The objective of carotid endarterectomy (CEA) is to prevent strokes. In the United States, stroke is the fifth leading cause of death overall, and women have a higher lifetime risk of stroke than men do. Among patients suffering a stroke, 50-75% had carotid artery disease that would have been amenable to surgical treatment.
Several prospective randomized trials have compared the safety and efficacy of CEA with those of medical therapy in symptomatic and asymptomatic patients.
Data from these prospective trials have confirmed that CEA offers better protection from ipsilateral strokes than medical therapy alone in patients presenting with either symptomatic or asymptomatic carotid artery disease.
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| Carotid Endarterectomy |
Indications
CEA should be considered for any patient with carotid artery stenosis in whom surgery will improve the natural history of the disease to a greater degree than the corresponding medical treatment would.In symptomatic good-risk patients with surgical morbidity and mortality (stroke and death) of less than 6%, proven indications for CEA include the following:
One or more transient ischemic attacks (TIAs) in the preceding 6 months and carotid artery stenosis exceeding 50% [4]
Acceptable but not proven indications include the following:
Ipsilateral TIA and carotid artery stenosis exceeding 70%, combined with required coronary artery bypass grafting (CABG)
Progressive stroke and carotid artery stenosis exceeding 70%
In asymptomatic good-risk patients treated by surgeons with surgical mortality and morbidity of less than 3%, the proven indication for CEA is stenosis exceeding 60%.
The 2014 American Heart Association (AHA)/American Stroke Association (ASA) guidelines for the prevention of stroke in patients with stroke or TIA contained the following new or updated recommendations relevant to CEA:
Carotid angioplasty and stenting (CAS) is indicated as an alternative to CEA for symptomatic patients at average or low risk for complications associated with endovascular intervention when the diameter of the lumen of the internal carotid artery is reduced by >70% by noninvasive imaging or >50% by catheter-based imaging or noninvasive imaging with corroboration and the anticipated rate of periprocedural stroke or death is < 6% (class IIa; evidence level B)
It is reasonable to consider patient age in choosing between CAS and CEA; for patients older than about 70 years, CEA may be associated with improved outcome CAS, particularly when the arterial anatomy does not favor endovascular intervention; for younger patients, CAS is equivalent to CEA in terms of risk for periprocedural complications and long-term risk for ipsilateral stroke (class IIa; evidence level B)
CAS and CEA in the above settings should be performed by operators with established periprocedural stroke and mortality rates of < 6% for symptomatic patients (class I; evidence level B)
Routine, long term follow-up imaging of the extracranial carotid circulation with carotid duplex ultrasonography is not recommended (class III; evidence level B)
Contraindications
CEA is contraindicated if the patient’s general condition includes a serious illness that will substantially increase perioperative risk or shorten life expectancy. It is also contraindicated in patients who present acutely with a major stroke or in patients who experienced a major devastating stroke with minimal recovery or a significantly altered level of consciousness.
The traditional teaching was that emergency CEA in an acutely occluded carotid artery might convert an ischemic cerebral infarct to a hemorrhagic infarct, possibly resulting in death. The timing of the operation was considered optimal when the patient reached optimal recovery before elective CEA was performed. However, a few reports of improved neurologic outcomes with early intervention in patients with acute nonhemorrhagic strokes have emerged. Careful patient selection is essential.
In a study of perioperative and long-term outcomes after CEA in hemodialysis patients, Cooper et al found that the risks of CEA in asymptomatic dialysis-dependent patients were high, possibly outweighing the benefits. [8] They also found the risk to be high in symptomatic patients and suggested that it should be offered only to a small and carefully selected cohort of these patients.
Technical Considerations
A solid understanding of the anatomy of the carotid vessels and adjacent structures (see the image below) is critical for performing CEA effectively and minimizing complications.The aortic arch provides the great vessels, including the innominate artery, the left common carotid artery (CCA), and the subclavian artery. In the most common configuration, the innominate artery branches into the right subclavian artery and the right CCA. Vertebral arteries branch off the subclavian arteries bilaterally.
On each side, the CCA travels within the carotid sheath before branching into the ipsilateral internal carotid artery (ICA) and external carotid artery (ECA). The ECA primarily supplies blood to the face and includes branches of the superior thyroid and ascending pharyngeal arteries. The ICA has no extracranial branches.
The carotid sinus is a baroreceptor located at the carotid bifurcation (where the CCA bifurcates into the ICA and the ECA) and is innervated by the nerve of Hering, a branch from cranial nerve IX (the glossopharyngeal nerve). The carotid bifurcation also contains the carotid body, which functions as a chemoreceptor responding to low oxygen levels or high carbon dioxide levels.
The ICA has an intracranial branch called the ophthalmic artery, which collateralizes and communicates with the external carotid blood supply. The ophthalmic artery is a common location for carotid emboli, which may result in transient monocular blindness (TMB) if they dissolve quickly or central retinal artery occlusion and blindness if they do not. The intracranial circle of Willis provides further communication between the ICA, the ECA, and the vertebrobasilar system.
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