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.

1. 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.

1. 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.

1. Importance of Evaluating CAS

   • Assessing stenosis severity and stroke risk.

   • Revascularization benefits dependent on stenosis severity.

1. Classification of Stenosis Levels

   • Clinically significant stenosis: ≥ 50% narrowing.

   • Moderate stenosis: 50%–69% narrowing.

   • Severe stenosis: 70%–99% narrowing.

1. Stroke Risk Associated with Carotid Stenosis

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

1. 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.

1. 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.

1. 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.

1. 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.

1. Surgical Indications and Contraindications

   • Indications: symptomatic patients, life expectancy considerations.

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

1. Medical Management for All CAS Patients

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

1. Decision Factors for Surgical Approaches

   • TCAR, stenting, endarterectomy: situational preferences.

1. 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.

1. Neuromonitoring and Plaque Removal

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

1. Shunting and Vessel Closure

   • Shunting indications: neurological status changes, EEG alterations.

   • Carotid stump pressure measurement.

1. 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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