Definition
A.Atherosclerosis (waxy substance) plaque builds up inside the carotid arteries and causes carotid artery disease.
B.There are two common carotid arteries, one on each side of the neck. They each divide into internal and external carotid arteries.
1.The internal carotid arteries supply oxygen-rich blood to brain.
2.The external carotid arteries supply oxygen-rich blood to face, scalp, and neck.
Incidence
A.Carotid artery stenosis is one of the risk factors for stroke. The overall prevalence of asymptomatic carotid artery stenosis ≥ 50% in the general population is estimated.
B.The prevalence is higher in patients who harbor additional atherosclerotic lesions such as coronary artery disease.
C.Patients with severe asymptomatic carotid stenosis have an annual risk of 2% to 5% for stroke.
D.Among those 70 years and older, prevalence is increased to 12.5%.
Pathogenesis
A.Atherosclerosis of the carotid arteries is a diffuse, degenerative disease of the arteries resulting in plaques that consist of necrotic cells, lipids, and cholesterol crystals in the intima of carotid arteries.
B.Arterial narrowing leads to locally increased velocities. A hemodynamic effect is reached when pressure and flow volume are diminished in the poststenotic segment.
C.These plaques can cause stenosis, can crack, or cause injury, allowing platelets to stick to the site to form thrombi and/or rupture, causing embolization, which can cause stroke.
Predisposing Factors
A.Smoking.
B.High cholesterol levels in the blood.
C.High blood pressure.
D.Family history of atherosclerosis.
E.Sedentary lifestyle.
F.Diabetes or metabolic syndrome.
Subjective Data
A.Common complaints and symptoms.
1.Amaurosis fugax (fleeting or transient ipsilateral visual loss).
2.Transient ischemic attacks (TIAs).
3.Crescendo TIAs.
4.Stroke-in-evolution.
5.Cerebral infarction.
B.Common/typical scenario.
1.Patients may be asymptomatic with carotid artery disease.
2.Sometimes it is found on routine surveillance.
3.Patients oftentimes present with stroke symptoms which depend on the location of the brain.
4.Typically the patient with a stroke from carotid artery disease presents with weakness of extremities and speech difficulties.
C.Family and social history (pertinent findings—positive/negative).
1.Ask about family history, which has a strong association.
2.Ask about smoking, dietary habits, and physical activity.
D.Review of systems (pertinent findings—positive/negative).
1.Neurology—ask about the following:
a.Numbness.
b.Tingling or weakness.
c.Speech difficulties.
d.Confusion.
e.Trouble swallowing.
f.Visual disturbances.
Physical Examination
A.Thorough history.
B.Carotid bruit heard on auscultation.
C.Fundoscopic examination, if patient presents with amaurosis fugax, hypertensive, or history of TIAs.
D.Cardiac auscultation for murmur.
Diagnostic Tests
A.Imaging of the carotid artery is recommended in all patients with symptoms of carotid territory ischemia. This recommendation is based on the significant incidence of clinically relevant carotid stenosis in this patient group and the efficacy of carotid endarterectomy (CEA) for clinically significant lesions in reducing overall stroke (Grade 1, level of evidence A).
B.Imaging should be strongly considered for patients who present with amaurosis fugax, evidence of retinal artery embolization on fundoscopic examination, or asymptomatic cerebral infarction and are candidates for CEA. This recommendation is based on the intermediate stroke risk in this group of patients and the efficacy of CEA in reducing the risk of subsequent stroke (Grade 1, level of evidence A).
C.Routine screening is not recommended to detect clinically asymptomatic carotid stenosis in the general population.
D.Diagnosis.
1.Carotid duplex ultrasonography, with or without color: Screening test of choice to evaluate for carotid stenosis.
2.Computed tomographic angiography (CTA) is preferable to MRI/magnetic resonance angiography (MRA) for delineating calcium.
3.Carotid angiography.
4.Carotid MRA: May be useful in collaborating the finding of an occluded carotid with duplex sonography; however, this modality tends to overstate the significance of the stenosis.
5.Aortic arch and carotid arteriography: To evaluate the percentage of stenosis.
Differential Diagnosis
A.Stroke.
B.Intracerebral hemorrhage.
C.Neck trauma.
D.Headache.
E.Vertebral dissection.
F.Vertigo.
Evaluation and Management Plan
A.General plan.
1.For neurologically symptomatic patients with 50% stenosis or asymptomatic patients with 60% stenosis diameter reduction, optimal medical therapy is indicated (Grade 1, level of evidence B).
a.Grading carotid artery stenosis by ultrasound.
i.Low degree stenosis 0% to 40%.
ii.Moderate stenosis 50% to 60%.
iii.Hemodynamically relevant stenosis greater than 70%.
iv.Other simplistic grade is mild stenosis (less than 50%), moderate stenosis (50%–70%), and severe stenosis (70% or greater).
2.Antiplatelet therapy in asymptomatic patients with carotid atherosclerosis is recommended to reduce overall cardiovascular morbidity although it has not been shown to be effective in the primary prevention of stroke.
3.Surgical management.
a.Carotid artery angioplasty and stenting.
i.Indication for carotid angioplasty and stenting (CAS).
1)Symptomatic patients with a high-grade stenosis (>70%) who are at high risk for CEA.
2)Patients who are at high risk for CEA and have asymptomatic carotid stenosis greater than 80%.
3)CAS is preferred over CEA in symptomatic patients with 50% stenosis and prior ipsilateral operation, tracheal stoma, or external beam irradiation resulting in fibrosis of the tissues of the ipsilateral neck.
b.CEA.
i.Indications for CEA.
1)Symptomatic patients with greater than 70% stenosis—clear benefit was found in the North American Symptomatic Carotid Endarterectomy Trial (NASCET).
2)Symptomatic patients with greater than 50% to 69% stenosis—benefit is marginal; appears to be greater for male patients.
3)Asymptomatic patients with greater than 60% stenosis—benefit is significantly less than for symptomatic patients with greater than 70% stenosis.
4)Generally, symptomatic patients with greater than 50% stenosis and healthy, asymptomatic patients with greater than 60% stenosis warrant consideration for CEA.
5)Patients who present with repetitive (crescendo) episodes of transient cerebral ischemia unresponsive to antiplatelet therapy should be considered for urgent CEA.
6)CEA is preferred over CAS in patients 70 years of age, with long (>15 mm) lesions, preocclusive stenosis, or lipid-rich plaques that can be completely removed safely by a cervical incision in patients who have a virgin, nonradiated neck.
7)Patients with symptomatic carotid stenosis will benefit from CEA prior to or concomitant with coronary artery bypass graft. The timing of the intervention depends on clinical presentation and institutional experience.
8)Patients with severe bilateral asymptomatic carotid stenosis (including stenosis and contralateral occlusion) should be considered for CEA prior to or concomitant with coronary artery bypass graft.
ii.Contraindications for CEA.
1)Patients with a severe neurological deficit following a cerebral infarction.
2)Patients with an occluded carotid artery.
3)Concurrent medical illness that would significantly limit the patient’s life expectancy.
4)Anatomic issues that would be unfavorable for CEA include the following:
a)Lesions that extend above C2.
b)Prior irradiation of the neck.
c)Prior neck operation.
B.Patient/family teaching points.
1.Review lifestyle changes.
a.Smoking cessation.
b.Weight loss.
c.Increasing physical activity.
d.Consuming a healthy diet low in fat and cholesterol.
2.Remind patients to take medication daily.
3.Blood pressure management.
4.Optimum blood sugar control in diabetes.
5.Manage comorbid conditions.
6.Educate patient on warning for stroke and regular follow-up.
7.Patients should be instructed to seek help immediately if they have any worsening symptoms or signs and symptoms of a stroke.
C.Pharmacotherapy.
1.Perioperative medical management of patients undergoing carotid revascularization should include blood pressure control (<140/80) or beta-blockade (HR 60–80).
2.Management of cholesterol with statin therapy (low-density lipoprotein [LDL] 100 mg/dL).
3.Perioperative antithrombotic therapy for CEA should include aspirin (81–325 mg).
a.Antiplatelet agents (e.g., aspirin, ticlopidine, clopidogrel).
b.Anticoagulants (e.g., warfarin)—Note that use of warfarin in patients with noncardiac emboli is controversial. Anticoagulation is not recommended for the treatment of TIA or acute stroke unless there is evidence of a cardioembolic source.
D.Discharge instructions.
1.Eat a healthy diet.
2.Limit salt.