Atherosclerotic Disease of the Carotid Artery Treatment & Management

• Antiplatelet agents

  • Aspirin (30–1350 mg qd) 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 TIAs, stroke, and death in men was shown in the Canadian Cooperative Study Group.^[2]
  • Ticlopidine (250 mg bid) 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 qd) is similar to ticlopidine; risk of neutropenia is low.
• Anticoagulation: Warfarin (titrated international normalized ratio [INR] 2–3) use in patients with noncardiac emboli is controversial.
• Of the indications listed above (see Indications section), medical management was found to be inferior to carotid endarterectomy.

Endovascular therapy

• 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.
  • Numerous studies, including the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial, have found that CAS is not inferior to carotid endarterectomy (CEA) at one year. Published long-term results show no significant difference between groups in the prespecified secondary endpoint trial, a composite at 3 years of death, stroke, or myocardial infarction (MI) within 30 days of the procedure (or death or ipsilateral stroke between 31 and 1080 days).^[3]
  • The endarterectomy versus stenting in patients with symptomatic severe carotid stenosis (EVA-3S) trial revealed a higher stroke and death rate in CAS; however, cerebral protection was not uniformly used and dual antiplatelet therapy was not initiated on all patients.^[4]
  • Another study evaluated the outcomes of 2502 patients with symptomatic or asymptomatic carotid stenosis after undergoing carotid-artery stenting or carotid endarterectomy. The study found that the risk of stroke, myocardial infarction, or death was similar with both procedures. However, a higher risk of stroke was found with the stenting technique and a higher risk of myocardial infarction was found with the endarterectomy technique.^[5]
  • Most of the trials (see the Reference section) have shown varying results with CAS. Many are industry sponsored and some have different patient populations (ie, symptomatic and asymptomatic patients). Further randomized prospective studies are needed before any conclusion can be made. Despite advances in carotid artery stenting, carotid endarterectomy remains the current standard of care.
  • Currently, the Centers for Medicare and Medicaid Services (CMS) have approved reimbursement for CAS only in symptomatic patients with a high-grade stenosis (>70%) who are deemed high risk for CEA, and those patients who are at high risk for CEA and have asymptomatic carotid stenosis greater than 80%.^[6]
• Procedural details

  • The procedure is performed in either an operating room with C-arm capabilities or an angiographic suite.
  • Local anesthesia with limited sedation is used so that the patient's neurologic status can constantly be monitored.
  • Femoral artery access is achieved and an arch arteriogram performed. The affected side is cannulated and selective carotid arteriograms are then performed. Next, a long sheath is placed over a wire into the common carotid artery and a 0.014 inch filter wire is placed into the internal carotid distal to the lesion to provide for embolic protection. Next, after appropriate sizing, the lesion is predilated quickly with a small balloon. The stent is then placed and postdilated with a larger balloon. A completion arteriogram is than performed to ensure that the lesion has been treated and that no other abnormalities exist within the internal carotid or cerebral views. 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.
• Carotid endarterectomy

  • To evaluate the relative short-term safety and intermediate-term efficacy of carotid endarterectomy versus carotid artery stenting, Meier et al conducted a systematic review and meta-analysis of 11 randomized controlled clinical trials.^[7] Carotid endarterectomy carried a lower risk of periprocedural mortality or stroke than did carotid stenting (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.47-0.95; P=0.025), mainly because of a decreased risk of stroke (0.65, 0.43 to 1.00; P=0.049).
  • However, the risk of death (OR, 1.14; CI, 0.56-2.31; P=0.727) and the composite end point mortality or disabling stroke (OR, 0.74; CI, 0.53-1.05; P=0.088) did not differ significantly between the two procedures. The odds of periprocedural myocardial infarction (OR, 2.69; CI, 1.06-6.79; P=0.036) or cranial nerve injury (OR, 10.2; CI, 4.0-26.1; P< 0.001) were higher with the carotid endarterectomy group than with the carotid stenting group. In the intermediate term, the risk of stroke or death did not differ significantly with the two treatments (hazard ratio, 0.90; 95% CI, 0.74-1.1; P=0.314).
  • Another study suggested that with regard to timing of carotid endarterectomy, previous or simultaneous carotid endarterectomy in patients with unilateral severe asymptomatic carotid stenosis (>70%) undergoing a coronary artery bypass graft can better prevent stroke than delayed carotid endarterectomy. The overall surgical risk was not increased.^[8]

