2. INTRODUCTION
Stroke is the leading cause of adult disability
Third leading cause of death in North America,
Europe, South America, and Asia.
Most strokes (80% to 85%) are ischemic in
etiology.
Atherosclerotic disease (affecting the
extracranial and intracranial arterial
circulation)accounts for approx 20% of
ischemic strokes .
3. Carotid Atherosclerosis and Stroke
The carotid bifurcation has a predilection for the
development of atherosclerosis, typically at the origin
of ICA.
Plaque = dense cap of CT, SMC`s, core of lipid &
necrotic debris.
Vulnerabe plaque ; reduced amounts of collagen,
increased inflammation, thinning of the fibrous cap,
and increased cholesterol in the necrotic core.
Plaque fissuring or rupture at the carotid bifurcation
Occlusive or nonocclusive thrombus formation.
9. Natural History of Carotid Artery
Bifurcation Disease
Two dominant factors determine the risk of
ischemic complications
Symptomatic status of the lesion
Severity of stenosis
NASCET Trial = risk of any I/L stroke at 2-year F/U
in medically treated pt`s with symptomatic
stenoses of 70% to 99% was 26%.
Among pt`s with symptomatic stenoses of 50% to
69%, the 5-year risk of any I/L stroke was 22.2%.
13. Hazard of I/L ischemic stroke within 3 years after index TIA/Stroke
Cuffe et al, Stroke. 2006;37:1785-1791
14. Carotid artery disease
Definition
• Carotid artery stenosis = ≥ 50% stenosis of the
extracranial ICA
• ‘Symptomatic’ if associated with symptoms in
the preceding 6 months.
• ‘Asymptomatic’ if no prior symptoms or when
symptoms occurred >6 months ago.
17. Imaging
• DUS:- first-line carotid imaging modality to
assess extracranial ICA stenoses.
– Echolucency, intraplaque haemorrhage, surface
irregularity
– Doppler velocity (PSV,EDV) measurements
– Ratios (ICA/CCA PSV) for accurate estimation of
stenosis severity
– SRU Consensus
– Sonographic NASCET Index
18. MRI – Plaque morphology,Vulnerable plaque
CTA-Severe calcification may overestimate
stenosis severity.
MRA- does not visualize vascular calcification,
an important issue in CAS.
Transcranial Doppler- detection Spontaneous
embolisation (Uni directional high intensity
increase, short duration, random occurance,
“whistling” sound.
24. ENDOVASCULAR TECHNIQUES
CAS - less invasive alternative to CEA
Low risk of cranial nerve injury, wound
complications and/or neck haematoma
Reduce perioperative MI
25. CAS Preffered Over CEA
• Hostile neck’ (prev radiation, rec stenosis),
• C/L recurrent laryngeal nerve palsy
• Challenging surgical access [very high ICA
lesions, proximal CCA lesions]
• Pt at high risk of perioperative MI
27. EMBOLIC PROTECTION DEVICES
Controversial
Meta-analysis of 24 studies - EPD use was
associated with a lower risk of perioperative
stroke (RR 0.59; P < 0.001).
Garg N et al,J Endovasc Ther 2009;16:412–427
28. • CREST : Carotid Revascularization
Endarterectomy versus Stenting Trial.
• ACT-1 : Asymptomatic Carotid Trial
– EPDs mandatory- best result with EPDs
SPACE trial : Observed lower I/L stroke rates in
CAS pt`s without EPD (6.2%) vs. with EPD
(8.3%)
31. Open surgery vs. medical therapy
• ACAS & ACST-1 compared CEA with medical therapy in
asymptomatic pt`s with 60–99% carotid stenosis.
ACAS : 5-year rates of I/L stroke/death under CEA vs.
medical therapy were 5.1% vs. 11.0%, respectively (P =
0.0001, NNT = 18).
• 10-year risk of ‘any’ stroke rates were 13.4% vs. 17.9%,
respectively (P = 0.009, NNT = 22).
ACST-1 : 5-year rates of any stroke 6.4% vs. 11.8%,
respectively (P < 0.0001, NNT = 19).
• Fatal/ disabling stroke rates were 3.5% vs. 6.1%,
respectively (P = 0.004, NNT = 38).
32. Features associated with increased risk of stroke in patients with
asymptomatic carotid stenosis treated medically
33. Carotid revascularization: surgery vs.
stenting
Two biggest RCTs; CREST and ACT-1
ACT-1; @30day death/stroke= 2.9%. Vs 1.7%
in CAS & CEA respectively (p=0.33).
SAPPHIRE trial ; randomized symptomatic and
asymptomatic pt`s deemed ‘high risk for
surgery’ to either CEA or CAS (using EPDs
routinely
34. • The primary endpoint (30-day
death/stroke/MI and/or death or I/L stroke
between 31 days and 1 year) occurred in
12.2% of CAS pt`s and 20.1% of CEA pt`s (P =
0.053).
• At 3 years ; major I/L stroke (CAS 1.3% vs. CEA
3.3%), minor I/L stroke (6.1% vs. 3.0%) and
repeat revascularization (3.0% vs. 7.1%) were
not statistically different.
39. Symptomatic carotid artery disease
Open surgery
In a meta-analysis of all symptomatic pt`s
randomized within NASCET and ECST.
NASCET; 0–49% stenosis gained no benefit from
surgery.
CEA conferred a 7.8% ARR for stroke at 5 years in
pt`s with 50–69% stenoses (NNT = 13).
Maximum benefit was seen in pt`s with 70–99%
ICA stenoses, where the ARR for stroke was
15.6% (NNT = 6).
40. Endovascular therapy vs. open surgery
CAS - increased risk of any stroke but a
decreased risk of perioperative MI & cranial
nerve injury.
Higher rates of perioperative stroke in pt`s >70
years of age undergoing CAS.
Beyond the 30-day perioperative period, long-
term data after CAS are almost identical to
those after CEA.
44. Vertebral artery disease
• Up to 20% of ischaemic CVA involving the
posterior circulation are related to vertebral
artery disease
45. Imaging
• CTA/MRA have a higher sensitivity (94%) and
specificity (95%) than DUS (sensitivity 70%)
• MRA-Overestimate Vertebral ostial stenoses
• CTA - Underestimates the degree and
prevalence of ostial vertebral artery stenoses.
• DSA - rarely required for diagnostic purposes,
req in pt`s who are cond for revascularization.
46. Management of vertebral artery
disease
• Aspirin (or clopidogrel if aspirin is not
tolerated) and statins - irrespective of
symptoms.
• Most pt`s with asymptomatic vertebral artery
disease do not require any revascularization
• In pt`s with ischaemic events despite
antiplatelet therapy, revascularization may be
considered.
47. • VAST Trial - 162 randomized pt`s with vertebrobasilar
symptoms within the preceding 30 days and an extra-
or intracranial vertebral artery stenosis >50% to
stenting plus BMT (n = 57) or BMT alone (n = 58).
• 30 day ; Vertebrobasilar stroke or death occurred in 5%
of pt`s randomized to stenting and 2% in the medical
arm.
• At 3 years; 12% and 7% respectively
• Do not support routine endovascular interventions for
symptomatic vertebral artery stenoses unless
symptoms recur despite OMT
56. FUNDAMENTAL STEPS
1. Femoral access
2. Arch angiography
3. Selective catheterization target CCA
4. Wire placement in ECA
5. Sheath or GC placement in distal CCA
6. Placement of embolic protection device
7. Pre-dilation of lesion
8. Stent placement
9. Post-dilation of stent
10. Removal of EPD
11. Final angiography
58. Carotid Artery Stenting: The Procedure
PREPROCEDURAL ASSESSMENT
• Clinical assessment
• Advanced age -: >80 years has been associated
with significantly worse outcomes with CAS
• Decreased cerebral reserve -: presence of
dementia,cognitive impairment, and a H/O prior
strokes or lacunar infarcts increase the likelihood
that distal embolization and are relative CI for the
procedure.
59. • Anatomic assessments:
• CTA - higher spatial resolution, superior
visualization of the aortic arch compared with
MRA
• It allows an assessment of the degree of
calcification of the aortic arch and carotid
bifurcation, Not possible by MRA.
63. Intubating the guiding catheter or
sheath into the CCA
• Type I or II aortic arch-; Enter the CCA using a
slightly curved catheter — JR or Headhunter
catheter
• Bovine arch- JL, IMA, or Simmons catheters.
• Type III aortic arch with calcification, difficult
to access; if access with a general catheter is
not feasible, use Simmons or Sidewinder
catheters.
• Contact the aortic arch as little as possible
66. Baseline Angiography
• Femoral artery access
• Heparin bolus of 25 mg/kg
• Angiography of the carotid bifurcation
• Uncomplicated anatomy (i.e., type I aortic arch,
no tortuosity of the great vessels)- ; Bernstein
catheter.
• Complicated anatomies (e.g., type II or III arch,
tortuosity of the great vessels, bovine origin of
the left CCA);- Vitek or Simmons catheter.
67. Interventional Technique
• CAS steps:
1. Aspirin+ clopidogrel
2. Anticoagulation - UFH (ACT 275 - 300 Sec)
1. CI to heparin - direct thrombin inhibitor such as
bivalirudin
3. No sedation - To screen for any neurologic
change during the procedure.
68. Delivery of Sheath or Guide to the CCA
6-Fr sheath or 8-Fr guide must be placed in the distal CCA
Steps for delivery of a 6-Fr sheath in the CCA is as follows
1. CCA is engaged with a diagnostic catheter.
2. Stiff-angled Glidewire is advanced into the ECA, and the diagnostic
catheter is advanced over it.
3. Glidewire is exchanged for a superstiff Amplatz or SupraCore wire,
and then the diagnostic catheter is removed.
4. 6-Fr sheath and its dilator are delivered over the stiff wire to the
distal CCA, after which the dilator is removed.
Guidewires and catheters should never be placed across the carotid
lesion to deliver the sheath or guide to the CCA.
It is preferable to refer the pt for CEA than to persist in risky
attempts to deliver the guide or sheath.
69. Delivery of Embolic Protection Device
• Use of EPDs is currently considered the
standard of care during CAS.
• Filter-type EPD: most popular, user friendly,
allow continued antegrade flow
• Multiple filter-type EPDs have received FDA
approval, including Accunet, EmboShield,
Spider, Angioguard, FilterWire, and FiberNet
devices.
73. Filter should be deployed in a straight and nondiseased
portion of the cervical ICA
There must be at least 3 to 4 cm of distance between
the proximal margin of the filter and the distal margin
of the ICA lesion
Filter-type systems have replaced distal occlusion
balloon EPDs, which were the first type of EPD used
during a carotid intervention (c.1998).
Most recent group of EPDs developed for carotid
intervention are the proximal occlusion devices (e.g.,
the Parodi Antiembolism System from Gore Medical,
Flagstaff, AZ, and the MO.MA System from Medtronic).
76. Angioplasty and Stenting
PREDILATION
After placement of the EPD system, the lesion is
usually predilated to facilitate stent delivery.
Low-profile coronary balloons with diameters of
3.0 - 4.0 mm are used.
Attempts to deliver the stent without predilation
have been associated with a greater amount of
atheroembolism, likely related to increased
trauma to the lesion with forcible passage of the
stent across a tight stenosis.
77. Stent Selection and Placement
Flexible self-expanding stents - conform to the
tortuous anatomy, changes in vessel shape
associated with neck movements.
Nitinol, a nickel-titanium alloy, is the most
widely used material for carotid self-
expanding stents; because of its large elastic
range.
79. Nominal diameter of the stent used should be 1 to 2 mm larger
than the diameter of the largest treated vessel (usually the CCA).
Open-cell-design nitinol stents with large open-cell areas and highly
flexible interconnecting bridges (e.g., Precise stent, Cordis; Zilver
stent, Cook, Bloomington, IN)—may be optimal for treating lesions
in tortuous locations.
Calcified lesions should be treated with stents that have a high
radial force and a moderate outward expansive force, such as
nitinol stents with a closed-cell design (e.g., Xact stent, Abbott).
Lesions with the greatest risk for distal embolism should be treated
with stents that provide greater vessel scaffolding (closed-cell
nitinol or cobalt alloy stents; e.g., WALLSTENT, Xact).
80. POSTDILATION
• 4.5 - 5.5-mm diameter noncompliant balloon (e.g., Aviator,
Cordis; Sterling, Boston Scientific).
• Postdilation is associated with the greatest propensity for
plaque embolization; therefore experienced operators
advocate a conservative approach to postdilation.
• A residual stenosis of less than 20% is usually accepted.
• When filter-type EPDs are being used, “slow flow,” is an
important finding
• This phenomenon is caused by excessive distal
embolization of plaque elements that occlude the filter
pores, compromising antegrade flow through the filter .
82. Predictors of slow flow
– Treatment of symptomatic lesions
– Increased patient age
– Increased stent diameter
To prevent distal embolization of debris at the time of
filter retrieval, use of an Export catheter to aspirate 40
to 60 mL of blood from the column of blood proximal
to the filter before retrieval of the filter EPD.
If slow flow is observed after stent deployment,
poststent dilation is discouraged bcz it will probably
exacerbate the degree of embolization from the Tt site.
83. Removal of the EPDs and Final
Angiography
Remove filter - type EPD by advancing a retrieval
sheath over the interventional wire and
collapsing the filter.
The collapsed filter is then withdrawn carefully
across the stent and removed.
Rarely, the pt have to turn head or external
compression may have to be applied to carotid.
Final angiography at the Tt site, the EPD landing
zone, and the I/L anterior cerebral circulation.
84. Slow flow and rationale for aspiration
J Am Coll Cardiol. 2005;46[8]:1466–1472
85. Postprocedural Care and Follow-Up
All pt`s should receive lifelong aspirin therapy
unless contraindicated.
Clopidogrel is recommended for a minimum of 4
weeks after the procedure.
Pt`s are seen at 1 month and 12 months after the
procedure for clinical assessment and a carotid
ultrasound study to screen for in-stent stenosis.
Thereafter, yearly carotid ultrasound examination
is recommended.
88. COMPLICATIONS OF CAROTID
INTERVENTION
STROKE
Risk of periprocedural stroke is most strongly related to
the pt’s symptomatic status.
Multiple observational studies of high-risk pt`s stroke
ranged from 2.3% - 6.9%.
High-risk registry studies in recent years reporting
stroke rates of 2.3% - 4.4%.
Approx 80% of these strokes I/L to the Tt site; --> 25% -
33% classified as major strokes (i.e., persistence of
neurologic deficit beyond 30 days).
Majority of strokes occur at the time of the CAS
procedure.
