This document discusses anesthesia considerations for carotid endarterectomy (CEA) surgery. It outlines the indications and risks of CEA, including a higher risk of stroke and death for symptomatic patients with severe carotid stenosis. Both general anesthesia and regional anesthesia can be used, though direct monitoring of cerebral function during carotid clamping favors regional. Proper patient selection, medical optimization, hemodynamic management during clamping/unclamping, and postoperative monitoring are important to reduce risks of CEA.

1. Anesthesia for
Carotid Surgery
T. Kyle Harrison MD
Department of Anesthesia
Stanford School of Medicine
Palo Alto VA Medical Center

2. Introduction
• Cerebral vascular accidents are the
third leading cause of death in the
United States.
• The majority of these CVAs are
embolic in nature.
• Carotid endarterectomies (CEA) are
commonly performed in the U.S. and
in certain populations dramatically
reduce the incidence of stroke.

3. Introduction
•Although life saving CEA
are not with out risk.
• Proper patient selection as
well as good surgical and
anesthetic care becomes vital
to assure a good outcome.

4. •Who should have an
Carotid Endarterectomy?

5. Indications for CEA
• From using data from the
large North American
Symptomatic Carotid
Endarterectomy Trail
(NASCET)-
generalizations about the
appropriate use of CEA for
carotid stenosis can be made.

6. Indications for CEA
• CEA is highly appropriate for
patients with symptomatic,
severe (70-99%) stenosis with
a maximal allowable rate of
death/stroke being 6%.

7. Indications for CEA
•Asymptomatic patients-
even with severe stenosis-
benefit less from CEA and
thus the surgery should be
performed at centers with
lower stroke/death rates
of under 3%.

8. Indications for CEA
• There is not need to wait
after a minor or nondisabling
embolic CVA as was once
thought.
• Large cortical and subcortical
CVAs with progressing deficits
should not undergo early
CEA.

9. Indications for CEA
Appropriate Patients
Symptomatic with 70-99% stenosis
Uncertain Patients
Symptomatic with 50-69% stenosis
Asymptomatic with 60-99% stenosis
Inappropriate Patients
<50% symptomatic stenosis
<60% asymptomatic stenosis
Unstable medical/Neuro status
Recent large CVA
Decreased LOC
Surgically inaccessible stenosis

10. Risk of CEA
• Ischemic stroke
• Intracerebral hemorrhage
• Myocardial ischemia and infarction
• Congestive heart failure
• Arrhythmias
• Neck hematoma with airway
obstruction
• Cranial nerve injuries

11. Risk of CEA
• The NASCET trial (1415
patients) showed an overall
rate for all strokes and death
at 90 days to be 6.5%.
However the rate for
disabling strokes and death
was 2 %.

12. Risk of CEA
• Most strokes were
thromboembolic with 1/3rd
occurring during surgery and
2/3rd post operatively.
• Cranial nerve injuries
occurred at 8.6% and neck
hematomas at 7%.

13. Risk of CEA
•Low case volumes per
surgeon (especially less
than five per year) have
consistently been
associated with poor
results.

14. Contraindications of CEA despite
symptomatic stenosis
• Recent large CVA
• Hemorrhagic CVA
• Progressing CVA
• Alterations in consciousness
• Unstable angina
• Recent MI
• Uncontrolled congestive heart failure
• Unstable hypertension or diabetes

15. Pre operative assessment
• Patients undergoing CEA should have
a complete pre operative assessment
prior to coming to the OR.
• Cardiac history should be known and
appropriate testing performed to
rule out significant CAD if warranted.
• Hypertension should be controlled
• Diabetes should be in good control
• A neurological exam should be noted

16. Pre operative assessment
• Patients should continue their
hypertensive meds on the day of
surgery.
• Patients should receive a 81 mg of
aspirin on the day of surgery.
• The patient may need to continue
Plavix if the stenosis is severe and
this should be decided in
consultation with the surgeon.

17. Surgical technique
• Exposure of
internal carotid
• Cross clamping of
internal carotid
• Complete plaque
removal
• Arteriotomy
closure
• Unclamping of
carotid artery
• Closure

18. Physiology of Carotid Clamping
• Baroreceptors are located
throughout the adventitia and media
of the carotid artery.
• Cross clamping and opening of the
artery sends low pressure input
through the glossopharyngeal nerve
to the nucleus tractus solitarius
stimulating a central systemic
pressure response.

19. Physiology of Carotid Clamping
• Carotid chemoreceptors are
also stimulated resulting in
further sympathetic
activation.

20. • Anesthetic
Management

21. Anesthetic management
• Anesthesia for CEA can be
accomplished with either a GA or
regional anesthesia.
• Regional anesthesia can be
accomplished with a deep cervical
plexus block, a superficial cervical
plexus block, and/or local
supplementation from the surgeon.

