Atherosclerotic Disease of the Carotid Artery 

  • Author: Niten Singh, MD; Chief Editor: Vincent Lopez Rowe, MD   more...
 
Updated: Oct 14, 2011
 

Background

Atherosclerosis is a degenerative disease of the arteries resulting in plaques consisting of necrotic cells, lipids, and cholesterol crystals. These plaques can result in symptoms by causing a stenosis, embolizing, and thrombosing. Atherosclerosis is a diffuse process with a predilection for certain arteries. This article describes the history and impact of this process as it occurs in the extracranial carotid artery.

An image depicting the carotid artery can be seen below.

Arteriogram of the aortic arch and its branches. Arteriogram of the aortic arch and its branches.
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History of the Procedure

The ancient Greeks recognized the importance of the extracranial carotid artery and named it from the Greek word karoo, which means to stupefy. In 1875, Growers described a patient with right hemiplegia that he attributed to an occluded left carotid artery. In 1914, Hunt emphasized the relationship between extracranial carotid disease and stroke using the phrase cerebral intermittent claudication. The surgical management of stroke was suggested in 1951 by Fisher who stated the following: "It is even conceivable that some day vascular surgery will find a way to bypass the occluded portion of the artery during the period of ominous fleeting symptoms."

The initial report of a successful surgical resection of a carotid plaque and primary anastomosis came from Eastcott, Pickering, and Rob in 1954. In 1975, DeBakey reported the 19-year follow-up of a carotid endarterectomy, the current procedure used to surgically manage atherosclerotic disease of the carotid bulb.

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Problem

Stroke from any cause represents the third leading cause of death in the United States. Half a million new strokes occur each year in the United States, resulting in approximately 150,000 deaths. Stroke is the leading cause of serious long-term disability in the United States. Direct and indirect cost of stroke in the United States in 1997 was estimated at $40 billion.

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Epidemiology

Frequency

Incidence of new stroke is approximately 160 cases per 100,000 population per year. The incidence and mortality rate of stroke have reached a plateau over the past 10 years.

The risk of stroke increases with age, hypertension, the presence of a carotid bruit, diabetes, smoking, atrial fibrillation, obesity, hyperlipidemia, and elevated homocysteine level.

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Etiology

Ninety percent of all extracranial carotid lesions are due to atherosclerosis.

The exact cause of atherosclerosis is unknown, and it may be the result of multiple etiologies. This concept has been referred to as the response to injury hypothesis. Infectious agents, hypertension, hyperlipidemia, and cigarette smoking have been cited as potential causes of atherosclerosis.

Other etiologies for carotid lesions include the following:

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Pathophysiology

Currently, embolization is considered the most common mechanism causing ischemic strokes from atherosclerotic lesions in the carotid bulb. Thrombosis and low flow are other possible mechanisms.

Stroke is one of the most devastating complications of carotid stenosis. However, carotid stenosis is not the only cause of stroke. In fact, consider that 45% of strokes in patients with asymptomatic stenosis of 60-99% may be caused by lacunar infarcts or cardiac emboli.

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Presentation

  • Amaurosis fugax (transient visual loss)
  • Transient ischemic attacks (TIAs)
  • Crescendo TIAs
  • Stroke-in-evolution
  • Cerebral infarction
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Indications

The following are indications for carotid endarterectomy based on prospective randomized trials:

  • Symptomatic patients with greater than 70% stenosis: Clear benefit was found in the North American Symptomatic Carotid Endarterectomy Trial (NASCET); ipsilateral stroke in 2 years was 9% with surgery and 26% with medical management.[1]
  • Symptomatic patients with greater than 50-69% stenosis: Benefit is marginal and appears to be greater for male patients.
  • Asymptomatic patients with greater than 60% stenosis: Benefit is significantly less than symptomatic patients with greater than 70% stenosis.

Note

  • Available literature includes considerable overlap in the percent of stenosis used as the threshold for carotid endarterectomy. In general, symptomatic patients with greater than 50% stenosis and healthy, asymptomatic patients with greater than 60% stenosis warrant consideration for carotid endarterectomy.
  • Symptomatic trials include patients with TIAs or minor strokes within 3 months of entry.
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Relevant Anatomy

The carotid artery on the right originates from the innominate artery and on the left directly from the aortic arch. The carotid artery enlarges in the mid neck, forming the carotid bulb. It then bifurcates into the external and internal carotid arteries. The carotid sinus and carotid body are located at the bifurcation (see the image below).

