• If the efficacy of CAS differs from CEA in preventing stroke, myocardial infarction & death during a 30-day peri-procedural period, or ipsilateral stroke over the follow-up period in patients with symptomatic/asymptomatic extracranial carotid stenosis. [ Time Frame: 4 years ] [ Designated as safety issue: Yes ]
  Although 4-year follow-up data was used to assess the primary endpoint, the published results were based on a median follow-up period of 2.5 years.
  
  

• To describe differential efficacy of CAS and CEA in male and female participants. [ Time Frame: 4 years ] [ Designated as safety issue: Yes ]
  
• To evaluate differences in measures of health related quality of life and cost effectiveness. [ Time Frame: 1-year ] [ Designated as safety issue: No ]
  

The primary aim of the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) is to contrast the relative effectiveness of carotid artery stenting (CAS) versus carotid endarterectomy (CEA) in preventing stroke, myocardial infarction, and death. Stents are medical devices approved and commonly used for treatment of heart disease. The stent that will be used in this trial is the RX ACCULINK(TM) Carotid Stent System, an elastic-like metal scaffold that is expanded inside a carotid artery to hold the vessel open.

The RX ACCUNET(TM) Embolic Protection System (an umbrella-like device that expands above the narrowed portion of the carotid artery) will be used in conjunction with the RX ACCULINK stent. The RX ACCUNET system is designed to capture embolic material that could break off from the narrowed area in the carotid artery while still allowing blood to flow through the vessel during the procedure. Embolic material could block blood flow to the arteries beyond the narrowing and be harmful to the brain. The RX ACCUNET System is closed and removed after the stent is placed.

CEA involves a neck incision and physical removal of the plaque from the inside of the artery. CAS involves insertion of a catheter or tube into an artery in the groin and then threading the catheter through the arteries of the body to the location of the plaque within the carotid artery in the neck. The stent is then placed to cover the plaque and hold the artery open. Participants will be randomly assigned to undergo either CAS or CEA, and all patients will receive best medical management, which includes treatment with aspirin, treatment of high blood pressure, and treatment of other stroke risk factors. Participants will be followed for up to ten years.