90. After 30 days, the risk of I/L stroke with CAS is extremely
low.
Most procedure-related strokes (>80%) are ischemic in
nature
Mechanism ; distal embolization of plaque due to
manipulation of catheters and wires in the aortic arch/CCA
and embolization of plaque elements with angioplasty and
stent.
Hemorrhagic strokes accounted for 15% - 20% of all strokes
in larger high-risk stent registries.
Slightly later than that of ischemic strokes, and the
dominant mechanism is probably related to cerebral
hyperperfusion after CAS.
91. Hemodynamic Depression
• Baroreceptors are activated by increases in blood
pressure.
• Signals from these receptors are transmitted through
the glossopharyngeal nerve (cranial nerve IX) toward
the vasomotor center in the medulla, which in turn
activates the vagus nerve (cranial nerve X) and
reticulospinal tract, resulting in peripheral vasodilation,
bradycardia, and decreased cardiac contractility .
• Transient pressure from angioplasty and more
prolonged pressure from self-expanding stents
activates these baroreceptors, causing the hypotension
and bradycardia frequently associated with CAS.
92.
93. It is uncommon for significant effects to be seen beyond 48
to 72 hours, because the baroreceptors gradually adapt to
the pressure from the self-expanding stent.
In a retrospective analysis of 500 consecutive CAS cases
from a single center, the frequency of procedural
hemodynamic depression—defined as a systolic blood
pressure less than 90 mm Hg or bradycardia of less than 60
beats/min—was 42%, with persistent hemodynamic
depression after the procedure in 17% of cases.
Prophylactic measures include withholding
antihypertensive medications on the morning of the
procedure and ensuring adequate hydration with IV fluids
before and during the procedure.
94. Hyperperfusion Syndrome
Cerebral hyperperfusion; bcz of improved flow to a
chronically ischemic cerebral territory.
Caused by significant increases in cerebral blood flow
(>100% of baseline) after revascularization, which in
combination with impaired cerebral autoregulation
results in transudation of fluid into the brain’s
interstitium and cerebral edema .
Clinically ; pt`s typically complain of a throbbing
headache I/L to the revascularization site. Associated
symptoms include nausea, vomiting, confusion, and
visual disturbances. In the most severe cases, patients
develop focal neurologic deficits and seizures.
95. The feared complication of the hyperperfusion
syndrome is intracerebral or subarachnoid
hemorrhage, which is associated with a high
mortality rate (40% to 60%) and severe morbidity
among survivors.
In 12 observational studies published since 2003,
the incidence of hyperperfusion syndrome was
1.3% (73 of 5431 cases).
Most cases manifested within 24 hours after the
procedure, and cases beyond 2 to 4 days were
rare.
96. • Risk factors : for cerebral hyperperfusion after
CAS
– Include pre existing hypertension, postprocedural
hypertension, C/L carotid occlusion, critical I/L carotid
stenosis, and incomplete circle of Willis.
• Aggressive control of BP after CAS is
recommended in all pt`s to prevent it.
• Management of hyperperfusion syndrome are
prompt diagnosis and emergent institution of
therapy.
97. Diagnosis is clinical, based on the pt’s symptoms.
Several antihypertensive agents are
contraindicated bcz they are associated with
increased cerebral blood flow, including glycerol
trinitrate, nitroprusside, calcium channel
antagonists, and ACE inhibitors.
Recommended agents :include β-blockers,
labetalol and clonidine which have favorable
effects on cerebral blood flow.
99. Adverse Cardiac Events
30-day incidence of MI has been in the range
of 0% - 2.4%.
SAPPHIRE trial; CAS was compared with CEA
in high-risk pt`s,, significant and consistent
reduction in MI with CAS (2.4% vs 6.1%; P =
.04).
CREST; 30-day MI rates of 1.1% in the CAS arm
and 2.3% in the CEA group (P = .03)
100. Restenosis
ISR is an important late complication of CAS.
Duplex ultrasound is used for screening
carotid ISR
Incidence of severe ISR (≥80%) is 3% - 4% at
approx 18 months of F/U.
ISR at 2 years in RCT`s of CAS and CEA was
11.1% (lower cutoff value i.e., ≥70% was used
to define it).
Editor's Notes
Carotid intervention is important target for stroke prevention.
ICA- internal carotid artery,, Plaque is similar to other sites ,, CT=connective tissue, SMCs=smooth muscle cells, thin fibrous cap <65µm
CIRCLE OF WILLIS
NASCET=NORTH AMERICAN SYMPTOMATIC CAROTID ENDARTERECTOMY TRIA,, ECST= EUROPEAN CAROTID SURGERY TRIAL.
Angiographic images from the carotid bifurcation show the spectrum of atherosclerotic disease at this site. (A) Minimal disease at the origin of the internal carotid artery (ICA). (B) Mild stenosis extending from the distal common carotid artery (CCA) into the proximal ICA. (C) Moderate eccentric stenosis in the proximal portion of the ICA. (D) A thrombotic lesion in the proximal portion of the ICA in a patient with recent stroke. (E) High-grade stenosis in the proximal portion of the ICA. Notice that atherosclerotic plaque tends to accumulate in the posterior aspect of the ICA.