Arteriogram of the aortic arch and its branches. Arteriogram of the aortic arch and its branches.
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Contraindications

Contraindications to carotid endarterectomy include the following:

  • Patients with a severe neurologic deficit following a cerebral infarction
  • Patients with an occluded carotid artery
  • Concurrent medical illness that would significantly limit the patient's life expectancy
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Contributor Information and Disclosures
Author

Niten Singh, MD  Assistant Professor of Surgery, Uniformed Services University of the Health Sciences; Chief of Endovascular Surgery, Madigan Army Medical Center

Niten Singh, MD is a member of the following medical societies: American College of Surgeons, American Medical Association, and Society for Vascular Surgery

Disclosure: Nothing to disclose.

Coauthor(s)

Sean D O'Donnell, MD  Director, Department of Surgery, Section of Vascular and Endovascular Surgery, Washington Hospital Center

Sean D O'Donnell, MD is a member of the following medical societies: American College of Surgeons and Association of Military Surgeons of the US

Disclosure: Nothing to disclose.

David L Gillespie, MD, FACS, RVT, DMCC, COL, MC  USA Chief and Program Director, Vascular Surgery Service, Walter Reed Army Medical Center; Professor of Surgery, Uniformed Services University of the Health Sciences; Vascular Surgery Consultant, Office of the US Army Surgeon General

David L Gillespie, MD, FACS, RVT, DMCC, COL, MC is a member of the following medical societies: Alpha Omega Alpha, American College of Surgeons, American Venous Forum, Eastern Vascular Society, Society for Vascular Surgery, and Southern Association for Vascular Surgery

Disclosure: Nothing to disclose.

James M Goff, MD  Assistant Chief, Department of Surgery, Walter Reed Army Medical Center; Assistant Professor, F Department of Surgery, F Edward Hebert School of Medicine, Uniformed Services University of the Health Sciences

James M Goff, MD is a member of the following medical societies: American College of Surgeons

Disclosure: Nothing to disclose.

Specialty Editor Board

Richard M Stillman†, MD, FACS  Honorary Medical Staff, Northwest Medical Center; Former Chief of Staff and Medical Director, Wound Healing Center, Department of Surgery, Northwest Medical Center

Richard M Stillman†, MD, FACS is a member of the following medical societies: American College of Angiology, American College of Surgeons, Association for Academic Surgery, and Society of University Surgeons

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Vincent Lopez Rowe, MD  Associate Professor of Surgery, Department of Surgery, Division of Vascular Surgery, University of Southern California Medical Center

Vincent Lopez Rowe, MD is a member of the following medical societies: American College of Surgeons, American Heart Association, Pacific Coast Surgical Association, Peripheral Vascular Surgery Society, Society for Clinical Vascular Surgery, Society for Vascular Surgery, and Western Vascular Surgical Society

Disclosure: Nothing to disclose.

Paolo Zamboni, MD  Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy

Paolo Zamboni, MD is a member of the following medical societies: American Venous Forum and New York Academy of Sciences

Disclosure: Nothing to disclose.

Chief Editor

Vincent Lopez Rowe, MD  Associate Professor of Surgery, Department of Surgery, Division of Vascular Surgery, University of Southern California Medical Center

Vincent Lopez Rowe, MD is a member of the following medical societies: American College of Surgeons, American Heart Association, Pacific Coast Surgical Association, Peripheral Vascular Surgery Society, Society for Clinical Vascular Surgery, Society for Vascular Surgery, and Western Vascular Surgical Society

Disclosure: Nothing to disclose.

References

  1. North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. Aug 15 1991;325(7):445-53. [Medline].

  2. Canadian Cooperative Study Group. A randomized trial of aspirin and sulfinpyrazone in threatened stroke. The Canadian Cooperative Study Group. N Engl J Med. Jul 13 1978;299(2):53-9. [Medline].

  3. Halliday A, Mansfield A, Marro J, et al. Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial. Lancet. May 8 2004;363(9420):1491-502. [Medline].

  4. Mas JL, Trinquart L, Leys D, et al. Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis (EVA-3S) trial: results up to 4 years from a randomised, multicentre trial. Lancet Neurol. Oct 2008;7(10):885-92. [Medline].

  5. Brott TG, Hobson RW 2nd, Howard G, et al. Stenting versus endarterectomy for treatment of carotid-artery stenosis. N Engl J Med. Jul 1 2010;363(1):11-23. [Medline]. [Full Text].

  6. Centers for Medicare and Medicaid Services. Available at www.cms.hhs.gov.

  7. [Best Evidence] Meier P, Knapp G, Tamhane U, Chaturvedi S, Gurm HS. Short term and intermediate term comparison of endarterectomy versus stenting for carotid artery stenosis: systematic review and meta-analysis of randomised controlled clinical trials. BMJ. Feb 12 2010;340:c467. [Medline].

  8. Illuminati G, Ricco JB, Caliò F, et al. Short-term results of a randomized trial examining timing of carotid endarterectomy in patients with severe asymptomatic unilateral carotid stenosis undergoing coronary artery bypass grafting. J Vasc Surg. Oct 2011;54(4):993-9. [Medline].