22. Anesthetic management
• Advantages of regional
anesthesia include having the
ability to directly monitor
cerebral function during cross
clamping of the carotid. In
addition there are less
hemodynamic swings with
regional anesthesia.

23. Anesthetic management
• The disadvantages to regional
anesthesia include: lack of a
secure airway, patient
discomfort/anxiety, more
difficult for the surgeon and
more difficult to convert to
GA if problems arise.

24. Anesthetic management
• The advantages of GA include a
secure airway, more ideal
operative conditions, and often
surgeon preference.
• The main disadvantage of GA is
lack of direct monitoring of
cerebral function during cross
clamp.

25. Regional vs. General
• Despite multiple studies attempting
to determine which is safer RA vs.
GA there is insufficient evidence to
prove that one is safer than the
other.
• In 2000 Bartolucci et al reviewed 17
studies involving 14,776 CEA and
found no difference between RA vs.
GA in the incidence of stroke or
neurological mortality.

26. Regional vs. General
• Many smaller studies have shown
that regional is associated with fewer
CVAs, less need to shunt and less
myocardial ischemia.
• However these findings were not
consistent with larger meta analysis
findings showing no difference.
• At this time the anesthetic plan GA
vs. RA should be decided on by the
anesthesiologist, the patient, and the
surgeon.

27. Anesthetic management
• Two peripheral IVs are
usually placed-one for
intravenous
medications/infusions and the
other as a volume line.
• An awake radial arterial line
is indicated.

28. Anesthetic management
• Vasoactive medications can be
administered through a good
functional peripheral IV thus a
central line is usually not indicated.
• If adequate PIVs can not be found
then a central line should be placed
either in the subclavian vein or
femoral vein avoiding the internal
jugular.

29. Anesthetic management
• The patient should receive minimal
sedation prior to surgery.
• Induction should be smooth avoiding
hypotension and tachycardia.
• The patient’s MAP should be
maintained at or slightly above the
patients baseline.

30. Anesthetic management
• Phenylephrine and Nipride infusions
should be in line with Nitroglycerin
and Esmolol readily available.
• Balanced anesthesia with small doses
of narcotic +/- remifentanil infusion
should be used.
• Some form of neuromuscular
blockade should be used.

31. Anesthetic management
• Either TIVA or volatile anesthetic can
be used.
• The use of N2O is controversial with
the advantage of rapid awakening vs.
the risk of worsening any air that
might be introduced into the
cerebral circulation and decreasing
the Pa02 thus reducing oxygen to
ischemic areas of the brain.

32. Anesthetic management
• In addition there is one study that
showed nitrous oxide was associated
with an increase risk of post op
myocardial ischemia.
• Hemodynamic instability should be
expected through out the case
especially with dissection and
manipulation of the carotid.

33. Anesthetic management
• Tachycardia should be
blocked with short acting
Beta blockers and one should
be aware that bradycardia
can be seen with
manipulation of the carotid
sinus.

34. Anesthetic management
• The blood pressure should be
maintained at or above baseline
through out cross clamp but reduced
after the cross clamp is removed.
• If significant bradycardia or
arrhytmias develop intraop, the
surgeon can use lidocaine at the
carotid sinus to block the vagal
nerve.

35. Anesthetic management
• The blood pressure should be at
baseline or 10-20% below baseline
after removal of the cross clamp to
prevent cerebral reperfusion injury.
• If vasodilators are being used to
control the blood pressure post
clamp, one should prepare for
increasing doses once the volatile is
decreased.

36. Anesthetic management
• Heparin is usually administered prior
to cross clamp and depending on the
time and ACT may be reversed with
protamine at the end.
• Routine antibiotics are not needed
unless a synthetic patch is used.
• Once meticulous hemostasis is
obtained by the surgeon, the patient
should be awoken quickly but with
minimal coughing and bucking.

37. Anesthetic management
• The use of LTA 4% lidocaine down
the ET prior to wake up can
significantly reduce coughing.
• The patient should be wake enough
to follow commands in the operating
room to rule out CNS injury.
• If the patient has a new deficit then
re-exploration and/or emergent
angio is indicated.

38. Post operative Care
• Following prompt awakening in the
OR the patient is usually monitored
for the first 24 hours in an intensive
care setting.
• Bradycardia and hypotension are
common in the first 12 hours
following CEA and usually respond to
fluid and atropine.
• The patient should be monitored for
signs of a neck hematoma with
prompt return to the OR if a
hematoma develops.

39. Post operative Care
• Bradycardia and hypotension are
common in the first 12 hours
following CEA and usually respond to
fluid and atropine.
• The patient should be monitored for
any signs of a neck hematoma with
prompt return to the OR if a
hematoma develops.

40. CNS Monitoring
• Many different
techniques have
been attempted to
monitor cerebral
function during
CEA.
• Stump pressure,
EEG, SSEP,
transcrainial
Doppler, and
cerebral oximetry
have all been
described.

