CAROTID ARTERY DISEASE

1
CAROTID ARTERY DISEASE

• Suhail Allaqaband
• Sinai Samaritan Medical Center
• Milwaukee, WI

2

• Stroke is the third leading cause of death in the
  United States, behind heart disease and cancer
• The mortality from the acute event is about 20
• There is substantial morbidity among the
  survivors
• 18 percent are unable to return to work while up
  to 4 percent require total custodial care
• The Framingham study
• N Engl J Med 1975 Nov 6293(19)954-6

3

• Stroke may result from
• Hemorrhage (subarachnoid or intracerebral)
• Ischemic infarction which is due to
• embolization (primarily from the carotid artery
  or the heart)
• thrombosis
• low flow state

4
CAROTID ATHEROSCLEROSIS

• The proximal internal carotid artery and the
  carotid bifurcation are most frequently involved
• However, the origin of the middle cerebral
  artery, the distal carotid artery, and the
  carotid siphon may also be affected
• Ulceration frequently occurs, placing the patient
  at higher risk for embolization or thrombosis

5
Risk factors for carotid artery atherosclerosis

• Diabetes mellitus
• Obesity
• Family history

• Hypertension
• Hypercholesterolemia
• Smoking

• The risk of stroke from carotid disease is
  highest in patients who have recently sustained a
  reversible neurologic event, such as a transient
  ischemic attack

6
Clinical syndromes

• The most devastating is a completed stroke in
  which there is a persistent, disabling neurologic
  deficit
• Nondisabling strokes
• Transient ischemic attacks (TIAs)
• Reversible ischemic neurologic deficits (RINDs)
• Less commonly, patients present with
  vertebrobasilar symptoms such as diplopia,
  dizziness, dysarthria, visual loss, dysphagia, or
  ataxia

7
Diagnosis

• Established during evaluation of a symptomatic
  patient
• Screening of an asymptomatic patients with
  atherosclerotic vascular disease undergoing other
  procedures such as CABG, coronary angioplasty or
  peripheral arterial revascularization

8
Carotid bruits

• An asymptomatic bruit may prompt the physician to
  obtain evaluation of carotid artery
• However, the annual incidence of stroke
  ipsilateral to a bruit that is not preceded by a
  TIA is 1 to 3
• Among patients with a carotid bruit, only 35
  have a hemodynamically significant lesion (70 to
  90 stenosis)
• Conversely, among patients with hemodynamically
  significant stenosis, only about one-half have a
  bruit detectable on physical examination

9
Evaluation of carotid artery stenosis

• Carotid duplex ultrasonography
• Transcranial Doppler
• Computed tomographic angiography
• Magnetic resonance angiography (MRA)
• Carotid angiography (the gold standard)

10
CEREBRAL ANGIOGRAPHY

• The gold standard for imaging the carotid
  arteries
• Permits evaluation of the entire carotid artery
  system
• Provides information about plaque morphology, and
  collateral circulation which may affect
  management
• Disadvantages include its invasive nature, high
  cost, and risk of morbidity and mortality
• Risk of all neurologic complications is 4
• Risk of serious neurologic complications or death
  is approximately 1.6

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CAROTID DUPLEX ULTRASOUND

• CDUS is a noninvasive, safe, and relatively
  inexpensive technique for evaluation the carotid
  arteries
• It is 91 to 94 sensitive and 85 to 99 specific
  in detecting a significant stenosis of the ICA
• Disadvantages
• Less precise in determining stenoses of less than
  50
• Only cervical portion of the ICA can be evaluated
  
• The accuracy relies heavily upon the experience
  and expertise of the ultrasonographer

12
Transcranial Doppler

• Often used in conjunction with CDUS to evaluate
  the hemodynamic significance of ICA stenosis
• TCD examines the major intracerebral arteries
  through the orbit and at the base of the brain
• Provides additional information regarding the
  intracranial hemodynamic consequences of high
  grade carotid lesions, such as the development of
  collateral flow patterns in the circle of Willis

13
MAGNETIC RESONANCE ANGIOGRAPHY

• MRA produces a reproducible 3-D image of the
  carotid bifurcation with good sensitivity for
  detecting high grade carotid stenosis
• Compared to CDUS, MRA is less operator dependent
  and does produce an image of the artery
• However, it is more expensive, time-consuming and
  less readily available than CDUS

