2. INTRODUCTION
Stroke is the fourth leading cause of death and the number one cause of long-term severe
disability in the worldwide.
Carotid stenosis (CS) is an important cause of ischemic stroke accounting for 20 to 25%.
Previous studies have established the benefits of carotid endarterectomy (CEA) compared
with best medical therapy (BMT).
More recently, carotid artery stenting (CAS) has emerged as an alternative to CEA.
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3. PATIENT SELECTION
Prior to any procedure, the interventional cardiologists should perform a consultation
including a tailored history and physical examination along with review of any available
imaging and laboratory tests.
Briefly, symptomatic patients (neurological event within the preceding 6 months) with > 50%
CS and asymptomatic patients with >70 % CS are candidates for carotid revascularization.
Choice between CEA and CAS will depend on patient factors, operator preference
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4. Approximately 20 years ago, several RCTs compared medical therapy with CEA for both symptomatic
and asymptomatic patients.
CEA was superior to medical therapy (primarily aspirin) for stroke prevention.
As less-invasive revascularization techniques with stents evolved and became more successful, pivotal
trials were performed to obtain FDA approval, and head-to-head comparisons with CEA were performed.
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5. CLINICAL TRIALS
The SAPPHIRE (Stenting and Angioplasty With Protection In Patients at High Risk for Endarterectomy)
trial found no difference in 1-year stroke, death, and myocardial infarction (MI) in symptomatic
patients,
but CAS had a better outcome in asymptomatic patients (9.9% vs. 21.5%; p = 0.02) compared with
CEA.
At 1 year, significantly more CEA patients required repeat revascularization (4.3%vs. 0.6%, p = 0.04)
than CAS patients. At 3 years, there was no difference for major adverse cardiac events, death, or
stroke.
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6. CLINICAL TRIALS
For average-surgical-risk patients, CREST (Carotid Revascularization Endarterectomy Versus Stenting
Trial) randomized 2,502 symptomatic and asymptomatic patients and found no difference between
CAS and CEA for the combined endpoint of stroke, death, and MI or the rate of post-procedural
ipsilateral stroke after 10 years of follow-up.
In the CEA group, there was an excess of perioperative heart attacks, which was associated with a 3.5-
fold increased risk of death (hazard ratio [HR] 0.50 [0.26-0.94]; p = 0.03) at 4 years.
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7. CLINICAL TRIALS
The clinical equipoise for CAS and CEA demonstrated in CREST was recently confirmed by ICSS
(International Carotid Stenting Study), a large multicenter, international RCT involving 1,710 patients with
symptomatic carotid artery stenosis.
The primary endpoint, the cumulative 5-year risk of fatal or disabling strokes, did not differ between
CAS and CEA (6.4% vs. 6.5%; HR 1.06 [0.72-1.57], p = 0.77).
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8. CLINICAL TRIALS
For asymptomatic patients undergoing revascularization to prevent stroke, ACT-1 (Asymptomatic
Carotid Trial) demonstrated clinical equipoise for CAS and CEA.
In 1,453 asymptomatic patients, the primary composite endpoint of death, stroke, or MI within 30
days of the procedure or ipsilateral stroke within 1 year was not inferior for CAS (3.8%) compared
with CEA (3.4%; p = 0.01 for noninferiority).
After 5 years of follow-up, the stroke-free survival was not different at 93.1% for CAS and 94.7%
for CEA (p = 0.44).
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9. THE 2011 ACC/AHA GUIDELINES FOR CAS
CAS was recommended as an alternative to CEA in average-surgical-risk
symptomatic patients when the anticipated risk of periprocedural stroke or
mortality is <6% (Class I, Level of Evidence [LOE] B)
They also preferred CAS to CEA when carotid lesions were anatomically
unfavorable (i.e., in cases of restenosis, high cervical or intrathoracic lesions, or
following radiation therapy) (Class IIa, LOE B).
Finally, they recommended that CAS may be considered in highly selected
asymptomatic patients with ≥60% angiographic stenosis (Class IIb, LOE B).
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13. The Center of Medicare and Medicaid Services (CMS) defines high
risk to include but not limited to the following comorbid
conditions:
congestive heart failure class III/IV, left ventricular ejection fraction < 30%,
Unstable angina,recent myocardial Infarction,
contralateral carotid occlusion
previous CEA with restenosis,
prior radiation treatment to the neck,
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15. PROCEURE ----PATIENT PREPARATION
Once the decision to perform CAS has been made, a detailed informed consent should be obtained.
