Case 16 - CEA

Question 1

what are indications for CEA?

Answer 1

• symptomatic patients with >70% luminal narrowing of carotid artery
  
  • symptoms = TIA, reversible ischemic neurologic deficit, nondisabling stroke
• asymptomatic pts with significant luminal narrow if risk of periop morbidity and mortality is low

Question 2

what are the most serious periop complicaitons associated with CEA?

Answer 2

Neurologic and Cardiac complications

Neurologic

• include cerebral infarction, TIA, congnitive dysfunction
• etiology -
  
  • emobolization of thrombus or air during surgical manipulation
  • decreased cerebral perfusion during temporary carotid artery occlusion
  • Poor collateral flow

Cardiac

• include MI, arrythmia, hypotension, HTN
• patients with carotid artery stenosis also have CAD

Question 3

Intraop during CEA, how is patient’s neurologic status monitored?

Answer 3

1) regional anesthesia (awake patient)

• intermittent eval of motor, sensation, and language
• usually done during high-risk periods
  
  • carotid artery manipulaiton, arterial occlusion, and reperfusion

2) EEG

• considered gold standard
• ischemia = decreased amplitude, decreased frequency, or burst suppression
  
  • should see unilateral changes in regions dependent on operative artery

3) SSEPs

• stimulate peripheral nerve to cortex signal
• ischemia = increase latency, decrease amplittude

4) MEPs
* stimulate motor cotex, signal at peripheral nerve
5) TCD

• middle cerebral artery blood flow velocity on ipsilateral side
• sensitive for detecting embolic material

Question 4

how can neurologic injury occur with CEA?

Answer 4

Neurologic injury

• arterial embolizatoin during surgical manipulation
  
  • due to plaques of cartoid artery
  • due to shunt placed (plaque or air)
• decreased cerebral perfusion during arterial occlusion
  
  • poor collateral circulation
  • hypotension during this period
• reperfusion injury
• unintential arterial occlusion after surgery

Question 5

what interventions may reduce risk of neurologic injury in CEA cases?

Answer 5

1) induced HTN during artery occlusion

• during temporary artery occlusion, increase BP to promote collateral flow
• increase 10-20% above baseline
• phenylephrine

2) temporary shunt placed by surgeon
* at risk for plaque or air embolus
3) normotension during reperfusion
4) rapid emergence

• facilitates neuroexam at end of surgery
• allows for more rapid intervention like reexploration, cerbral thrombolysis, or angioplasty if indicated

5) controversies: hypothermia, anesthetic agents, paCo2

Question 6

how can carotid artery angioplasty and CEA affect postop blood pressure instability?

Answer 6

Baroreceptor = carotid sinus

Carotid artery angioplasty

• alter carotid wall mechanical properties
• increase baroreceptor sensitivity
• result = hypotension and bradycardia
  
  • due to heightened barorecptor responsiveness
• tx = phenylephrine and atropine

CEA

• transection of carotid sinus
• no baroreceptor reflex
• result = HTN
• Tx = BB, CCB, peripheral vasodilators
  *