Carotid Stenosis: Symptoms and Clinical Presentation
Carotid stenosis most commonly presents with transient ischemic attack (TIA), stroke, or amaurosis fugax (transient monocular blindness), though many patients remain asymptomatic until severe stenosis develops. 1
Symptomatic Presentations
Focal Neurologic Deficits
- Motor deficits including isolated paresis of the hand, arm, arm and face, or less commonly the leg, contralateral to the affected carotid artery 1
- Sensory deficits such as numbness or tingling affecting the same side of the body, opposite to the culprit carotid artery 1
- Speech disturbances including aphasia or dysarthria when the dominant hemisphere is affected 1
- TIA presents as focal neurologic deficits lasting <24 hours, while ischemic stroke involves symptoms persisting >24 hours 1
Visual Symptoms
- Amaurosis fugax (transient monocular blindness) caused by temporary reduction of blood flow to the ipsilateral eye 1, 2
- Retinal emboli may be detected during eye examinations, even in otherwise asymptomatic patients 1, 2
- Superior or inferior altitudinal visual field defects can occur from retinal arterial emboli 2
Specialized Presentations
- Limb-shaking TIA characterized by positive motor phenomena associated with hemodynamic impairment 1
- Low-flow TIA involving transient cerebral hypoperfusion due to severe stenosis 1
Critical Pitfall: Non-Attributable Symptoms
Isolated dizziness, headaches, transient global amnesia, acute confusion, syncope, isolated vertigo, nonrotational dizziness, bilateral weakness, and paresthesia should NOT be attributed to carotid stenosis. 1 These nonfocal neurological events require evaluation for alternative diagnoses including vestibular disorders, medication effects, cardiac arrhythmias, orthostatic hypotension, migraine, and tension headaches. 1
Stroke Risk Stratification
Symptomatic Stenosis
- Patients with TIA from carotid stenosis face approximately 6% stroke risk in the first year 1
- Carotid stenosis >50% is the strongest predictor of new vascular events after TIA 1
- For symptomatic patients with 70-79% stenosis: 19% stroke rate at 18 months without revascularization 1
- With 80-89% stenosis: 28% stroke rate at 18 months 1
- With 90-99% stenosis: 33% stroke rate at 18 months 1
Asymptomatic Stenosis
- Mean annual stroke rate of approximately 2% in asymptomatic patients with moderate stenosis 3
- Disease progression significantly increases stroke risk: 25% in patients with advancing disease versus 1% in those with stable lesions 3
Risk Factors and Clinical Correlations
- Hypertension, hypercholesterolemia, diabetes, and cigarette smoking increase subsequent stroke risk after TIA or amaurosis fugax 1
- Men tend to have larger plaques with more calcifications, lipid-rich necrotic cores, and intra-plaque hemorrhage compared to women 1
- Patients with six or more risk factors have 29% stroke rate versus 7% in those with five or fewer risk factors 3
Diagnostic Approach
Initial Imaging
- Duplex ultrasound is the first-line imaging modality to detect extracranial carotid stenosis and assess severity 1
- Peak systolic velocity in the internal carotid artery and the ratio to the ipsilateral common carotid artery correlate with angiographically determined stenosis 1
- Urgent imaging of the brain and supra-aortic vessels is mandatory in all patients presenting with TIA or stroke 1
High-Risk Plaque Features
Vulnerable plaques that increase stroke risk include: 1
- Increased plaque volume
- Ultrasound echolucency
- Inflammation and neovascularization
- Intra-plaque hemorrhage
- Ulcerations
- Lipid-rich necrotic cores
- Ruptured fibrous caps
Appropriate Indications for Carotid Evaluation
- Hemispheric TIA with focal deficits 1
- Amaurosis fugax 1
- Completed stroke in carotid territory 1
- Cervical bruit in asymptomatic patients 1
- Multiple atherosclerotic risk factors requiring vascular assessment 1
Treatment Overview
Symptomatic Stenosis (70-99%)
Carotid endarterectomy (CEA) should be performed within 14 days of symptom onset, ideally within the first few days after neurological stability, with documented perioperative stroke/death rates <6%. 4 The absolute risk reduction is substantial: 2-year ipsilateral stroke risk of 9% with CEA versus 26% with medical therapy alone. 4
Asymptomatic Stenosis (60-99%)
CEA may be considered only in highly selected patients with life expectancy >5 years and documented perioperative stroke/death rate <3%. 4 However, optimal medical therapy is mandatory for all patients, including dual antiplatelet therapy, high-intensity statin therapy, aggressive blood pressure control, smoking cessation, and diabetes management. 4