Angiographic appearance of “near-occlusion” of the internal carotid artery (ICA). (A) Reduction in diameter of the ICA compared with the external carotid artery (ECA) reflects a mild form of near-occlusion of ICA (arrow). (B) Major collapse of the ICA beyond critical stenosis (arrow) reflects a severe form of near-occlusion of the ICA and is often referred to as a string sign.
NASCET=(North American Symptomatic Carotid Endarterectomy Trial),, I/L-ipsilateral,, There is a close temporal relationship between these recurrent strokes and the index event, with a steep exponential decline in risk within the first months, followed by a more gradual decline and ultimate normalization of risk at 2 to 3 years (Fig. 46.3).
Change in risk of ipsilateral stroke over time in medically treated (green line) and surgically treated (purple line) patients with symptomatic stenosis of 50% to 69% (A)
70% to 99% (B) in the NASCET trial (North American Symptomatic Carotid Endarterectomy Trial). Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. CEA involves removing the atheroma and associated damaged intima (Fig. 4), thereby reducing the risk of future strokes or TIAs. The main risks of CEA surgery are stroke (2-3%), nerve damage to the hypoglossal, glossopharngeal, or vagus nerve, myocardial infarctions, local bleeding, and infection.
Risk of any stroke or operative death in medically treated (green line) and surgically treated (purple line) symptomatic patients with varying degrees of carotid artery stenosis. (A) Near-occlusion. (B) 70% to 99%. (C) 50% to 69%. (D) 30% to 49%. ARR, Absolute risk reduction; CEA, carotid endarterectomy. Analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis. Carotid artery stenting (CAS).
If the life expectancy of the patient is less than 5 years, then significant benefit should not be anticipated.
In addition, participation in these trials involving patients with asymptomatic carotid stenoses required documentation of a perioperative stroke and death rate of less than 3% at the investigation site, and the generalization of these findings is predicated on reproducing similar procedural outcomes.
Three major RCTs in symptomatic patients, CEA compared with medical therapy reduced the end point of stroke or operative death at 5 years in patients with carotid stenoses of 50% or greater, as assessed by carotid angiography using the NASCET criteria (Fig. 46.6).13 This benefit was more pronounced in patients with stenoses of 70% to 99% (absolute risk reduction [ARR] 15.3%; 95% confidence interval [CI] 9.8% to 20.7%) than in those with stenoses of 50% to 69% (ARR 7.8%; 95% CI 3.1% to 12.5%). In addition, the crossover of the event free curves occurred very early in the patient cohort with 70% to 99% stenoses (1 to 2 months) compared with the patient cohort with 50% to 69% stenosis (1 year).
The incidence of perioperative stroke and/or death in these studies was uniformly less than 6%; the benefits derived from CEA are predicated on the maintenance of similar procedural outcomes.
No significant benefit was observed in patients with near-occlusion of the carotid artery (ARR 0.1%; 95% CI −10.3 to 10.2), likely related to the lower risk of recurrent stroke with medical therapy in this group. These studies were performed in the late 1980s and early to mid-1990s; therefore the only stipulated medical therapy in the nonsurgical arm was aspirin.
Contemporary medical therapy would likely attenuate the observed benefit associated with CEA. However, given the magnitude of the observed benefit associated with CEA in symptomatic patients, investigators have been reluctant to repeat randomized studies using contemporary medical therapy alone as a treatment arm. Compared with medical therapy, CEA has also been shown to significantly reduce the incidence of stroke or operative death at 5-year follow-up in asymptomatic patients with carotid stenoses of 60% or greater, as assessed by carotid ultrasound (11.8% vs. 6.4%; ARR 5.4%; 95% CI 3% to 7.8%).6 It is important to
Hazard of ipsilateral ischemic stroke within 3 years after index transient ischemic attack or stroke as a function of the percent of carotid stenosis, determined with the use of biplane angiographic views. (Adapted from Cuffe RL, Rothwell PM. Effect of nonoptimal imaging on the relationship between the measured degree of symptomatic carotid stenosis and risk of ischemic stroke.)