• Cardiac evaluation

  • Patients with carotid artery stenosis have a high incidence of concomitant coronary artery disease.
  • Adherence to the American Heart Association's recommendations regarding cardiac evaluation for noncardiac surgery should be followed. In summary, they recommend a functional assessment 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 ECG may undergo carotid endarterectomy without further cardiac workup.
• Preoperative imaging studies

  • Imaging studies should be used to determine the extent of stenosis and to evaluate for kinks and coils that may affect the conduct of the operation (see Imaging Studies). Many surgeons who work with certified laboratories proceed with surgery based on the carotid duplex alone. If any doubt exists regarding the degree of stenosis or the distal extent of the disease, an arch and carotid arteriogram is performed.
  • The extent of the disease should also be noted, with particular attention to the superior extent of the stenosis. This may impact the type of anesthesia chosen and reveal the need for additional measures to expose an unusually high lesion.

• Anesthesia

  • 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, stump pressures, and transcranial Doppler or some other form of cerebral monitoring to assess the need for a shunt.
• Incision

  • A vertical incision should be made along the anterior border of the sternocleidomastoid muscle.
  • An oblique incision should be made in the skin fold over the carotid bifurcation.
• Endarterectomy

  • 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. Occasionally, tacking sutures are required to accomplish this.
• Shunt (see Anesthesia)
• Closing

  • The endarterectomy is closed either primarily or with a patch.
  • The technical result should be verified by completion angiography or duplex.

• Obtain CBC count and electrolytes, and perform an ECG.
• Perform frequent neurologic assessment.
• Institute hemodynamic monitoring, with focus on maintaining the patient's blood pressure at its preoperative range.
• Observe the patient for a hematoma that may compromise the airway.
• Antiplatelet therapy is necessary.

• Patients are evaluated 2 weeks postoperatively for wound or neurologic complications.
• Carotid duplex is performed after 6 months and then annually.
• For excellent patient education resources, visit eMedicine's Stroke Center and Cholesterol Center. Also, see eMedicine's patient education articles Stroke, High Cholesterol, Understanding Your Cholesterol Level, and Lifestyle Cholesterol Management.

• Cardiac ischemia
• Cranial nerve injury
• Hematoma with or without airway compromise
• Hypertension and hypotension
• Perioperative stroke
• Recurrent stenosis

• 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.^[1]
• The perioperative mortality rate is 0.5-1.8%.
• Recurrent stenosis occurs in 1-20% of cases, and reoperation is necessary in 1-3% of cases.
• Following a successful carotid endarterectomy, the 2-year stroke risk in the NASCET was 1.6%, compared with 12.2% for the medically managed patients.^[1]
• In the NASCET, the cumulative risk of an ipsilateral stroke was 9% for the surgical patients and 26% for the medically managed patients.^[1]
• In the Asymptomatic Carotid Atherosclerosis Study (ACAS), the 5-year risk for ipsilateral stroke was 5.1% for the surgical group compared with 11% for the medical group. The stroke risk of arteriography was attributed to the surgical group and was 1.2%.^[9]
• In the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial, carotid stenting was found to not be inferior to carotid endarterectomy in patients with severe stenosis and coexisting conditions.
• Recent meta-analysis revealed that protected (use of embolic protection wire) carotid angioplasty and stenting was associated with a 30-day stroke and death rate of 2.4%.^[10]

Carotid angioplasty and stenting research will continue to evolve, and studies are underway to evaluate its role in asymptomatic patients with high grade stenosis.

As industry and interest from numerous specialties continues in carotid angioplasty and stenting, the devices available will continue to evolve.