Stenosis of the Carotid and Vertebral Arteries

Chapter: Stenosis of the Carotid and Vertebral Arteries
McMaster Section Editor(s): Wieslaw Oczkowski
Section Editor(s) in Interna Szczeklika: Andrzej Budaj, Wiktoria Leśniak
McMaster Author(s): Wieslaw Oczkowski
Author(s) in Interna Szczeklika: Wojciech Bodzoń, Marzena Frołow
Additional Information

Etiology, Pathogenesis, Clinical FeaturesTop

Atherosclerosis is the cause of >90% of all cases of stenosis or occlusion of the carotid arteries and most cases of stenosis of the vertebral arteries; rare causes include postradiotherapy stenosis, systemic vasculitis, spontaneous or traumatic artery dissection, and fibromuscular dysplasia. Carotid or vertebral artery stenosis may be symptomatic or asymptomatic.

1. Symptomatic carotid artery stenosis is defined as a transient ischemic attack (TIA) or stroke that has occurred within the prior 6 months in the vascular territory of the stenotic carotid artery. Neurologic symptoms may include:

1) Motor or sensory disturbances contralateral to the stenosis.

2) Speech disorder in the case of stenosis of the artery supplying the dominant hemisphere.

3) Inattention or neglect in the case of stenosis of the artery supplying the nondominant hemisphere.

3) Monocular visual disturbances ipsilateral to the stenosis (amaurosis fugax).

2. Symptomatic vertebral artery stenosis is defined as a TIA or stroke that has occurred in the vascular territory of the vertebrobasilar or posterior cerebral arteries. Neurologic symptoms may include:

1) Motor or sensory disturbances with cranial nerve involvement.

2) Crossed motor or sensory disturbances (face ipsilateral, arm and leg contralateral).

3) Gait ataxia especially if associated with limb ataxia or the symptoms and signs listed above.

DiagnosisTop

Auscultation for a carotid bruit is not sufficient to confirm or exclude carotid stenosis and should not be used for this purpose.Evidence 1Strong recommendation (downsides clearly outweigh benefits; right action for all or almost all patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to imprecision and indirectness. Ratchford EV, Jin Z, Di Tullio MR, et al. Carotid bruit for detection of hemodynamically significant carotid stenosis: the Northern Manhattan Study. Neurol Res. 2009 Sep;31(7):748-52. doi: 10.1179/174313209X382458. Epub 2009 Jan 7. PubMed PMID: 19133168; PubMed Central PMCID: PMC2727568.

Diagnostic Tests

Computed tomography (CT) or magnetic resonance imaging (MRI) of the brain should be done to identify cerebral infarction and to exclude hemorrhage. MRI is more sensitive for detecting ischemia than CT, especially in the posterior fossa. Color Doppler ultrasonography can accurately locate the atherosclerotic plaque, assess its morphology, and determine the severity of stenosis in carotid artery disease but not vertebral disease or intracranial disease. Magnetic resonance angiography (MRA) or computed tomography angiography (CTA) should be done to confirm the degree of stenosis and assess for vertebral or intracranial stenosis.Evidence 2Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to imprecision. Chappell FM, Wardlaw JM, Young GR, et al. Carotid artery stenosis: accuracy of noninvasive tests--individual patient data meta-analysis. Radiology. 2009 May;251(2):493-502. doi: 10.1148/radiol.2512080284. Epub 2009 Mar 10. PubMed PMID: 19276319. Because of the risk of complications, arteriography is reserved for situations when the severity or cause of stenosis cannot be assessed using other modalities.

TreatmentTop

Management algorithm in carotid artery stenosis: Figure. Management algorithm for carotid artery....

Medical Treatment

1. Management of risk factors for atherosclerosis: see Prevention of Cardiovascular Diseases. Use a statin in all patients, including those with asymptomatic stenosis. Make attempts to control diabetes mellitus. Smoking should be strongly discouraged.

2. Antiplatelet treatment: All patients should receive lifelong treatment with acetylsalicylic acid (ASA) 75 to 325 mg/d. If ASA is contraindicated, use clopidogrel 75 mg/d. For symptomatic intracranial disease, administer 2 antiplatelet agents for 90 days.Evidence 3Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to indirect comparison. Derdeyn CP, Chimowitz MI, Lynn MJ, et al; Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis Trial Investigators. Aggressive medical treatment with or without stenting in high-risk patients with intracranial artery stenosis (SAMMPRIS): the final results of a randomised trial. Lancet. 2014 Jan 25;383(9914):333-41. doi: 10.1016/S0140-6736(13)62038-3. Epub 2013 Oct 26. PubMed PMID: 24168957; PubMed Central PMCID: PMC3971471. Some physicians add clopidogrel 300 mg as a loading dose to ASA followed by 75 mg/d for 21 days in patients with a recent TIA or minor stroke and extracranial carotid disease (see Stroke). After endovascular angioplasty and stenting, our practice—acknowledging the lack of high-quality evidence to determine the duration of treatments—is to administer 2 antiplatelet agents for at least 30 days and ASA indefinitely.