CAS=CAROTID ARTERY STENOSIS,, According to the definitions in major trials (NASCET), carotid stenosis is defined as:
DM/HT/DYSLIPIDEMIA/SMOKING/OBESITY,OVERWEIGHT/SEDENTARY LIFESTYLE/PSYCHOSOCIAL/ DIET NUTRITION/ALC./ H/O TIA,STROKE,CARD DS,OC PILLS,,, AGE/SEX/RACE/ETHNICITY,F/H,,,, ABCD2 RISK SCORE FOR TIA-RISK OF STROKE REC, 6-7==8.1% WITHIN 90 DAYS
LEAD = lower extremity artery disease
>70% STENOSIS-: Peak syst vel>230 cm/s, end diast vel >100cm/s, ICA/CCA PSV > 4.,, 50-69% 125-230, ICA/CCA PSV 2-4,,
::,, NORMAL , ICA PSV <125 CM/S, ICA/CCA PSV <2, ICA EDV < 40 CM/S,, NASCET- PS spectral broadening vd PSV> 270CM/S, OR EDV> 110 CM/S,, ICA/CCA PSV > 4.,, SRU- SOCIETY OF RADILOGIST IN ULTRASOUND,,
Signals,, CAS-CARITID ARTERY STENTING,,VULERABLE PLAQUE- CIMT,EROSION,ULCERATION,THROMBUS,INTRAPLAQUE H`GE,INFLAMMATION,CALCIFICATION-LOW,FIBROUS CAP-THIN,LIPID CORE-RICH, MICROEMBOLI SIGNAL ON TRANSCRANIAL DOPPLER
DUS-DUPLEX ULTRASOUND
In a subgroup analysis from the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), the 4-year mortality was significantly higher [HR 3.40 (95% CI 1.67–6.92)] in patients suffering a perioperative MI
CREST – Stenting vs Endrectomy for treatment of carotid artery stenosis,, SPACE-Stent protected angioplasty vs carotid endarterectomy.
SPACE trial (Stent-Protected Angioplasty versus Carotid Endarterectomy)
EPD-EMBOLIC PROTECTION DEVICE, ESC-2017
ACAS (Asymptomatic Carotid Atherosclerosis Study ),, ACST-1 (Asymptomatic Carotid Surgery Trial )
HITS = high intensity transient signal; MRA = magnetic resonance angiography; TIA = transient ischaemic attack. a Age is not a predictor of poorer outcome. b More than 40 mm2 on digital analysis.
CREST (STENTING VS ENDARTERECTOMY FOR TREATMENT OF CAROTID ARTERY STENOSIS),,ACT-1 (RANDOMISED TRIAL OF STENT VS SURGEY FOR ASYMPTOMATIC CARITID STENOSIS),, The Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial. High surgical risk was defined as clinically significant cardiac disease, severe pulmonary disease, contralateral ICA occlusion, contralateral recurrent laryngeal nerve palsy, previous radical neck surgery or radiotherapy, recurrent stenosis after CEA and age >80 years.
HIGH SURGICAL RISK FOR CEA d = Age >80 years, clinically significant cardiac disease, severe pulmonary disease, contralateral internal carotid artery occlusion, contralateral recurrent laryngeal nerve palsy, previous radical neck surgery or radiotherapy and recurrent stenosis after CEA.
aDefined as need for home oxygen, partial pressure of oxygen (Po2)
European Carotid Surgery Trial (ECST), NASCET (North American Symptomatic Carotid Endartectomy Trial),, A number of clinical/imaging features are associated with an increased rate of late stroke in symptomatic patients with 50–99% stenoses if treated medically: increasing age (especially >75 years, symptoms within 14 days, male sex, hemispheric (vs. retinal) symptoms, cortical (vs. lacunar) stroke, increasing number of medical comorbidities, irregular stenoses, increasing stenosis severity, contralateral occlusion, tandem intracranial stenoses and a failure to recruit intracranial collaterals. The risk of stroke is high within the first days after TIA. The early risk of stroke in patients with 50–99% ICA stenoses ranged from 5 to 8% within 48 h after TIA, up to 17% by 72 h, 8–22% by 7 days and 11–25% at 14 day
In contrast, age had little effect on CEA outcomes. patients undergoing CEA within 7 days of symptoms had a 2.8% risk of stroke/death compared with 9.4% after CAS. Patients undergoing CEA 8–14 days after symptom onset had a 3.4% risk of stroke/death compared with 8.6% after CAS. In the CREST, CAS performed within 14 days of symptom onset incurred a 5.6% rate of death/stroke compared with 2.6% after CEA. In symptomatic patients undergoing an intervention at 15–60 days, CAS was associated with a 6.1% risk of death/stroke compared with 2.3% after CEA. The increase in perioperative stroke in elderly CAS patients may be due to a greater burden of aortic arch disease.
Management of extracranial carotid artery disease. BMT = best medical therapy; CAS = carotid artery stenting; CEA = carotid endarterectomy; CTA = computed tomography angiography; MRA = magnetic resonance angiography; TIA = transient ischaemic attack. a With post-stenotic internal carotid artery narrowed to the point of near occlusion. High risk for CEA c Age > 80 years, clinically significant cardiac disease, severe pulmonary disease, contralateral internal carotid artery occlusion, contralateral recurrent laryngeal nerve palsy, previous radical neck surgery or radiotherapy and recurrent stenosis after CEA.
