Severity of The Problem in India
• Asymptomatic carotid artery stenosis (ACAS) of
more than 50% has a 2–6% annual risk of stroke
• 5.2% of asymptomatic individuals > 40 years of
age harbor significant extracranial carotid artery
disease
Neurology India : 2017, Vol 65 Issue 2 Page : 279-285

10. Prevalence and features of carotid
atherosclerosis
Neurology India : 2017, Vol 65 Issue 2 Page : 279-285

11. Natural History of Atherosclerotic
Carotid Artery Disease
• Extracranial atherosclerotic disease accounts for up to
15% to 20% of all ischemic strokes
• Clear correlation between the degree of stenosis and the
risk of stroke in the NASCET study
After 18 months of medical therapy without
revascularization
Risk of stroke rates
19% in those with 70% to 79% initial stenosis,
28% in those with 80% to 89% stenosis
33% in the 90% to 99% stenosis
Risk diminished with near-occlusion
Circulation. 2011;124:e54-e130

13. Characterization of Atherosclerotic Lesions
in the Extracranial Carotid Arteries and
stroke
Plaque morphology
Ulceration, echolucency, intraplaque hemorrhage,
and high lipid content
Hypoechoic plaques
Subcortical and cortical cerebral infarcts of
suspected embolic origin
Hyperechoic plaques
Diffuse white matter infarcts of presumed
hemodynamic origin

14. Methods of Diagnosing Carotid Artery
Stenosis
• Carotid Duplex Doppler
• CT Angiography
• MR Angiography
• DSA

15. Indications for carotid duplex
sonography
• Cervical bruit in an asymptomatic patient
• Follow-up of known stenosis (50%) in asymptomatic
individuals
• Vascular assessment in a patient with multiple risk
factors for atherosclerosis
• Stroke risk assessment in a patient with CAD or PAD
• Amaurosis fugax
• Hemispheric TIA
• Stroke in a candidate for carotid revascularization
• Follow-up after a carotid revascularization procedure
• Intraoperative assessment during CEA or stenting

16. Grading Of ICA Stenosis

17. Method of Grading

18. Asymptomatic & Symptomatic Carotid
Artery Disease
• Asymptomatic carotid stenosis
If patients lack a recent history (6 months) of ipsilateral carotid
ischemic stroke or transient ischemic attack .
• Symptomatic carotid stenosis
Stenosis in the internal carotid artery, either intracranial or
extracranial, leading to symptoms of amaurosis fugax, transient
ischemic attacks, or ischemic stroke ipsilateral to the lesion
• Severe stenosis (70–99%) :
Highest risk for recurrent stroke or TIA
Stroke. 2017;48:00-00
Curr Treat Options Cardio Med (2017) 19: 62

19. Indications for Screening Carotid
Artery

21. Our Patient
• Mr. X is a 74 year old man
• On a statin for elevated cholesterol and ASA for
primary prevention
• Has attended 3-4 health check up over past 7
years to request carotid artery screening
• Was told of 50% stenosis
• Worried about risk for stroke
• Would consider procedure to open artery if
would reduce risk of stroke

22. Past Medical and Surgical History
• Elevated cholesterol
• Low back pain
• Cervical spondylosis
• GERD
• BPH
• S/p shoulder surgery

23. Social and Family History
• Retired medical officer
• Travels twice yearly from Indore to Jabalpur
with wife
• Helps to care for 4 grandchildren
• No cigarettes
• Social alcohol use, 2-3 glasses whisky/week
• Family history: no cardiovascular disease or
stroke

24. Medication History
• Simvastatin 20 mg qd
• Aspirin 81 mg qd
• Omeprazole 20 mg qd
• Tamsulosin 0.8 mg qhs

25. Health Examination
• Well appearing
• Bp 124/82, HR 72, weight 72, BMI 26.7
• Chest - clear
• Cardiac – RRR no murmurs or S4
• Extremities - normal