Oral antiplatelet therapy with Clopidogrel should be initiated 5 days prior to treatment date.
If this is not practical, a loading dose of 300 mg of clopidogrel should be given 4 to 5 hours prior to
the procedure.
Routine prophylaxis for preexisting contrast allergy and/or renal insufficiency should be performed per
protocol.
Baseline neurological examination should be performed and documented.
Bilateral inguinal regions should be sterilely prepared for access
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16. DIAGNOSTIC ARTERIOGRAM
The right common femoral artery (CFA) is the preferred access for CAS. The left CFA and the
brachial artery are alternative accesses if the right CFA is not optimal.
Aortic arch aortography obtained at approximately 35 degrees left anterior oblique
projection should profile the origins of the great vessels.
This step may be skipped if recent, high-quality, noninvasive imaging of the cervical aortic
arch is available for reference.
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17. The aortic arch may be classified based on the
origins of the great vessels in reference to the
convexity of the aortic arch:
Type I—great vessel origins are level with upper
convexity;
Type II—great vessel origins are between the
upper and lower convexity.
Type III—great vessel origins are caudal to lower
convexity
DIAGNOSTIC ARTERIOGRAM
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Selection of great vessels in the
setting of Type III arch can present a challenge and typically
requires a reverse curve catheter (e.g., Simmons 2 or 3 )
19. DIAGNOSTIC ARTERIOGRAM
The CCA is selected and anterior-posterior and lateral projections of the
cervical carotid artery should be obtained.
Ipsilateral Oblique projections may be necessary to optimally visualize the
stenosis.
In some instances, a reference marker (e.g., 1-cm metallic sphere) may be
placed on the patient to allow accurate calibration for stenosis grading
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20. FOR STENOSIS ANALYSIS
North American Symptomatic Carotid Endarterectomy Trial (NASCET)
technique is recommended;
that is, the narrowest portion of the stenosis is referenced to the most normal
diameter immediately cephalad to the stenosis and not below.
If the stenosis fails to meet criteria, then the procedure is terminated and the
patient should be followed clinically and managed with BMT.
If the stenosis is confirmed, baseline ipsilateral cerebral angiography is
performed.
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22. CAROTID ARTERY STENTING
An exchange length guide-wire is placed with the tip in the distal CCA or in the external
carotid artery.
A sheath with sufficient length and diameter is placed (most commonly a 90-cm 6F sheath).
Intravenous anticoagulation is required and most operators prefer unfractionated heparin. A
bolus dose of 100 unit/ kg is administered and titrated to reach an activated clotting time
(ACT) of 250 to 300 seconds
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23. Once the sheath is in place and the desired ACT level is reached, anticipated equipment
should be prepped and readied for use on the sterile field, including the embolic protection
device (EPD), stent, angioplasty balloon, and recapture catheter.
Having the equipment ready will help to minimize the time duration of the deployed EPD.
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24. EMBOLIC PROTECTION DEVICE PLACEMENT
There are three general types of EPD:
• 1.distal occlusion balloon,
• 2.distal filter device, and
• 3. proximal flow diversion.
All these three types have advantages and disadvantages.
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26. DISTAL PROTECTION DEVICE (EPD)
most widely used and preferred one
an appropriately sized EPD (slightly larger than internal carotid diameter) should be selected
and placed.
Irrespective of the type, the EPD should be upsized approximately1 mm to provide optimal
embolic protection.
The EPD should be deployed in the straight terminal segment of the cervical carotid artery
with enough distance from the stenosis to allow sufficient space to deliver the stent.
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27. PRECAUTIONS WHILE DEPLOYING
Once deployed, adequate apposition to the carotid arterial wall needs to be ensured by angiography.
If the device is too small, emboli may not be captured, and if too large the EPD may cause arterial injury
or induce vasospasm.
Special attention should be given to minimize cranial–caudal motion of the EPD once deployed, as
excess motion may also lead to dissection or, more commonly, vasospasm
The major disadvantage of the distal protection devices is the lack of protection during the initial
engagement of the stenosis with the EPD delivery system prior to EPD deployment
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28. EPD Induced Spasm
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This degree of vasospasm
typically will resolve with time
without any consequence
Occurrence
of EPD-induced vasospasm
can be reduced by
appropriately sized EPD
and minimization of motion of
EPD during the carotid artery
stenting
29. PREDILATION ……?
Predilatation of the stenosis after the placement of the EPD and before stent deployment is
controversial.