In patients with known vertebral artery stenoses, it is reasonable to use DUS to assess stenosis progression and to follow patients after revascularization therapies
The Vertebral Artery Stenting Trial (VAST),, OMT- Optimal medical therapy
The type of aortic arch is based on the vertical distance between the origin of the brachiocephalic artery (dotted line) and the top of the arch (solid line). In type I, this distance is less than 1 LCCA diameter. In type II, the distance is between 1 and 2 LCCA diameters, and in type III, the distance is greater than 2 LCCA diameters. Pre-procedural aortic arch evaluation using magnetic resonance angiograms not only helps to distinguish arch type, but also reduces the use of contrast agent by eliminating an aortogram from the procedure.
LCCA = left common carotid artery.
JL=Judkins left,, Judkins right (JR),, CCA=common carotid artery,, Bovine arch is the most common variant of the aortic arch and occurs when the brachiocephalic (innominate) artery shares a common origin with the left common carotid artery.
Engagement methods with the Simmons catheter. (A) If the Simmons catheter is inserted into the opposite iliac artery and then pushed toward the abdominal aorta, an inverted U-shaped curve of the catheter can be made. (B) After entering the left subclavian artery, the Simmons catheter can be flexed, or the catheter can be forced into curved flexion by pushing it with the support of the aorta. (C) The Simmons catheter can be introduced into either the innominate or left carotid arterial ostium by rotating and manipulating and can subsequently be deeply engaged with slow withdrawal of the catheter.
common carotid artery
CI=CONTRAINDICATION,, In a cohort of 3555 patients from the Carotid Artery Revascularization and Endarterectomy (CARE) registry, bivalirudin was associated with less need for transfusion (0.9% vs. 1.5%; P = .01) and no difference in myocardial infarction (MI), stroke, and death at 30 days, compared with unfractionated heparin in a propensity score analysis.
CCA=Common Carotid Artery,, In patients with difficult aortic arch anatomy, bovine origin of the left CCA, occlusion of the external carotid artery (ECA), distal CCA lesions, or significant tortuosity of the great vessels, this can be one of the most technically challenging parts of the procedure. This portion of the procedure is “unprotected” in that there is no distal EPD to protect against distal embolization, so the safety of this step is heavily operator dependent.
during carotid intervention—imp for pt`s with compromised collateral flow to the I/L carotid territory (e.g., pt`s with C/L carotid artery disease or occlusion).
Examples of filter-type embolic protection devices used during carotid intervention. (A) Angioguard XP (Cordis, Warren, NJ). (B) Accunet (Abbott Vascular, Abbott Park, IL). (C) Spider (ev3, Plymouth, MN). (D) FilterWire EX (Boston Scientific, Natick, MA). (E) FilterWire EZ (Boston Scientific). (F) Interceptor (Medtronic, Minneapolis, MN).
Although there is some variation in the individual design of these devices, they typically contain a polyurethane membrane with pores of fixed size (ranging from 80 to 140 μm in different devices), supported by a nitinol frame.
The Spider and Interceptor EPDs are unique in that the filter pores are formed by a nitinol mesh.
Each filter is integrated with a 0.014-inch guidewire with a 3- to 4-cm shapeable floppy tip.
With the exception of the EmboShield and Spider devices, the filter is fixed to the wire.
The technique for delivery of a filter-type EPD varies according to the design of the system.
In systems such as the Accunet, FilterWire EZ, or Angioguard, the filter is delivered in a collapsed form across the carotid lesion on the attached guidewire.
With the EmboShield system, a unique 0.014-inch wire (BareWire) is used to cross the lesion first; the filter is then delivered in a collapsed form over this wire and deployed over the distal portion of the wire.
The Spider system allows the lesion to be crossed using any 0.014-inch wire followed by a 2.9-Fr delivery catheter.
It allows delivery of the Spider filter, which is integrated with a dedicated 0.014-inch wire that allows a small range of independent motion of the wire and filter.
Predilation of the carotid lesion before delivery of the filter-type EPD is required in fewer than 1% to 2% of cases.
If it is required, a small-caliber coronary balloon (i.e., 2.0-mm diameter) that minimizes the risk of distal embolization should be used.
Angiographic images from a carotid artery stent procedure. (A) Baseline angiographic image shows severe internal carotid artery stenosis (arrow). (B) Placement of filter-type embolic protection device (5.5-mm-diameter Accunet filter, Abbott Vascular, Abbott Park, IL). (C) Predilation (4.0- by 20-mm Maverick balloon, Boston Scientific, Natick, MA). (D) Placement of tapered 6- to 8-mm-diameter by 30-mm-long selfexpanding nitinol stent (Acculink, Abbott Vascular). (E) Postdilation with 5.0- by 20-mm Aviator balloon (Cordis, Warren, NJ). (F) Final angiographic appearance after removal of filter
Slow flow is manifested by delayed antegrade flow in the ICA and may vary from complete cessation of antegrade flow to mild delay of ICA flow compared with the ECA.
Slow flow is manifested by delayed antegrade flow in the ICA and may vary from complete cessation of antegrade flow to mild delay of ICA flow compared with the ECA.
The phenomenon can occur in up to 8% to 10% of cases and is most commonly observed after postdilation of the stent (75% of cases) or after stent deployment (25% of cases).