  9. Young B, Moore WS, Robertson JT, et al. An analysis of perioperative surgical mortality and morbidity in the asymptomatic carotid atherosclerosis study. ACAS Investigators. Asymptomatic Carotid Artheriosclerosis Study. Stroke. Dec 1996;27(12):2216-24. [Medline].

  10. Wiesmann M, Schopf V, Jansen O, et al. Stent-protected angioplasty versus carotid endarterectomy in patients with carotid artery stenosis: meta-analysis of randomized trial data. Eur Radiol. Dec 2008;18(12):2956-66. [Medline].

  11. Barnett HJ, Taylor DW, Eliasziw M, et al. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. Nov 12 1998;339(20):1415-25. [Medline].

  12. Burton KR, Lindsay TF. Assessment of short-term outcomes for protected carotid angioplasty with stents using recent evidence. J Vasc Surg. Dec 2005;42(6):1094-100. [Medline].

  13. Endovascular versus surgical treatment in patients with carotid stenosis in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS): a randomised trial. Lancet. Jun 2 2001;357(9270):1729-37. [Medline].

  14. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. Endarterectomy for asymptomatic carotid artery stenosis. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. JAMA. May 10 1995;273(18):1421-8. [Medline].

  15. Friedman SG. A History of Vascular Surgery. Mount Kisco, NY: Futura Publishing Co; 1989.

  16. Gurm HS, Yadav JS, Fayad P, et al. Long-term results of carotid stenting versus endarterectomy in high-risk patients. N Engl J Med. Apr 10 2008;358(15):1572-9. [Medline].

  17. Hobson RW 2nd. Status of carotid angioplasty and stenting trials. J Vasc Surg. Apr 1998;27(4):791. [Medline].

  18. Hobson RW 2nd, Goldstein JE, Jamil Z, et al. Carotid restenosis: operative and endovascular management. J Vasc Surg. Feb 1999;29(2):228-35; discussion 235-8. [Medline].

  19. Inzitari D, Eliasziw M, Gates P, et al. The causes and risk of stroke in patients with asymptomatic internal-carotid-artery stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. Jun 8 2000;342(23):1693-700. [Medline].

  20. Jackson MR, Chang AS, Robles HA, et al. Determination of 60% or greater carotid stenosis: a prospective comparison of magnetic resonance angiography and duplex ultrasound with conventional angiography. Ann Vasc Surg. May 1998;12(3):236-43. [Medline].

  21. Liapis C, Kakisis J, Papavassiliou V, et al. Hemostatic function and carotid artery disease. Int Angiol. Mar 2004;23(1):14-7. [Medline].

  22. Moore WS. Fundamental Considerations in Cerebrovascular Disease. In: Rutherford Vascular Surgery. 5th ed. Philadelphia, Pa: WB Saunders; 2000:1713-30.

  23. [Best Evidence] Ringleb PA, Allenberg J, Bruckmann H, et al. 30 day results from the SPACE trial of stent-protected angioplasty versus carotid endarterectomy in symptomatic patients: a randomised non-inferiority trial. Lancet. Oct 7 2006;368(9543):1239-47. [Medline].

  24. Wakhloo AK, Lieber BB, Seong J, et al. Hemodynamics of carotid artery atherosclerotic occlusive disease. J Vasc Interv Radiol. Jan 2004;15(1 Pt 2):S111-21. [Medline].

  25. Yadav JS, Wholey MH, Kuntz RE, et al. Protected carotid-artery stenting versus endarterectomy in high-risk patients. N Engl J Med. Oct 7 2004;351(15):1493-501. [Medline].

 
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Arteriogram of the aortic arch and its branches.
Arteriogram of a carotid stenosis.
Atherosclerotic plaque removed at the time of carotid endarterectomy (areas of ulceration with thrombus and intraplaque hemorrhage present).
Carotid artery exposed prior to carotid endarterectomy (coil present in the internal carotid artery).
Carotid artery following endarterectomy and prior to closure (tapered endpoint and smooth appearance of the lumen).
Carotid artery following Dacron patch angioplasty.
Selective left carotid angiogram.
Oblique view of the left carotid artery demonstrating lesion within internal carotid artery.
Placement of stent into internal carotid artery. Note filter wire in upper photos (dots at top of internal carotid artery).
Angioplasty after stent placement; again, note filter wire protecting distal carotid artery.
Completion arteriogram displaying improvement in diameter of internal carotid artery.
Normal carotid arteries on color flow duplex.
Color flow duplex revealing an 80-99% left carotid stenosis and a normal right carotid.
Carotid plaque.
 
 
 
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