The theoretical benefits include less traumatic stent delivery and reduced need for post
delivery dilation.
The potential disadvantages include the risk of distal embolization, potential for plaque
rupture without stent protection, and additional time requirements.
Should not be done , but it will permit delivery of the stent in cases where the stent cannot
be safely advanced.
If predilation is desired, a 2.5- or 3-mm diameter balloon should suffice.
In a native carotid artery (i.e., no previous CEA), prior to predilation 0.5 to 1 mg of atropine
may be given prophylactically or be ready for administration if bradycardia ensues.
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30. STENT PLACEMENT
Nitinol or Elgiloy-based self-expanding stents are used for CAS.
The stent length has to be sufficiently long enough to completely cover the stenosis, which in
most cases necessitates extending from it from the CCA to the ICA.
To achieve optimal wall apposition in all carotid segments, the stent diameter needs to match
that of the CCA.
The stent should be advanced slightly beyond the desired location distal to the stenosis and
retracted prior to deployment to reduce any slack or redundancy that may cause the stent to
jump forward.
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31. STENT PLACEMENT
If there is incomplete coverage of the stenosis, a second stent may need to be
place
Atropine should be given or be ready to give immediately in the event of
bradycardia.
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32. POST DILATION
After the stent is placed, post dilation may be required if the stent is not expanded adequately.
However, it is generally advised to avoid the temptation to over-dilate the stent or to make it look
“perfect.”.
Successful outcomes of CAS have been reported with intentional avoidance of routine post dilation
as stents have been observed to expand spontaneously over time
Avoiding routine postdilation of the stent may help to reduce undesired embolic events.
Judicious use of balloon dilation may be required in recalcitrant or heavily calcified stenosis, in
which the luminal diameter is inadequate after initial stent deployment
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33. POST DILATION
if possible not to post-dilate unless the post-CAS carotid diameter
is < 5 mm.
If post dilation is required, a 5-mm balloon is used to gently dilate
the stenosis. Again, atropine may be necessary
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34. EPD REMOVAL AND COMPLETION ANGIOGRAM
After the stent placement and post dilation (if needed) are completed, then the EPD must be
evaluated for trapped embolic material before it can be recaptured.
In cases where a significant embolic load is detected, an aspiration catheter should be
used to clear any trapped debris.
In the vast majority of cases, the embolic load will be minimal and the EPD can be collapsed
safely with the appropriate catheter.
Once the EPD is recaptured, removal under fluoroscopic observation is recommended
as the EPD may engage the stent margin because it is withdrawn through the stent.
Turning the patient’s head or asking the patient to cough or perform the Valsalva maneuver
may aid with removal
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35. EPD REMOVAL AND COMPLETION ANGIOGRAM
In the rare instance that typical maneuvers are not successful, increased steerability of the EPD is
required.
Replacing the recapture catheter with an angled 5F catheter will allow the EPD to be negotiated
through stent inmost cases.
After the EPD is successfully removed, a completion angiogram to include both the cervical ICA
and the intracranial circulation is performed to evaluate for residual stenosis, exclude vasospasm or
dissection, and evaluate intracranial blood flow.
This should be compared with the preprocedure angiogram, as distal emboli can be subtle.
The patient may be asked to answer simple questions or perform simple tasks as a basic neurological
evaluation prior to access discontinuation.
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36. POST-PROCEDURAL CARE
Serial neurological examinations should be performed and documented.
if post procedural hypotension is noted, volume resuscitation is typically advised .
Rarely, pharmacological pressure support and critical care monitoring are required.
If hypertension is present, it is advised to lower the blood pressure to below 150 mm
Hg systolic.
Most patients are discharged the next day with longitudinal follow-up.
Clopidogrel should be continued for 30 to 45 days, after which aspirin should be taken
for life.
Ultrasound follow-up is recommended at 3months, 6months, and then yearly.
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37. DR.NILESH TAWADE 43
Anterior-posterior and lateral projections of the cervical carotid artery show restenosis
of
the left internal carotid artery (arrow) after previous CEA.
38. DR.NILESH TAWADE 44
Lateral image of the neck shows the EPD deployed, confirmed by visibility of the four
separate radio-opaque dots (arrow).
43. CONCLUSIONS
CAS has undergone tremendous evolution over the past 20 years; however, it
continues to be the subject of much debate and scrutiny.
Large studies performed over the past decade have shown that CAS, when
performed by skilled operators, can provide a safe and durable option for
revascularization of CS.
In certain high-risk patients, some might argue that CAS is already the
standard of care.
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