41. CNS Monitoring
• Measurement of the distal stump
pressure has been used to assess the
degree of collateral flow with a
stump pressure of less than 50 mmHg
indicating the need for a shunt.
• EEG has also been used frequently to
monitor cerebral perfusion. Slowing
and flattening of the EEG can
indicate hypoperfusion.

42. CNS Monitoring
• EEG only reflects cortical
function where as SSEP
reflects both cortical and
subcortical function.
• SSEP is very useful but
requires special techs and a
neurologist to monitor the
waveforms.

43. CNS Monitoring
• Changes in middle cerebral artery
flow velocity as measured by trans
cranial Doppler has been used as a
marker for ischemia.
• Finally the surgeon may elect to just
place a shunt prior to any CNS
changes.

44. CNS Monitoring
• The routine use of
a shunt is however
not with out risk.
• It requires more
time to place and
it may cause
embolization of
clot, plaque or air
into the cerebral
circulation.

45. CNS Monitoring
• If you detect signs of ischemia you
should inform the surgeon and
attempt to raise the MAP. In
addition one should place the patient
on 100% 02 and check the Hct (>30).
• If on going signs of ischemia persist
despite the use of a shunt then
consider cooling the patient and
inducing burst suppression with STP.

46. Stenting for Cartoid Stenosis
• In experienced hands, carotid
angioplasty and stenting (CAS) can be
a safe alternative to CEA.
• In a recent world wide survey of CAS
reported a major stroke rate of 1.2%
and minor stroke rate of 4.8% with
an overall stroke and death rate of
4.8%.
• The restenosis rate at 36 months was
2.4%.

47. Stenting for Cartoid Stenosis
• CAS may prove to be a
valuable alternative to CEA,
especially in medically
compromised patients, but at
the present time there is lack
of evidence supporting the
widespread adoption of CAS
over CEA.

48. •Regional
Anesthesia
for
Carotid
Surgery

49. Regional Anesthesia
• Sucessful regional anesthesia
for CEA can be accomplished
with a deep cervical plexus
block, a superficial cervical
plexus block, or local
anesthesia.

50. Deep Cervical Plexus Block
• Transverse Process
of C6 (Chassaignac)
is identified.
• Horizontal line
from cricoid
cartilage should
align with C6.
• A line connecting
the mastoid
process and the C6
TP should be
drawn.

51. Deep Cervical Plexus Block
• Horizontal line from lower border of
mandible intersects transverse
process (TP) of C4.
• The TP of C3 and C2 are equidistant
between the mastoid process and the
TP of C4.
• The TPs of C2-C4 are located usually
0.5-1 cm posterior to the line joining
mastoid with Chassaignac’s tubercle.

52. Deep Cervical Plexus Block
• First needle is placed
at C4 by palpating the
TP and inserting a
1.5-2 inch 22G blunt
needle til a distinct
bony landmark is felt.
• Needle direction is
caudad, medial, and
slight posterior
direction.
• Usually 1-1.25 inches
in normal sized adult.

53. Deep Cervical Plexus Block
• Once the C4 needle is
placed repeat in
similar fashion for C2
and C3 transverse
processes.
• Once the three
needles are placed
connect a syringe
containing local to the
C2 needle and
withdraw 1-2 mm and
then check for blood
or CSF.
• After negative
aspiration test inject
5-8 cc of local and
repeat for the C3 and
C4 levels.

54. Deep Cervical Plexus Block
• Complications include:
• Vertebral artery injection with
immediate loss of consciousness,
seizure, and temporary blindness.
• Epidural or intrathecal injection with
a high spinal block.
• Phrenic nerve paralysis, recurrent
nerve paralysis, Horner’s syndrome.

55. Superficial Cervical Plexus Block
The superficial cervical
plexus is located at
the C4 level where
the external jugular
vein and crosses the
posterior border of
the SCM muscle belly.
A 25G spinal needle is
inserted
perpendicular to the
skin and advanced to
a depth equal to the
thickness of the SCM
muscle belly.

56. Superficial Cervical Plexus Block
• Once positioned 5cc
of local should be
injected.
• The needle is then
angulated and 5cc of
local injected
subcutaneous along
the lateral border of
the clavicular head of
the SCM.
• Final injection at SCM
belly cephalad to
division of sternal and
clavicular heads.

57. Regional Anesthesia
• The patient
should
remain
awake with
only minimal
sedation.

58. The End- Questions?

59. References
Carotid Endarterectomy: A Review
J. Max Findlay et al; Can.J.Neurol.Sci.
2004;31:22-36
Intraoperative Management: Carotid
Endarterectomies. Konstantin Yastrebov
Anesthesiology Clin N Am 22 (2004) 265-287.
Cervical Plexus Block for Carotid Endarterectomy.
Patrick Sullivan and Mathew Posner. Association
of Ottawa Anesthesiologists. www.anesthesia.org