Atherosclerotic Disease of the Carotid Artery Treatment & Management
- Author: April L Rodriguez, MD, MS; Chief Editor: Vincent Lopez Rowe, MD more...
Risk Factor Modification
Lifestyle or medical interventions are implemented in order to address the following risk factors:
Aspirin (30-1350 mg/day) irreversibly acetylates the cyclooxygenase of platelets, thus inhibiting platelet synthesis of thromboxane A2. Prostacyclin production in the endothelium is reduced, but this effect is reversible and short-lived. A reduction in transient ischemic attacks (TIAs), stroke, and death in men was shown in the Canadian Cooperative Study Group.
Ticlopidine (250 mg q12hr) is a thienopyridine that irreversibly alters the platelet membrane and inhibits platelet aggregation. It is approximately 10% more effective than aspirin. Toxicity includes neutropenia and diarrhea. Clopidogrel (75 mg/day) is similar to ticlopidine; the risk of neutropenia is low.
Warfarin (titrated international normalized ratio [INR] 2-3) use in patients with noncardiac emboli is controversial.
The following are indications for carotid endarterectomy (CEA), 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); the incidence of ipsilateral stroke in 2 years was 9% with surgery and 26% with medical management 
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 for symptomatic patients with greater than 70% stenosis
Available literature includes considerable overlap in the percent of stenosis used as the threshold for CEA; in general, symptomatic patients with greater than 50% stenosis and healthy, asymptomatic patients with greater than 60% stenosis warrant consideration for CEA
Symptomatic trials include patients with transient ischemic attacks (TIAs) or minor strokes within 3 months of entry
Contraindications for CEA include the following:
Patients with a severe neurologic deficit after a cerebral infarction
Patients with an occluded carotid artery
Concurrent medical illness that would significantly limit the patient’s life expectancy
For the indications listed above, medical management was found to be inferior to CEA.
Patients with carotid artery stenosis have a high incidence of concomitant coronary artery disease (CAD). American Heart Association (AHA) recommendations regarding cardiac evaluation for noncardiac surgery should therefore be adhered to. In brief, the AHA recommends a functional assessment be performed on all patients with a history of new-onset angina and new symptoms following coronary angioplasty or bypass.
Nondiabetic patients younger than 70 years with no cardiac symptoms and normal findings on electrocardiography (ECG) may undergo CEA without further cardiac workup.
Preoperative imaging studies
Imaging studies should be performed preoperatively used to determine the extent of stenosis and to evaluate for kinks and coils that may affect the conduct of the operation (see Workup). Many surgeons who work with certified laboratories proceed with surgery on the basis of carotid duplex ultrasonography alone. If any doubt exists regarding the degree of stenosis or the distal extent of the disease, arteriography of the arch and the carotid is indicated.
The extent of the disease should also be noted, with particular attention to the superior extent of the stenosis. The superior disease extent may influence the type of anesthesia chosen, and additional measures may prove necessary to expose an unusually high lesion.
Anatomic issues that would be unfavorable for CEA include the following:
Lesions that extend above C2
Prior irradiation of the neck
Prior neck operation
Local anesthesia has the advantage of allowing direct evaluation of the patient’s neurologic status without sophisticated monitoring. This enables the surgeon to operate on most patients without the need for a shunt, which is a technical nuisance and may pose an increased risk of stroke to the patient.
General anesthesia has the advantage of improved airway control and patient comfort during prolonged operations. However, it does require the use of routine or selected shunting, and selective shunting requires the use of electroencephalography (EEG), stump pressures, and transcranial Doppler or some other form of cerebral monitoring to assess the need for a shunt.
A vertical incision is made along the anterior border of the sternocleidomastoid. An oblique incision is made in the skin fold over the carotid bifurcation. (See the image below.)
The endarterectomy is carried out in a smooth plane in the media of the artery. The most important aspect of this portion of the procedure is to obtain a smooth, tapering endpoint on the internal carotid (see the image below). Occasionally, tacking sutures are required to accomplish this.
The endarterectomy is closed either primarily or with a patch (see the image below). The technical result should be verified by means of completion angiography or duplex ultrasonography.
Postoperatively, a complete blood count is obtained, electrolyte concentrations assessed, and ECG performed. Hemodynamic monitoring is instituted, with a focus on maintaining the patient’s blood pressure at its preoperative range. The patient is observed for the formation of a hematoma that may compromise the airway. Antiplatelet therapy is necessary.
Patients are evaluated 2 weeks postoperatively for wound or neurologic complications. Carotid duplex ultrasonography is performed after 6 months and annually thereafter.
Carotid Angioplasty and Stenting
Carotid angioplasty and stenting (CAS) has emerged as a viable option in the treatment of carotid artery stenosis. Rapid growth and technologic advancements have allowed this procedure to become a treatment strategy, particularly in high-risk patients. Most of the trials published to date have shown varying results with CAS. Many are industry-sponsored, and some have different patient populations (eg, symptomatic and asymptomatic patients). Further randomized prospective studies are needed before any conclusion can be made.
Despite advances in CAS, CEA remains the standard of care. Currently, the Centers for Medicare and Medicaid Services (CMS) have approved reimbursement for CAS only in the following patients :
Symptomatic patients with a high-grade stenosis (>70%) who are considered to be at high risk for CEA
Patients who are at high risk for CEA and have asymptomatic carotid stenosis greater than 80%
The following factors are considered to increase the risk of CAS and should be taken into account in procedural planning :
"Soft" lipid-rich plaque identified on noninvasive imaging
Extensive (≥15 mm) disease
Circumferential heavy calcification
Type III aortic arch
Carotid lesion with more than two 90º bends within a short distance of the target lesion
Significant tortuosity of the distal internal carotid artery
Severe aortic arch atherosclerosis
In a study aimed at identifying angiographic features that would account for the difference in periprocedural stroke and death rates between CAS and CEA, the higher stroke and death rate in patients who underwent CAS was found to be associated with a longer lesion length (≥12.85 mm), sequential lesions, or remote lesions extending beyond the bulb.
The procedure is performed either in an operating room with C-arm capabilities or in an angiographic suite. Local anesthesia with limited sedation is used so that the patient’s neurologic status can be constantly monitored.
Femoral artery access is achieved and an arch arteriogram performed. The affected side is cannulated, and selective carotid arteriograms are then performed (see the images below).
Next, a long sheath is placed over a wire into the common carotid artery, and a 0.014-in. filter wire is placed into the internal carotid distal to the lesion to provide embolic protection. After appropriate sizing, the lesion is quickly predilated with a small balloon. The stent is then placed and postdilated with a larger balloon. (See the images below.)
Next, a completion arteriogram is performed to confirm that the lesion has been treated and that no other abnormalities exist within the internal carotid or cerebral views (see the image below). The procedure is completed, and the access site in the femoral artery is typically closed with a closure device. The patient is usually monitored overnight and discharged the next day.
Cranial nerve injuries occur in 2-7% of patients. Recurrent laryngeal and hypoglossal nerve dysfunctions are the most common. Postoperative stroke occurs in 1-5% of patients. The perioperative mortality is 0.5-1.8%. Recurrent stenosis occurs in 1-20% of cases, and reoperation is necessary in 1-3% of cases.
In the CREST data, the rate of restenosis or occlusion at 2 years was approximately 6%, and there was no difference between CAS and CEA. Secondary analysis of the CREST data sought to identify predictors of restenosis or occlusion. Female sex, diabetes and dyslipidemia were independent predictors of restenosis or occlusion at 2 years after either CEA or CAS. Smoking was also found to be an independent predictor; however, this was only noted in patients who had undergone CEA.
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