26. Would you screen this patient for
carotid artery stenosis?

27. Evaluation of Asymptomatic Patients
at Risk of Extracranial Carotid Artery
Disease
Recommendations for Duplex Ultrasonography
to Evaluate Asymptomatic Patients With
Known or Suspected Carotid Stenosis
Circulation. 2011;124:e54-e130

29. Duplex ultrasonography to detect
hemodynamically significant carotid stenosis may
be considered in asymptomatic patients with
symptomatic PAD, coronary artery disease (CAD),
or atherosclerotic aortic aneurysm
Circulation. 2011;124:e54-e130
I IIaIIb III

30. Duplex ultrasonography might be considered to detect carotid stenosis in
asymptomatic patients without clinical evidence of atherosclerosis who
have 2 or more of the following risk factors: hypertension, hyperlipidemia,
tobacco smoking, a family history in a first degree relative of
atherosclerosis manifested before age 60 years, or a family history of
ischemic stroke. However, it is unclear whether establishing a diagnosis of
ECVD would justify actions that affect clinical outcomes.
Circulation. 2011;124:e54-e130
I IIa IIb III

32. In a metaanalysis, DUS, MRA and CTA were
equivalent for detecting significant carotid
stenosis
Accurate, practical and cost-effective assessment of carotid stenosis in
the UK. Health Technol Assess 2006;10:iii–iv, ix–x, 1 - 182.

33. Decision making in management of
carotid artery stenosis

35. Asymptomatic Carotid Stenosis:
What is Medical Intervention,
and Is It Effective?

36. Best Medical Therapy in Carotid
Stenosis
Best medical therapy (BMT) includes CV risk factor
management, including best pharmacological therapy, as
well as nonpharmacological measures such as smoking
cessation, healthy diet, weight loss and regular physical
exercise.
Pharmacological component
Antihypertensive
Lipid-lowering
Antithrombotic drugs
Optimal glucose level control
Eur Heart J 2007;28:2375–2414

37. Moving targets
Carotid stenting has evolved.
Outcomes are improving and the
procedure is maturing. Randomized
trials (including CREST) now
supported by large post-market
surveillance outcomes
Medical therapy has also evolved with
evidence suggesting the risk of stroke in
asymptomatic patients today may be
much lower than even 10 years ago

38. ASA
Early
1900s
Late
1900s
Today
ASA
HTN RX
1800s
ASA
HTN RX (ACEI,
beta blockers)
DM Control,
Lipid Rx
ASA
HTN RX
Tight DM Control
High dose statins
ACE and ARB

39. Annual TIA and stroke in asymptomatic
control arms of selected randomized trials
0%
2%
4%
6%
8%
10%
12%
14%
16%
18%
20%
Ipsilateral stroke/ TIA
Ipsilateral stroke/ TIA

40. Effect of Antiplatelet Therapy in
Patients with TIA or Stroke
Antiplatelet Trialists’ Collaboration. BMJ 2002;324:71-86
287 Studies: 135,000 Patients in Comparisons of
Antiplatelet Rx vs Control

43. Use of ramipril in preventing stroke:
double blind randomised trial
BMJ VOLUME 324 23 MARCH 2002 bmj.com

44. Stroke 2009;40
• 1007 patients with carotid stenosis
(not requiring revascularization) at baseline
– 3271 patients had no carotid stenosis at baseline
• All patients had stroke/TIA within 6 months of
randomization
– Randomized to Atorvastatin 80 mg/d vs Placebo
• No known CHD
• LDL Cholesterol between 100-190 mg/dL

45. Of those patients with carotid artery stenosis at
baseline…
• Atorvastatin lowered any stroke risk by 33%
• Atorvastatin lowered any CHD event by 43%
• Later carotid revascularization was reduced by
56%!

46. The Carotid “Prescription”
• ASA 81 mg/d
– No role for dual antiplatelet therapy for stroke
“prevention”
• Antihypertensive Therapy
– ACE Inhibitor
– Angiotensin Receptor Antagonist
• Lipid Lowering Therapy
– LDL-Cholesterol <100 mg/dL
• Tobacco Cessation
• Glycemic Control (HbA1C <7.0%)

48. Asymptomatic Carotid stenosis
with High Risk Factors

50. Asymptomatic Carotid Stenosis with
High Risk Factors

51. When Invasive Procedure ?

52. Treatment for Asymptomatic Carotid
Artery Stenosis with high risk factors
Revascularization
 Carotid endarterectomy
(CEA)
 Carotid artery stenting
(CAS)

53. Carotid endarterectomy (CEA)

54. Carotid artery stenting (CAS)

55. Endovascular techniques
Carotid Artery Stenting
Less invasive
Low risk of cranial nerve
injury,
Wound complications
Neck haematoma
Carotid Endarterectomy
CAS offers advantages
‘hostile neck’ (previous
radiation, recurrent
stenosis), contralateral
recurrent laryngeal nerve
palsy or in the case of
challenging surgical access
[very high ICA lesions,
proximal common carotid
artery (CCA) lesion

57. CREST (Carotid Revascularization Endarterectomy versus Stenting Trial),
SAPPHIRE (Stenting and Angioplasty with Protection in Patients at High Risk
for Endarterectomy) ACT trial ( Asymptomatic Carotid Trail )

60. ACST 10-year Follow-up Results Provide Most Rigorous Comparison Of revascularization
And BMT Lancet. 2010 Sep 25; 376(9746): 1074–1084

61. Symptomatic Carotid Artery Disease

62. Symptomatic Carotid Artery Disease

63. High Risk Features for CEA & CAS

67. Failure of Medical Therapy in
Symptomatic Carotid Artery Disease
• 50–99% stenosis if
treated medically
• Increasing age (>75
years)
• Symptoms within 14 days
& Male sex
• Hemispheric symptoms
• Cortical stroke
• Medical comorbidities
• Irregular stenosis
• Increasing stenosis
severity
• Contralateral occlusion

68. Timing of CEA

69. P.M. Rothwell et al. Stroke. 2004;35:2855-2861
Copyright © American Heart Association, Inc. All rights reserved.

70. Timing of CEA
CEA within 14 days ( 50–69% )
ARR for stroke at 5 years ( 14.8% NNT = 7)
ARR (3.3% NNT = 30)when delay was 2–4 weeks
ARR (2.5% NNT 40 ) when the delay was 4–12weeks
Beyond 12weeks, no strokes were prevented by CEA.
CEA within 14 days ( 70–99%)
ARR for stroke at 5 years was 23.0% (NNT = 4)
ARR (15.9% NNT 6 ) where delays were 2–4weeks
ARR (7.9% NNT 13 ) for delays of 4–12weeks
ARR (7.4 % NNT 14 ) at 5 yrs when done beyond
12weeks

71. Endovascular therapy vs. open surgery
• The risk of ‘any stroke’ and ‘death/ stroke’ was 50% higher
following CAS, primarily because CAS was associated with
a significantly higher rate of minor stroke
• CAS was associated with higher periprocedural
death/stroke, especially in patients >70 years of age, but
with significantly lower risks for MI, cranial nerve injury
and haematoma

72. Conclusion
• CEA and CAS should largely be used for symptomatic
patients
• Most asymptomatic patients should get best medical
treatment ( BMT ) & neither CAS or CAS ( except for small
% )
• Except in extraordinary circumstances, carotid
revascularization by either CEA or CAS is not
recommended when atherosclerosis narrows the lumen by
less than 50%
• Carotid revascularization is not recommended for patients
with chronic total occlusion of the targeted carotid artery
• Carotid revascularization is not recommended for patients
with severe disability caused by cerebral infarction that
precludes preservation of useful function

73. THANK YOU