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PREOPERATIVE EVALUATION

• A thorough vascular history and physical
  examination to look for evidence of
  atherosclerosis elsewhere
• A thorough cardiac evaluation, since patients
  undergoing CEA are most likely to die from CAD
• exercise stress testing, or
• dobutamine echocardiography, or
• dipyridamole imaging, or
• coronary catheterization
• CT or MRI of the brain to exclude other disorders
  that might be responsible for symptoms such as
  subdural hematoma or a tumor

15
CAROTID ENDARTERECTOMY

• The first carotid endarterectomy (CEA) was
  performed in 1954
• In 1971, approximately 14,000 CEAs were
  performed by 1985 this number had reached
  107,000 even though controlled trials proving the
  efficacy of CEA compared to medical therapy had
  not been performed
• Subsequently a number of multicentered
  prospective trials evaluating this operation in
  both symptomatic and asymptomatic patients were
  initiated

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RANDOMIZED TRIALS IN SYMPTOMATIC PATIENTS
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North American Symptomatic Endarterectomy Trial
(NASCET)

• Initiated in the mid-1980s to investigate the
  efficacy of CEA in symptomatic patients
• Between December 27, 1987, and October 1, 1990,
  1,212 patients were randomized, 596 to medical
  therapy, 616 to CEA at 50 clinical centers
  throughout the United States and Canada
• Patients enrolled had had a hemispheric or
  retinal TIA or a nondisabling stroke within the
  120 days before entry

18
North American Symptomatic Endarterectomy Trial

• Patients were divided into two predetermined
  strata, carotid stenosis of 30 to 69 and 70 to
  99
• There were 659 patients with stenosis of 70 to
  99
• The study was prematurely terminated by the NIH
  because of the clear evidence of benefit from
  surgery in this selected group of patients

19
The cumulative risk of any ipsilateral stroke at
two years was 26 in the 331 medical patients and
9 in the 328 surgical patients -an absolute risk
reduction 17
20
For a major or fatal ipsilateral stroke, the
corresponding estimates were 13.1 and 2.5 -an
absolute risk reduction of 10.6
21

• These benefits were limited to patients with 70
  to 99 stenosis
• Patients with 50 to 69 stenosis had somewhat
  worse outcomes compared to those receiving
  medical therapy
• It was concluded that CEA was highly beneficial
  for patients with recent TIAs or nondisabling
  strokes with ipsilateral stenosis of 70 to 90

22
The European Carotid Surgery Trial (ECST)

• Multicenter, prospective trial
• Randomized 2518 patients with a nondisabling
  ischemic stroke, TIA, or retinal infarct due to a
  stenotic lesion in the ipsilateral carotid artery
  to medical therapy with aspirin or to surgery
• The study included 374 patients with a mild
  stenosis (0 to 29) and 778 patients with severe
  stenosis (70 to 9)
• After a three year follow-up, the following
  findings were noted in an interim report

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• Patients with mild stenosis had little risk of
  ipsilateral ischemic stroke possible benefits of
  CEA were small and outweighed by the early risks
• At 30 days, the incidence of stroke or death was
  7.5 in the patients with a severe stenosis who
  underwent CEA
• At three years patients treated with CEA had
  significant reductions
• In the incidence of ipsilateral ischemic stroke
  (2.8 versus 16.8 with aspirin alone, Plt0.0001)
• In the total risk of surgical death, surgical
  stroke, ipsilateral ischemic stroke, or any other
  stroke (12.3 versus 21.)

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The risk of disabling or fatal stroke was reduced
in patients treated with CEA
25
Randomized trial of endarterectomy for recently
symptomatic carotid stenosis final results of
the MRC European Carotid Surgery Trial (ECST)
Lancet 1998 May 9351(9113)1379-87

• The final results of this trial, based upon an
  ultimate total of 3024 patients followed for a
  mean of six years, have been reported

26
Final results of the European Carotid Surgery
Trial
27
Veterans Administration Cooperative trial

• Designed to evaluate the benefit of CEA in the
  symptomatic patients
• Stopped after one year because of results from
  the NASCET trial
• 193 men with a TIA, transient monocular
  blindness, or recent small completed strokes and
  a 50 or greater ipsilateral stenosis were
  randomized to surgery or medical therapy
• The incidence of stroke or crescendo TIA was
  significantly lower in the patients treated with
  CEA (7.7 versus 19.4 percent, Plt0.011)

