Carotid Artery Disease

CAD Basics & Anatomy - Neck's Vital Pipes

Carotid Artery Disease (CAD): Atherosclerotic plaque buildup causing stenosis (narrowing) of carotid arteries, mainly extracranial. Reduces cerebral blood flow, increasing TIA/stroke risk.

• Common Carotid Artery (CCA): Bifurcates at C3-C4 level into ICA & ECA.
• Internal Carotid Artery (ICA): Supplies brain (Circle of Willis). No neck branches.
  • Carotid Bulb/Sinus: Dilation at ICA origin; baroreceptors (CN IX), chemoreceptors (CN IX, X).
• External Carotid Artery (ECA): Supplies face, neck, scalp. Has neck branches.

⭐ The carotid bifurcation is the most common site for atherosclerotic plaque development.

Pathophysiology & Risks - Plaque Attack Central

• Atherosclerosis: Chronic inflammation from endothelial injury (e.g., at carotid bifurcation) → LDL influx, macrophage foam cells → fatty streak → fibrous plaque.
• Plaque Types:
  • Stable: Thick fibrous cap, small lipid core, less inflammation.
  • Vulnerable: Thin cap, large necrotic lipid core, ↑inflammation. Prone to rupture/ulceration → thromboembolism.
• Risk Factors:
  • Non-Modifiable: Age (>60), Male sex, Family history (genetics).
  • Modifiable: Hypertension (HTN), Diabetes Mellitus (DM), Hyperlipidemia (HLD), Smoking.

⭐ Hemorrhage into a plaque is a key event leading to acute symptoms.

Symptoms & Diagnosis - Stroke Alarms

• Presentation: Often asymptomatic. Symptomatic disease includes:

  • Transient Ischemic Attack (TIA): Focal deficit <24 hrs.
  • Amaurosis Fugax: Transient monocular blindness (ipsilateral ICA).
  • Reversible Ischemic Neurologic Deficit (RIND): Deficit >24 hrs, <3 weeks.
  • Stroke (CVA): Permanent deficit.
  • Clinical features depend on territory: e.g., contralateral weakness/sensory loss, aphasia.
  • 📌 FAST (Face, Arms, Speech, Time) for stroke recognition.

• Diagnostic Modalities:

  • Duplex Ultrasound (DUS): First-line, non-invasive. Grades stenosis (NASCET criteria). Intervention often considered for symptomatic >50% stenosis, or asymptomatic >70% stenosis.
  • CTA/MRA: Provide detailed anatomy, useful for surgical planning if DUS unclear or intervention planned.
  • DSA (Digital Subtraction Angiography): Gold standard, invasive. Reserved for equivocal cases or pre-intervention.

⭐ Amaurosis fugax (transient monocular blindness, often described as a "curtain falling") is a classic symptom of ipsilateral Internal Carotid Artery (ICA) disease.

Diagnostic Algorithm:

Comparison of Diagnostic Modalities:

Management Decisions - Scalpels or Stents

• Optimal Medical Therapy (OMT): Antiplatelets (Aspirin, Clopidogrel), Statins, BP control, Lifestyle modification.
• Intervention Thresholds (NASCET/ACAS/ACST criteria):
  • Symptomatic (TIA/Stroke): ≥70% stenosis; 50-69% (select: male, recent stroke).
  • Asymptomatic: ≥60% stenosis (select: low surgical risk, >5yr life expectancy).
• CEA steps: Open plaque removal, often patch angioplasty.

Prevention & Follow-Up - Keeping Pipes Clear

• Primary Prevention:
  • Aggressive risk factor modification: Control HTN, DM, dyslipidemia; smoking cessation.
• Secondary Prevention (Post-TIA/Stroke/Intervention):
  • Antiplatelet therapy (e.g., Aspirin, Clopidogrel).
  • High-intensity statin therapy.
• Post-Operative Care (CEA/CAS):
  • BP control (avoid hypo/hypertension).
  • Neuro checks (for stroke, nerve injury).
  • Wound care (hematoma, infection).
• Long-Term Surveillance:
  • Duplex Ultrasound: 1, 6, 12 months post-op, then annually to detect restenosis.

⭐ Dual antiplatelet therapy (DAPT) is often recommended for at least 30 days after Carotid Artery Stenting (CAS).

High‑Yield Points - ⚡ Biggest Takeaways

• Carotid bifurcation/proximal ICA: most common atherosclerotic site.
• Symptomatic patients (TIA, stroke) with >50% stenosis (NASCET) strongly benefit from revascularization.
• Asymptomatic patients: consider intervention for >60-70% stenosis, based on risk factors.
• Duplex ultrasound: initial diagnostic tool; DSA remains gold standard if needed.
• Carotid Endarterectomy (CEA): gold standard surgical treatment for suitable patients.
• Carotid Artery Stenting (CAS): alternative for high surgical risk or specific anatomies.
• Amaurosis fugax (transient monocular blindness): a critical warning sign.