Carotid Stenosis

Carotid stenosis can be symptomatic (e.g., cause of syncope or transient ischemic attack [TIA]/stroke) or asymptomatic (e.g., incidentally discovered during preoperative cardiac-surgery screening or as a carotid bruit on physical exam).

Diagnosis

The following table summarizes tests used to detect carotid stenosis:

[Image] — **Tests to Detect Carotid Stenosis**

Management

Carotid stenosis interventions:

Medical management for asymptomatic and symptomatic carotid stenosis includes cholesterol-lowering drugs (statins), blood pressure-lowering drugs, and antiplatelet agents.
- For symptomatic stenoses from 50% to 69%, medical management is usually preferred, although men may benefit more than women.
- Medical management and reduction of modifiable lifestyle factors should accompany surgical revascularization, and aspirin should be used prior to and after surgery.
Carotid endarterectomy (CEA) is major vascular surgery reserved for symptomatic and, rarely, high-grade asymptomatic carotid stenosis. It is the procedure of choice for most patients with carotid stenosis.
- The most common indication for CEA is in a patient with a symptomatic carotid lesion (e.g., history of ipsilateral TIA or ischemic stroke) and >70% stenosis.
- For symptomatic stenoses from 50% to 69%, men may benefit more than women, but medical management is usually preferred in both groups. (These recommendations were in part established by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) trial in 1991.)
- CEA is rarely considered in asymptomatic patients who are good operative candidates with high-grade stenosis. The 1995 Asymptomatic Carotid Atherosclerosis Study (ACAS) established that CEA reduced the risk of stroke by half in healthy patients with 60% stenosis or higher (read the NEJM Journal Watch summary). However, this benefit was only seen when performed at high-volume centers with low perioperative stroke risks, and therefore it is not commonly performed for asymptomatic indications.
- The NASCET and ACAS studies did not compare CEA to current optimal medical management. In practice, guidelines for CEA are changing with better medical management of carotid disease.
- Because the benefits of revascularization with CEA are often delayed, the patient’s life expectancy should be sufficiently longer to realize this benefit.
Carotid artery stenting (CAS) is an interventional procedure that is used for symptomatic and, rarely, high-grade asymptomatic carotid stenosis, including cases not amenable to CEA. CAS has emerged as an option based on two major trials:
- The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) study established safety and efficacy of CAS compared with CEA in patients <80 years of age. Read more about the CREST study in NEJM Journal Watch.
- The Asymptomatic Carotid Trial (ACT) I studied older patients (age 79 and older) with asymptomatic carotid stenosis of 70% to 99% who were at standard surgical risk and found that stenting was noninferior to endarterectomy in several outcomes, including stroke and death. (See the NEJM Journal Watch summary.)

Research

Landmark clinical trials and other important studies

Research

Comparative Effectiveness of Carotid Stenting to Medical Therapy Among Patients with Asymptomatic Carotid Stenosis

Keyhani S et al. Stroke 2022.

In an analysis of patients in the Veterans Affairs system with asymptomatic carotid stenosis using carotid imaging between 2005 and 2009 (219,979 patients, mean age 74, 99% men), the 5-year risk for stroke among those who underwent carotid artery stenting was 6.9%, a nonsignificant difference from the 7.1% risk observed among patients treated with medical therapy. The 5-year survival rate was 62% after carotid artery stenting and 67% with medical therapy.

Read the NEJM Journal Watch Summary

Screening for Asymptomatic Carotid Artery Stenosis in the General Population: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

Guirguis-Blake JM et al. JAMA 2021.

No eligible studies were identified that directly examined the benefits or harms of screening for asymptomatic carotid artery stenosis.

A Comparison of Two LDL Cholesterol Targets after Ischemic Stroke

Amarenco P et al. for the Treat Stroke to Target Investigators. N Engl J Med 2020.

This randomized trial evaluated ideal target LDL cholesterol values in patients following ischemic stroke.

Randomized Trial of Stent versus Surgery for Asymptomatic Carotid Stenosis

Rosenfield K et al for ACT I Investigators. N Engl J Med 2016.

The Asymptomatic Carotid Trial (ACT) I studied older patients (age 79 and older) with asymptomatic carotid stenosis of 70% to 99% who were at standard surgical risk and found that stenting was noninferior to endarterectomy in several outcomes, including stroke and death,

Long-Term Results of Stenting versus Endarterectomy for Carotid-Artery Stenosis

Brott TG et al. for the CREST Investigators. N Engl J Med 2016.

The CREST trial established the safety and efficacy of carotid artery stenting (CAS). Researchers compared carotid endarterectomy (CEA) to CAS in both symptomatic and asymptomatic patients with carotid stenosis. Ten-year rates of periprocedural and postprocedural stroke, myocardial infarction, or death were similar between the two groups.

Read the NEJM Journal Watch Summary

Endarterectomy for Asymptomatic Carotid Artery Stenosis

Walker MD et al. JAMA 1995.

The Asymptomatic Carotid Artery Stenosis (ACAS) trial is often referenced when deciding on treatment for asymptomatic carotid artery stenosis. Researchers randomized patients without prior history of stroke or transient ischemic attack (TIA) and with >60% carotid artery stenosis to medical therapy (daily aspirin plus risk-factor management) or medical therapy plus CEA. The aggregate 5-year risk for ipsilateral stroke, any perioperative stroke, or death was 5.1% for surgical patients and 11.0% for medically treated patients. Again, optimal medical care in this 1990 study differed from current management, and CEA was performed at centers with low perioperative morbidity rates.

Beneficial Effect of Carotid Endarterectomy in Symptomatic Patients with High-Grade Carotid Stenosis

North American Symptomatic Carotid Endarterectomy Trial Collaborators (NASCET). N Engl J Med 1991.

The NASCET trial is often referenced when discussing indications for CEA in patients with symptomatic carotid disease. This trial randomized patients with high-grade stenosis (70% to 99%) and recent cerebrovascular event to receive medical care (antiplatelet therapy and other medications as indicated) or CEA. At 2 years, cumulative risk of stroke was 26% in the medical care group and 9% in the surgical group. However, medical care in this 1991 study does not represent current medical therapy and surgery was performed in high-volume centers with low stroke-complication rates.

Read the NEJM Journal Watch Summary