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CLINICAL TRIALS IN ASYMPTOMATIC PATIENTS
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Carotid Artery Stenosis with Asymptomatic
Narrowing Operation Versus Aspirin (CASANOVA)
trial

• Randomized 410 asymptomatic patients with 50 to
  90 percent stenosis to surgery versus medical
  management alone
• The end-points were ischemic neurologic deficit
  exceeding 24 hours or death due to surgery or
  stroke
• After a mean follow-up of three years, there was
  no statistical difference between the surgical
  and medical approaches

30
Mayo Asymptomatic Carotid Endarterectomy study

• After 30 months of recruitment, at which point 71
  patients had been randomized, the study was
  terminated due to a statistically significant
  higher incidence of myocardial infarctions and
  TIAs in those undergoing surgery

31
Veterans Administration Cooperative trial

• This multicenter trial randomized 444 men with gt
  or 50 asymptomatic carotid stenosis, to aspirin
  alone or aspirin plus CEA
• The endpoint of the trial was the combined
  incidence of TIA, transient monocular blindness,
  and stroke
• After an average follow-up of almost 48 months,
  the following significant benefits were noted in
  the surgery plus aspirin group
• A lower incidence of total endpoints (8 versus
  20.6 )
• A lower incidence of ipsilateral stroke (4.7 vs
  9.4)

32
Veterans Administration Cooperative trial
33
Asymptomatic Carotid Atherosclerosis Study (ACAS)

• This trial randomized 1662 patients with gt 60
  stenosis to CEA and aspirin vs aspirin alone
• After a median follow up of 2.7 years, the
  incidence of ipsilateral stroke and any
  perioperative stroke or death rate was lower in
  the surgical group (5 versus 11 percent with
  aspirin alone, P 0.004)
• Subgroup analysis suggested that CEA was less
  effective in women, perhaps due to a higher
  incidence of perioperative complications (3.6
  versus 1.7 in men)

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COMPLICATIONS

• The perioperative mortality ranges from lt0.5 to
  3
• Majority of deaths are due to cardiac events,
  placing emphasis on the appropriate pre-op
  cardiac workup
• Stroke is the second most common cause for
  mortality
• Stroke rates range from lt 0.25 to 3

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• Nerve injury
• Vagus nerve, recurrent laryngeal nerve, facial
  nerve, hypoglossal nerve
• The glossopharyngeal nerve (A branch of this
  nerve, the nerve of Hering, innervates the
  carotid sinus and is responsible for the
  bradycardic and hypotensive)
• Bleeding resulting in neck hematoma
• Infection
• Parotitis
• Labile blood pressure
• Restenosis occurs in up to 20 of patients

36
Concomitant coronary artery bypass grafting

• Patients with significant CAD are at high risk
  for a cardiac event during CEA
• It in not clear if CABG should be staged (ie,
  performed prior to CEA) or should be combined
  with the endarterectomy

37
RECOMMENDATIONS

• Based upon these studies, the American Heart
  Association recommends the following approach in
  patients with carotid atherosclerosis
• Guidelines for carotid endarterectomy A
  statement for healthcare professions from a
  special writing group of the Stroke Council,
  American Heart Association.
• Circulation 1998 97501

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• An ipsilateral symptomatic carotid stenosis of 70
  to 99 is a proven indication for CEA, provided
  the surgical risk does not exceed 6
• CEA is acceptable, but not proven to be of
  benefit, for symptomatic patients with 30 to 69
  stenosis
• CEA is not beneficial for symptomatic patients
  with 0 to 29 stenosis
• Asymptomatic patients with stenoses of 60 to 99
  are considered to have a proven indication for
  CEA provided that their surgical risk is less
  than 3 and their life expectancy is at least
  five years

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Exclusion criteria

• An important component for CEA is the exclusion
  of patients with findings indicating that they
  are likely to do poorly. These include
• Complete occlusion of the carotid artery
• Severe comorbidity due to other surgical or
  medical illness
• A previous stroke associated with dense,
  persistent neurologic deficits
• Symptomatic patients with a hemorrhagic component
  to their stroke are at risk for exacerbation
  after reperfusion

40
Nonsurgical carotid revascularization
41
PERCUTANEOUS TRANSLUMINAL CAROTID ANGIOPLASTY

• Unlike CEA which is limited to the cervical
  carotid artery, carotid angioplasty can be
  performed in patients with more cephalad or even
  intracranial lesions
• Less invasive, can be performed with local
  anesthesia
• Lesser likelihood of morbidity from coexisting
  CAD
• Another group that may benefit from a
  percutaneous procedure is those with a "hostile"
  neck (patients who have undergone radiation
  therapy, previous neck exploration, or
  tracheostomy) who are at higher risk for
  complications following standard CEA

42
PERCUTANEOUS TRANSLUMINAL CAROTID ANGIOPLASTY

• Despite their advantages, percutaneous procedures
  are not without risk
• Catheter manipulation is associated with
  morbidity and mortality
• Acute occlusion of the carotid artery may not be
  amenable to emergency surgical correction, in
  contrast to angioplasty of other arteries
• Restenosis after carotid artery stenting may be
  difficult or impossible to treat surgically

43
Results of balloon angioplasty in the carotid
arteries. J Endovasc Surg 1996 Feb3(1)22-30

• PTA was performed in 74 patients with carotid
  stenoses proximal common (n 5), distal common
  (n 1), internal (n 65), and external (n 3)
  carotid arteries
• Angioplasty was successful in 69 of the 74
  patients
• There were only 1 major (hemiparesis) and 2 minor
  complications
• During the average 70-month observation period,
  restenosis has not occurred in any treated
  carotid artery

44
CAROTID STENTS

• Placement of a carotid stent can minimize the
  risk of two complications of percutaneous
  transluminal carotid angioplasty
• threatened vessel closure due to a dissection
• restenosis

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Stenting in the carotid artery initial
experience in 110 patientsJ Endovasc Surg 1996
Feb3(1)42-62

• In 110 patients intended for treatment, 109 were
  successfully treated
• One percutaneous procedure failed for technical
  reasons (stent could not be deployed) and was
  converted to CEA
• There were 7 strokes (2 major, 5 reversible)
  (6.4) and 5 minor transient events (4.5)
• 1 stroke patient expired (0.9), and another
  patient died of an unrelated cardiac event in
  hospital
• Clinical success at 30 days was 89.1 (98/110)
• Over a mean 7.6-month follow-up, no new
  neurological symptoms developed.

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Elective stenting of the extracranial carotid
arteries Circulation 1997 Jan 2195(2)376-81

• Percutaneous carotid angioplasty and stenting was
  evaluated prospectively in a series of 107
  patients
• This series represented a high-risk subset that
  included patients with previous ipsilateral
  endarterectomy and severe medical comorbidity
• The mean stenosis was reduced from 78 to 2
• There were 7 minor strokes, 2 major strokes, and
  1 death during the initial hospitalization
• Incidence of the combined end point of all
  strokes and death was 7.9
• Incidence of ipsilateral major stroke and death
  was 1.6
• There were no strokes during the follow-up period

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Carotid Artery Stenting in OctogenariansT.K.Bajwa
, Y. Shalev, et al.JACC 1998 Feb 819-377A

• 25 symptomatic elderly patients ( mean age 83yrs)
• 80 had significant CAD, 68 had other severe
  co-morbid conditions
• 100 success rate in reducing stenosis by carotid
  artery stenting ( from 80 stenosis to 8)
• All patients were discharged within 8 hours
• On follow-up (15 months) no new neurological
  events were found
• 1 death due to non-cerebrovascular cause
• No restenosis or stent deformity at 6 and 12
  months by carotid duplex scan

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Successful Bilateral Carotid Artery Stenting
After Failed CEA. T.K.Bajwa, Y. Shalev, et al.
JACC 1998 Feb 808-463A

• 11 patients who presented with symptomatic
  bilateral carotid artery stenosis after failed
  CEA
• All 11 had significant CAD
• Bilateral stenting was successful in all 11
  patients with reduction of stenosis from 90 to
  5
• No deaths, MI, strokes or neurological
  complications occurred
• Follow-up at 8 months showed no new neurological
  events, deaths or restenosis or stent deformity
  by carotid duplex scan

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RECOMMENDATIONS

• Although there are a number of other series
  reporting similar data to that described above,
  there are as yet no controlled studies that have
  adequately defined the role of carotid
  angioplasty and stent placement in the treatment
  of carotid disease

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On Going Clinical Trails

• CAVATAS (Carotid and Vertebral Artery
  Transluminal Angioplasty Study)
• CREST (Carotid Revascularization Endarterectomy
  versus Stent Trial)
• CASET (Carotid Artery Stent versus Endarterectomy
  Trial)