Angiographic appearance and complication of slow flow during carotid intervention. (A) Baseline angiogram shows critical bulky stenosis at the origin of the right internal carotid artery (ICA) (arrow) in a symptomatic patient. (B) Angiographic appearance after poststent dilation shows cessation of flow in the ICA (arrow). Notice the complete filling of the external carotid artery. (C) Angiographic appearance after aspiration of the column of blood proximal to the filter and subsequent retrieval of the filter. (D) Angiogram of the middle cerebral artery after retrieval of the filter shows occlusion of one of its branches (arrow).
In pt`s with slow flow, the column of blood proximal to the filter has not been appropriately cleared of debris embolized from the treatment site by the filter EPD.
Schematic diagram of proposed mechanism of slow flow and rationale for aspiration. (A) Carotid bifurcation lesion with filter placed distally. (B and C) Balloon angioplasty and stenting result in embolization of debris from atherosclerotic plaque toward the filter, causing occlusion of filter pores and accumulation of debris in the column of blood proximal to the filter. (D and E) Aspiration proximal to the filter removes debris from the column of blood without affecting the debris causing occlusion of the filter. Slow-flow phenomenon during carotid artery intervention with embolic protection devices: predictors and clinical outcome.
30-day incidence of stroke after CAS in multiple observational studies of high-risk pt`s has ranged from 2.3% - 6.9%.
The 30-day rate of stroke in the four contemporary trials of normal-risk, symptomatic patients ranged from 5% to 9% (Table 46.4). A lower 30-day stroke rate of 2.5% was also reported in an asymptomatic subgroup from one trial of normal-risk patients.
ACT, Asymptomatic Carotid Trial; CAS, carotid artery stenting; CEA, carotid endarterectomy; CREST, Carotid Revascularization Endarterectomy Versus Stenting Trial; EVA-3S, Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis; ICCS, International Carotid Stenting Study; NA, not applicable; NR, not reported; NS, not statistically significant but specific P values not reported; SPACE, Stent-Supported Percutaneous Angioplasty of the Carotid Artery Versus Endarterectomy trial.
In the Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial, there were only two additional strokes (both minor) in the period between 30 days and 1 year after CAS among 167 patients, emphasizing the long-term safety of the procedure. Neurologic deficits during the CAS procedure should be assumed to be ischemic in nature, and immediate cerebral angiography should be performed. A normal angiogram is associated with an excellent clinical outcome, and no further treatment should be instituted. In contrast, occlusion of a large artery (≥2 to 2.5 mm diameter) is associated with a poor neurologic outcome, and attempted recanalization using a combination of mechanical (i.e., angioplasty) and pharmacologic (i.e., thrombolytics, glycoprotein IIb/IIIa inhibitors) therapies by qualified interventionalists with experience in intracranial intervention are reasonable. However, even in skilled hands, the outcome of such rescue maneuvers is unpredictable because conventional therapies have largely been designed to treat thrombus and the occlusive emboli in the setting of CAS are composed of atheromatous debris.
In general, these hemodynamic effects are seen immediately at the time of intervention; in some patients, theypersist into the postprocedural period for 24 to 48 hours.
Diagrammatic representation of the effect of activation of mechanoreceptors in the carotid sinus during carotid intervention.
The location of the lesion at the carotid bulb was a predictor of the event.
Prior endarterectomy was associated with a reduced incidence of hemodynamic depression, most likely because of denervation of the carotid sinus.
Some operators routinely administer atropine (0.25 to 0.5 mg IV) before the angioplasty and stenting portion of the procedure, whereas others restrict its use to patients who have critical aortic stenosis or critical coronary artery disease or who demonstrate an exaggerated hemodynamic response to angioplasty or stent deployment. In the presence of severe asymptomatic (i.e., systolic blood pressure
Based on data in patients undergoing carotid revascularization with CEA, an increased risk of the syndrome likely persists up to 28 days after CAS.
The rate of hemorrhagic complications of the syndrome after CAS appears to be high, with 25% to 60% of cases being complicated by intraparenchymal or subarachnoid hemorrhage
blood pressure
Patients should be cared for in an intensive care setting that facilitates meticulous control of systemic arterial pressure. After institution of treatment, imaging studies (i.e., CT and MR imaging) are helpful to screen for hemorrhagic complications and assess for the presence of cerebral edema. In addition, transcranial Doppler ultrasonography documenting a significant increase in flow velocity (>150% to 300% compared with baseline) in the ipsilateral middle cerebral artery is useful in confirming the diagnosis.
Graph showing the increase in cerebral blood flow (CBF) after carotid endarterectomy. Increase in CBF >100% from baseline defines the patient group with cerebral hyperperfusion (purple circles). Within this group, two patients (arrows) developed clinical signs and symptoms consistent with cerebral hyperperfusion syndrome (CHS). Cerebral hyperperfusion syndrome.
Carotid Revascularization Endarterectomy versus Stenting Trial