Holding Pressure: Carotid Endarterectomy

Authors:

 

Sebouh Bazikian - MS4 at Keck School of Medicine of University of Southern California

 

Gowri Gowda - PGY1 at the University of California Davis Integrated Vascular Surgery Program

 

Steven Maximus- Vascular surgery attending at the University of California Davis, Director of the Aortic Center

 

 

Resources:

• Rutherford’s 10th Edition Chapters: 88, 89, and 91

• The North American Symptomatic Carotid Endarterectomy 

• Asymptomatic Carotid Atherosclerosis Study

• Audible Bleeding’s eBook chapter on cerebrovascular disease

• Houston Methodist CEA Dissection Video:

Part 1: https://www.youtube.com/watch?v=wZ8PzhwmSXQ

Part 2: https://www.youtube.com/watch?v=E_wWpRKBy4w

 

Outline:

1. Etiology of Carotid Artery Stenosis
   • Risk factors: advanced age, tobacco use, hypertension, diabetes
   • Atherosclerosis as the primary cause.

2. Development of Atherosclerotic Disease and Plaque Formation

   • LDL accumulation in arterial walls initiating plaque formation.

   • Inflammatory response, macrophage transformation, smooth muscle cell proliferation.

   • Role of turbulent blood flow at carotid bifurcation in plaque development.

3. Clinical Features of Carotid Artery Stenosis

   • Asymptomatic nature in many patients.

   • Symptomatic presentation: Transient ischemic attacks, amaurosis fugax, contralateral weakness/sensory deficit.

   • Carotid bruit as a physical finding, limitations in diagnosis.

4. Importance of Evaluating CAS

   • Assessing stenosis severity and stroke risk.

   • Revascularization benefits dependent on stenosis severity.

5. Classification of Stenosis Levels

   • Clinically significant stenosis: ≥ 50% narrowing.

   • Moderate stenosis: 50%–69% narrowing.

   • Severe stenosis: 70%–99% narrowing.

6. Stroke Risk Associated with Carotid Stenosis

   • Annual stroke rate: ~1% for 50-69% stenosis, 2-3% for 70-99% stenosis.

7. Diagnosis and Screening

   • No population-level screening recommendation.

   • Screening for high-risk individuals as per SVS guidelines.

   • Carotid Duplex Ultrasound as primary diagnostic tool.

   • Additional tools: CT angiography, Magnetic Resonance Angiography.

   • Handling of <50% stenosis cases. 

8. Imaging Modalities

   • Ultrasound: Noninvasive, cost-effective, potential overestimation of stenosis.

   • CTA: Fast, high resolution, contrast exposure risks.

   • MRA: Contrast-free plaque analysis, possible overestimation of stenosis.

   • Angiography: Gold standard, expensive, stroke risk. 

9. Assessing Degree of Stenosis via CDUS

   • Parameters for 50-69% stenosis: Peak Systolic Velocity (PSV) 125-229 cm/sec, End Diastolic Velocity (EDV) 40-100 cm/sec, Internal/Common Carotid peak systolic velocity Ratio 2-4.

   • Parameters for 70-99% stenosis: PSV ≥ 230 cm/sec, EDV > 100 cm/sec, Internal/Common Carotid peak systolic velocity Ratio > 4.

10. Revascularization Criteria

    • Symptomatic Patients: 50-69% or 70-99% stenosis, life expectancy at least three or two years, respectively.

    • Asymptomatic Patients: <50% stenosis, no revascularization; 50-69% stenosis, follow-up and surveillance; >70% stenosis, considering life expectancy.

11. Surgical Indications and Contraindications

    • Indications: symptomatic patients, life expectancy considerations.

    • Contraindications: Stenosis <50%, severe comorbidities, 100% occlusion.

12. Medical Management for All CAS Patients

    • Lifestyle changes, high-intensity statin therapy, antiplatelet therapy.

13. Decision Factors for Surgical Approaches

    • TCAR, stenting, endarterectomy: situational preferences.

14. Carotid Endarterectomy: Surgical Procedure

    • Incision along anterior border of sternocleidomastoid muscle.

    • Electrocautery through platysma muscle and subcutaneous tissues.

    • Protecting the great auricular nerve, dividing the external jugular vein.

    • Retracting sternocleidomastoid muscle, exposing carotid sheath.

    • Dissecting internal jugular vein, ligating facial vein.

    • Avoiding injury to the vagus nerve, dissecting the common carotid artery.

    • Identifying and mobilizing the hypoglossal nerve, addressing the external carotid artery.

    • Extending dissection from common carotid artery to beyond the internal and external carotid bifurcation.

    • Longitudinal arteriotomy, plaque removal using a Freer elevator.

    • Ensuring a smooth transition between endarterectomized artery and normal distal extent.

    • Patch angioplasty for arteriotomy closure, sequential clamp release for de-airing.

15. Neuromonitoring and Plaque Removal

    • Neuromonitoring methods: EEG, SSEPs, TCD, cerebral oximetry, awake patient monitoring.

16. Shunting and Vessel Closure

    • Shunting indications: neurological status changes, EEG alterations.

    • Carotid stump pressure measurement.

17. Postoperative Complications and Management

    • Common complications: stroke, hyperperfusion syndrome, myocardial infarction, cervical hematoma, nerve injuries, infection.

    • Managing hyperperfusion syndrome: blood pressure control, antiepileptic drugs.

    • Cranial nerve injuries: 

    • 1. Hypoglossal Nerve (CN XII): Injury leads to tongue deviation towards the injured side.

      2. Glossopharyngeal Nerve (CN IX): Injury results in swallowing difficulties and aspiration risk.

      3. Vagus Nerve (CN X): Injury causes hoarseness due to laryngeal muscle involvement.

      4. Marginal Mandibular Branch of Facial Nerve: Injury leads to ipsilateral lip droop.

 

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