Carotid endarterectomy

Carotid endarterectomy

Anesthesia type	General Regional/MAC
Airway	ETT
Lines and access	Large bore IV x2
Monitors	Standard 5-lead ECG Arterial line ± EEG ± Neuromonitoring ACT
Primary anesthetic considerations
Preoperative	Evaluate neurologic deficits Consider CAD/MI risk
Intraoperative	Heparin anticoagulation Decrease CMRO2 during cross clamp
Postoperative	Avoid hypertension (risk of hyperperfusion syndrome) Monitor for neck hematoma
Article quality
Editor rating	Comprehensive
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Carotid endarterectomy (CEA) is a surgical procedure for treating occlusive atherosclerotic disease involving the common and internal carotid arteries. The procedure is more effective than medical management for patients with high grade stenosis (70–99%), symptomatic moderate stenosis (50-69%), or asymptomatic high-grade stenosis (≥ 60%). CEA involves making a longitudinal incision along the anterior border of the sternocleidomastoid muscle to expose the common, internal, and external carotid arteries as well as the carotid sinus. The carotid artery is then opened and the atherosclerotic plaque is removed. Opening of the carotid artery requires occlusion of the proximal common carotid and distal internal and external carotid arteries, which requires adequate collateral flow from the contralateral common carotid artery or placement of an internal shunt between the proximal common carotid and the distal internal carotid arteries. On removal of the atherosclerotic plaque, the media and adventitia of the arteries may be re-approximated or a graft may be used. These grafts are typically synthetic, but vein grafts are occasionally used.

Preoperative management

Patient evaluation

System	Considerations
Neurologic	Evaluate plaque location and adequacy of collateral flow with carotid angiograms prior to surgery
Cardiovascular	Preoperative ECG is useful as perioperative MI is the most common major postoperative complication. Uncontrolled hypertension or diabetes, as well as recent MI are reasons to delay the case.
Pulmonary	ABGs, Spirometry, and CXRs are useful only if otherwise indicated from the H&P
Hematologic	Anti-platelet agents (typically aspirin) are typically initiated preoperatively and continued until the day of surgery to prevent perioperative thromboembolic complications.

Labs and studies

• No unique laboratory evaluation is necessary

Patient preparation and premedication

• Premedication in CEA may complicate the immediate postoperative evaluation for stroke or TIA.
• Use of preoperative benzodiazepines and opioids should be limited.
• If a discussion of the operation and safety steps is inadequate to alleviate the patient's fear, a small dose of midazolam is preferred to opioid premedication.

Regional and neuraxial techniques

• Superficial cervical plexus blocks + supplemental field blocks by surgeon
• Deep cervical plexus blocks are now avoided due to concomitant Horner's Syndrome, phrenic nerve block, and recurrent laryngeal nerve injuries
• Patients receiving regional anesthesia for CEA have decreased ICU times and may have decreased need for surgical shunts. Regional anesthesia for CEA, however, does not provide cerebral protection afforded by general anesthesia and it makes conversion to GETA more challenging should the need arise.

Intraoperative management

Monitoring and access

• Standard ASA monitors
• Arterial line is required as it allows prompt vasopressor titration in response to changes in blood pressure, particularly if induced-hypertension is being used during carotid clamping.
  • Invasive blood pressure monitoring is particularly useful during the immediate postoperative period to monitor for cerebral hyperperfusion syndrome.
• Will require second arterial line transducer if surgeon measures stump pressures
• Central access is not typically required.

• EEG monitoring, somatosensory evoked potentials (SSEPs), and motor evoked potentials (MEPs) may be used to assess cerebral perfusion.

Induction and airway management

• If general anesthesia is chosen, endotracheal intubation is preferred over placing an LMA.
• Induction medications are dependent on patient comorbidies, but caution should be used with ketamine as it increases CMRO2 at a time when cerebral blood flow is limited.
• For regional anesthesia, light sedation with midazolam, fentanyl, propofol, or dexmedetomidine is reasonable. Avoid heavy sedation as patient cooperation may be required for neurologic exam.

Positioning

• Patients are positioned supine with the head turned away from operative site. Beach chair may be used for comfort in awake patients

Maintenance and surgical considerations

• Volatile anesthetics supplemented with opioids for analgesia and neuromuscular blockade is adequate for CEA without electrophysiologic monitoring (EP).
• For patients receiving EP monitoring, a total IV anesthetic with propofol and remifentanil provides excellent sedation and operating conditions.
• Heparin is required prior to carotid cross-clamping
  • ACT goal is 200-250 seconds or double the baseline value
  • Typical dose is 100 units/kg
  • Recheck ACT every 30 minutes while cross clamped
• Carotid cross clamping may induce a severe vagal response with bradycardia and hypotension. Local anesthetic infiltration by the surgeon prior to cross clamping may improve this response.
• Consider induction of burst suppression immediately prior to clamping for neuroprotection
• Induced hypertension is commonly used to promote collateral perfusion during clamping
  • Typically MAP 90-110, though will vary depending on patient factors
• Unclamping can produce a reflex bradycardia and vasodilation effect
• Reverse heparin with protamine after unclamping
  • Typical dose is 5 mg/1000 units of heparin given
  • Limited evidence supports waiting 10 minutes after unclamping to reverse
  • Confirm normalization of ACT

Blood Pressure Maintenance

• MAPs should be kept at or above the patient's awake MAP. A phenylephrine drip is a good choice because it's pure α-1 activity decreases the risk of arrhythmias.
• Wide swings in blood pressure should be expected during CEA.
• Sudden bradycardia may occur with associated hemodynamic instability, so atropine or glycopyrrolate should be available.
• Hypertension is generally avoided after unclamping in order to limit wall stress on delicate arterial suture lines. Easily titratable, and short acting anti-hypertensives such as nitroglycerin, clevidipine, nicardipine, or sodium nitroprusside, should also be immediately available.

Emergence

• Many surgeons prefer to verify neurologic status prior to extubation
• Use caution to avoid coughing and bucking which can lead to neck hematoma formation, hypertension, and even hemorrhagic stroke during emergence.
• Surgeons will often hold pressure over the neck incision during emergence and extubation.
  • Common strategies to limit coughing on emergence include using an laryngotracheal topical anesthesia (LTA) during intubation, using nitrous oxide prior to emergence, or performing a "remifentanil wakeup."

Postoperative management

Pain management

• Postoperative pain is typically mild and can be treated with local infiltration by the surgeon.
• Caution is required with opioid use because it may exacerbate respiratory depression from carotid chemoreceptor injury.

Potential complications

• Neurologic deficits may surface after emboli from plaque or shunts or from hypoperfusion during the procedure
• Plaque removal during surgery may cause baroreceptor changes causing either hypotension or hypertension requiring vasoactive medications in the recovery unit
• Postoperative hypertension may cause neck hematoma or hyperperfusion syndrome.
• Neck hematoma may result from hypertension, inadequate hemostasis, or coughing. Neck hematoma formation may distort airway anatomy making reintubation challenging.

Procedure variants

	Variant 1	Variant 2
Unique considerations
Position
Surgical time
EBL
Postoperative disposition
Pain management
Potential complications