Invasive Treatment

1. Carotid artery stenosis: Surgical removal of the atherosclerotic plaques that cause the stenosis (endarterectomy) or endovascular angioplasty with stent implantation. Treatment should be started as soon as possible after the symptomatic event to reduce the risk of recurrent stroke.Evidence 4Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to the risk of bias (subgroup analysis). Rothwell PM, Eliasziw M, Gutnikov SA, Warlow CP, Barnett HJ; Carotid Endarterectomy Trialists Collaboration. Endarterectomy for symptomatic carotid stenosis in relation to clinical subgroups and timing of surgery. Lancet. 2004 Mar 20;363(9413):915-24. PubMed PMID: 15043958. Endarterectomy is preferred over carotid artery stenting in older patients (eg, >75 years) to reduce the risk of periprocedural stroke.Evidence 5Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of the intervention). Antoniou GA, Georgiadis GS, Georgakarakos EI, et al. Meta-analysis and meta-regression analysis of outcomes of carotid endarterectomy and stenting in the elderly. JAMA Surg. 2013 Dec;148(12):1140-52. doi: 10.1001/jamasurg.2013.4135. Review. PubMed PMID: 24154858. Either treatment could be considered in younger patients. Endovascular treatment is, however, the treatment of choice for high-risk patients with any of the followingEvidence 6Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of the intervention). Yadav JS, Wholey MH, Kuntz RE, et al; Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy Investigators. Protected carotid-artery stenting versus endarterectomy in high-risk patients. N Engl J Med. 2004 Oct 7;351(15):1493-501. PubMed PMID: 15470212.:

1) Stenosis eligible for invasive treatment in a patient with general contraindications to surgery.

2) Severe cardiac or pulmonary disease.

3) Contralateral carotid occlusion.

4) Stenosis that is inaccessible to the surgeon for anatomical reasons.

5) Restenosis of the internal carotid artery after endarterectomy.

6) Postradiotherapy stenosis.

Medical management is usually preferred over a surgical or endovascular intervention for patients with asymptomatic carotid stenosis.Evidence 7Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to indirectness (relative lack of contemporary studies of the subject). Hart RG, Ng KH. Stroke prevention in asymptomatic carotid artery disease: revascularization of carotid stenosis is not the solution. Pol Arch Med Wewn. 2015;125(5):363-9. Epub 2015 Apr 17. PubMed PMID: 25883075.  Chambers BR, Donnan GA. Carotid endarterectomy for asymptomatic carotid stenosis. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD001923. Review. PubMed PMID: 16235289.

2. Vertebral or basilar artery stenosis: In patients with symptomatic or asymptomatic vertebral or basilar artery stenosis, dual antiplatelet treatment for 90 days after a neurologic event and single antiplatelet treatment indefinitely is recommended over invasive treatment.Evidence 8Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of the intervention). Derdeyn CP, Chimowitz MI, Lynn MJ, et al; Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis Trial Investigators. Aggressive medical treatment with or without stenting in high-risk patients with intracranial artery stenosis (SAMMPRIS): the final results of a randomised trial. Lancet. 2014 Jan 25;383(9914):333-41. doi: 10.1016/S0140-6736(13)62038-3. Epub 2013 Oct 26. PubMed PMID: 24168957; PubMed Central PMCID: PMC3971471. Antiplatelet treatment is recommended over anticoagulation in patients with symptomatic or asymptomatic vertebral or basilar stenosis.Evidence 9Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of the intervention). Chimowitz MI, Lynn MJ, Howlett-Smith H, et al; Warfarin-Aspirin Symptomatic Intracranial Disease Trial Investigators. Comparison of warfarin and aspirin for symptomatic intracranial arterial stenosis. N Engl J Med. 2005 Mar 31;352(13):1305-16. PubMed PMID: 15800226.

FiguresTop

Figure. Management algorithm for carotid artery stenosis. Adapted from the 2011 European Society of Cardiology guidelines (see Additional Information for details).

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