Carotid stenosis may be caused by atherosclerosis, intimal fibroplasia, vasculitis, adventitial cysts, or vascular tumors; atherosclerosis is the most common etiology.
- Narrowing of the carotid artery lumen is typically due to atherosclerotic changes in the vessel wall. Atherosclerotic plaques are responsible for 90% of extracranial carotid lesions and up to 30% of all ischemic strokes.
- A “hemodynamically significant” carotid stenosis produces a drop in pressure or a reduction in flow. It corresponds approximately to a 60–99% diameter-reducing stenosis.
- Carotid lesions are classified by the following:
- Symptom status
- Asymptomatic: tend to be homogenous and stable
- Symptomatic: tend to be heterogeneous and unstable; present with stroke or transient cerebral ischemic attack
- Degree of stenosis
- High grade: 80–99% stenosis
- Moderate grade: 50–79% stenosis
- Low grade: <50% stenosis
- Symptom status
More common in men and with increasing age (see “Risk Factors”)
Unclear (Asymptomatic patients often go undiagnosed.)
- Moderate stenosis
- Age <50 years: men 0.2%, women 0%
- Age >80 years: men 7.5%, women 5%
- Severe stenosis
- Age <50 years: men 0.1%, women 0%
- Age >80 years: men 3.1%, women 0.9%
Etiology and Pathophysiology
- Atherosclerosis begins during adolescence, consistently at the carotid bifurcation. The carotid bulb has unique blood flow dynamics. Hemodynamic disturbances cause endothelial injury and dysfunction. Plaque formation in vessel wall results and stenosis then ensues.
- Initial cause is not well understood, but certain risk factors are frequently present (see “Risk Factors”). Tensile stress on the vessel wall, turbulence, and arterial wall shear stress seem to be involved.
- Increased incidence among family members
- Genetically linked factors
- Diabetes mellitus (DM), race, hypertension (HTN), family history, obesity
- In a recent single nucleotide polymorphism study, the following genes were strongly associated with worse carotid plaque: TNFSF4, PPARA, TLR4, ITGA2, and HABP2.
- Nonmodifiable factors: advanced age (>65 years old), male sex, family history, coronary artery disease (CAD), peripheral artery disease, aortic aneurysmal disease, congenital arteriopathies
- Modifiable factors: smoking, diet, dyslipidemia, physical inactivity, obesity, HTN, DM
- Possible factors: Chlamydia pneumoniae and Cytomegalovirus
- Antihypertensive treatment to maintain BP <140/90 mm Hg (systolic BP of 150 mm Hg is target in elderly). See “Hypertension, Essential.”
- Smoking cessation to reduce the risk of atherosclerosis progression and stroke
- Lipid control: regression of carotid atherosclerotic lesions seen with statin therapy
Commonly Associated Conditions
- Transient ischemic attack (TIA)/stroke
- CAD/myocardial infarction (MI)
- Peripheral vascular disease (PVD)
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Domino, Frank J., et al., editors. "Carotid Stenosis." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688701/all/Carotid_Stenosis.
Carotid Stenosis. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688701/all/Carotid_Stenosis. Accessed May 27, 2023.
Carotid Stenosis. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688701/all/Carotid_Stenosis
Carotid Stenosis [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 May 27]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688701/all/Carotid_Stenosis.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Carotid Stenosis ID - 1688701 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688701/all/Carotid_Stenosis PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -