• Carotid endarterectomy (CEA) is an open surgical procedure to remove stenotic material from inside the carotid artery and improve perfusion to the brain.
• An oblique incision is made along the anterior border of the sternocleidomastoid muscle and the platysma is divided on top of the carotid bifurcation; the omohyoid muscle will often also be divided. The carotid fascia is then incised and the common carotid artery (CCA) is exposed.
• A soft, noncrushing clamp is applied to the internal carotid artery (ICA), and the external and CCA are subsequently clamped to provide a "bloodless" operating field. A shunt may be inserted above and below the clamps to maintain perfusion to the brain.
• An arteriotomy is made in the CCA, extended past the occlusion in the ICA, and the plaque is removed.
• Arterial closure is via a primary closure or patch, and the patient's neurological status should be assessed before leaving the OR.
• Embolic phenomena from the atheroma can be dislodged during clamping or plaque removal and travel up to the brain, causing infarction or TIAs.
• The decision to proceed with a CEA versus medical management is based on the degree of stenosis, presence or absence of symptoms, and concomitant risk factors (1).
  • 70–99% stenosis/symptomatic: Proceed with CEA, shown to reduce 2-year stroke risk from 26% to 9%
  • 50–69% stenosis/symptomatic: Consider CEA, especially if male, >5-year life expectancy and surgical risk of stroke/death is <6%
  • <50% stenosis/symptomatic: Medical management
  • 60–99% stenosis/asymptomatic: Consider CEA, especially if age <75, life expectancy >5 years, and surgical stroke/death risk <3%
  • <50% stenosis/asymptomatic: Medical management
• Endovascular carotid angioplasty and stenting are also available. It involves threading a catheter via a femoral arteriotomy, expanding a balloon (angioplasty), and inserting a stent to keep the artery patent. It carries an increased morbidity and mortality compared to CEA and higher rates of restenosis.

• Supine
• Head extended and turned to the contralateral side
• Shoulder roll facilitates exposure

Two inch incision over the left or right carotid

2–4 hours

50–250 mL

2–3 days

• Fluoroscopy, IV contrast dye
• Vascular shunt

Incidence

• Stroke is the 3^rd leading cause of death in the US. 700,000 strokes occur each year (of which 200,000 are recurrent).
• 180,000 CEAs are performed in the US annually and an additional 30,000 carotid stents.

Prevalence

Increases with age, male gender, hypertension, tobacco use, diabetes mellitus, hyperlipidemia, and homocysteinemia

• Stroke (embolic or ischemic) in 5–7% of CEAs
• Intracerebral hemorrhage in 0.6% of cases (60% are fatal)
• Increased risk of perioperative myocardial infarction

30-day postoperative mortality: 0.4%

History

• Baseline neurological assessment; symptomatic patients will often have a history of stroke or TIAs.
• Assessment for cerebral, coronary, renal, and/or peripheral vascular disease.
• Assess stenosis in contralateral carotid artery, as this may impact collateral flow during surgery.

Signs/Physical Exam

Carotid bruit

Labs/Studies

• Creatinine
• PT/PTT, INR
• Hemoglobin
• Electrolytes if on diuretics, ACE inhibitors, renal insufficiency
• Carotid Doppler ultrasound
• Carotid angiography
• Magnetic resonance angiography (MRA)
• Computed tomography angiography (CTA)

• Perioperative beta-blockers may be considered; they have been shown to reduce cardiac morbidity and mortality in open repair; however, may increase the risk of stroke. Titrate to heart rate.
• Perioperative statins may reduce hospital length of stay, postoperative complications, overall cost, and renal complications.

• Blood consent
• If using regional anesthesia and sedation, discuss realistic sedation goals.

• Regional: Superficial and/or deep cervical block
  • Pros: Allows for awake neurological exam and avoids hemodynamic shifts. Shunts are less commonly utilized.
  • Cons: Patient interference, neuroprotective qualities of anesthetic agents are lacking, and if the airway needs to be secured in the event of stroke, hemorrhage, seizure, agitation, or hypoxia, it must be done under less than optimal conditions.
• General anesthesia (GA) with ETT
  • Pros: Secure airway, controlled surgical field, anesthetic meds may be neuroprotective. Reduced total procedural cost.
  • Cons: Hemodynamic changes, inability to perform an intraoperative neurological exam.
• The General Anaesthesia Versus Local Anaesthesia for carotid surgery (GALA) trial showed no significant difference in stroke or death between GA and regional (2).

• Arterial line; consider awake placement if hemodynamic instability can be detrimental.
• Awake neurological exam (if possible)
• Indirect neurological monitoring
  • Flow/pressure
    • Stump pressure: Needle tip transducer inserted cephalad to the clamp, measuring back pressure in the ICA from collateral flow. Pressure goals vary by surgeon. Not very sensitive or specific for clinically significant ischemia.
    • Transcranial Doppler (TCD) at the zygomatic arch to assess MCA blood flow via the Circle of Willis. Also has the ability to detect microemboli, but these are often not clinically significant. TCD is very operator dependent and its position may interfere with the surgical field.
  • Functional
    • EEG: Raw and processed EEG has been used. Well-established EEG changes occur due to cerebral ischemia, but there are many limitations, including changes due to anesthesia, the inability to detect ischemia in deeper structures, and the need for specially trained personnel to interpret EEG.
    • SSEP (somatosensory-evoked potential): Monitors transmission of signals from peripheral nerves to the sensory cortex (can identify ischemia in deeper structures). Amplitude is decreased by many anesthetic medications and requires trained personnel to operate.
    • MEP (motor-evoked potential): Monitors transmission of signals from the motor cortex to peripheral nerves. More sensitive than SSEP to effects of anesthesia, muscle relaxation cannot be used, and specially trained personnel are required.
  • Consumption
    • JVO₂: Catheter placed in the jugular bulb to measure SpO₂. Dependent on arterial oxygen saturation, cerebral blood flow (CBF) and CRMO₂. Unclear yet if this is sensitive or specific for ischemia, and no clear threshold level has been established.

• If EEG neuromonitoring is chosen, a baseline reading is performed prior to induction.
• Slow, controlled induction is performed to avoid and treat significant hypotension that may exacerbate ischemia while achieving an adequate depth of anesthesia.

• Surgical traction on the carotid sinus can result in vagal stimulation, leading to hypotension and bradycardia. Releasing traction, or administration of glycopyrrolate/atropine may be required. Local anesthetic infiltration may abolish the response; however may last into the postoperative period.
• Heparinization should be performed prior to cross-clamping of the carotid artery.
• Placement of the cross-clamp often leads to hypertension via baroreceptor activity and increased sympathetic tone that may require treatment. It is important not to overtreat and cause hypotension, increasing the risk of ischemia.
• Shunt placement to allow distal blood flow is based on surgeon preference. Some place a shunt routinely while others do so only if there is an indication (change in neuromonitoring indicating ischemia).
• Elevation of the BP during cross-clamp time is often performed to maintain brain perfusion through collaterals and the contralateral carotid artery via the Circle of Willis.
• Unclamping may be accompanied by reflex vasodilation and bradycardia.

• Avoid coughing and bucking and hypertension that could disrupt repair.
• Neurologic exam should be performed post-op (an awake and oriented patient is beneficial).