Effects of Carotid Stent Design on Cerebral Embolization

• Composite of any stroke, myocardial infarction or death [ Time Frame: within 30 days after the carotid stenting procedure ] [ Designated as safety issue: No ]
• Subclinical cerebral embolization assessed by brain diffusion-weighted MRI [ Time Frame: within 24 hours after carotid artery stenting ] [ Designated as safety issue: No ]

• Composite of any stroke, myocardial infarction or death [ Time Frame: within 30 days after the carotid stenting procedure ] [ Designated as safety issue: No ]
• Subclinical cerebral embolization [ Time Frame: within 24 hours after carotid artery stenting ] [ Designated as safety issue: No ]

The goal of the proposed study is to contrast the relative efficacy of closed-cell stents versus open-cell stents in preventing periprocedural cerebral embolization in high-risk patients with symptomatic and asymptomatic extracranial carotid stenosis undergoing carotid artery stenting (CAS).

Stroke is responsible for more than 10% of all deaths and much severe disability in developed countries. In the United States, approximately 600,000 new strokes are reported annually, of which 150,000 are fatal, and more than 4,000,000 surviving stroke victims are affected by significant disability. Seventy-five percent of strokes occur in the distribution of the carotid arteries and are considered of a thromboembolic etiology, most of which originate in carotid lesions. Carotid artery stenting (CAS) with cerebral embolic protection is currently the preferred treatment of carotid stenosis in high risk surgical patients, i.e., those with significant comorbidities or a hostile neck from previous surgical procedures or radiation. Although several predictors of adverse outcomes after CAS have been identified, the effects of device characteristics, including stent design, on neurologic adverse events have not been established.

The proposed study will be a randomized prospective controlled trial designed to test the hypothesis that the implantation of closed-cell stents for carotid lesions in high-risk patients will be associated with a reduced perioperative cerebral microembolization, as detected by transcranial Doppler and diffusion-weighted magnetic resonance imaging of the brain, and reduced 30-day stroke, myocardial infarction, and death rates when compared with the implantation of open-cell stents.

• Stroke
• Carotid Stenosis

• Device: closed-cell stent
  Closed-cell stent: Comparison of two types of carotid stent designs (open- vs. closed-cell) regarding the primary and secondary outcomes.
  Other Name: Carotid artery angioplasty
• Device: Open-cell stent
  Open-cell Stent: Comparison of two types of carotid stent designs (open- vs. closed-cell) regarding the primary and secondary outcomes.
  Other Name: Carotid artery angioplasty

• Active Comparator: Closed-cell stent
  Intervention: Device: closed-cell stent
• Active Comparator: Open-cell stent
  Intervention: Device: Open-cell stent

Inclusion Criteria:

• Subject is at high risk for carotid endarterectomy due to either anatomic or co-morbid conditions; AND
• Symptomatic patients (TIA or non-disabling stroke within 6 months of the procedure), with carotid stenosis ≥ 50% as diagnosed by angiography, using NASCET methodology (50); OR
• Asymptomatic patients with carotid stenosis ≥ 80% as diagnosed by angiography, using NASCET methodology

Exclusion Criteria:

• Conditions that interfere with the evaluation of endpoints
• Subject has anticipated or potential sources of cardiac emboli
• Subject plans to have a major surgical procedure within 30 days after the index procedure.
• Subject has intracranial pathology that makes the subject inappropriate for study participation.
• Subject has a total occlusion of the ipsilateral carotid artery (i.e., CCA).
• Severe circumferential lesion calcification that may restrict the full deployment of the carotid stent.
• Carotid stenosis located distal to the target stenosis that is more severe than the target stenosis.