The purpose of this study is to compare the safety and performance of WIRION™ EPD in patients undergoing carotid artery stenting to a performance goal based on an analysis of the results of previous US IDE carotid stenting with embolic protection studies

Patient registry procedures include:

• Clinical Events Committee (CEC); responsibility for validating all reported primary safety outcomes
• Data Safety Monitoring Board (DSMB); to review and evaluate safety data including serious adverse events
• 100% data monitoring; to compare data entered into the registry
• Source data verification; to assess the accuracy, completeness of registry data by comparing the data to external data sources (e.g., medical records, paper or electronic case report forms).
• Standard Operating Procedures; to address registry operations and analysis activities, such as patient recruitment, data collection, data management, data analysis and reporting for adverse events.
• Sample size assessment to specify the number of participants and follow up duration.
• Data Management Plan; to address situations where variables are reported as missing, unavailable, "non-reported," uninterpretable, or considered missing because of data inconsistency or out-of-range results
• Statistical analysis plan; describing the analytical principles and statistical techniques to be employed in order to address the primary and secondary objectives, as specified in the study protocol or plan.

Inclusion Criteria:

• 18 years of age
• Anticipated patient life expectancy of at least 1 year
• Patient or authorized representative, signed a written Informed Consent form
• Patient is willing to comply with the protocol requirements
• Candidate for catheter-based therapy of a single stenosis located in the internal carotid artery (ICA) or the carotid bifurcation, suitable for treatment with a single FDA-approved stent with a carotid use indication
• Reference vessel diameter for intended filter location between 3.5mm and 6.0mm
• An adequate "landing zone" of at least 30mm
• Patients with severe symptomatic or asymptomatic carotid artery stenosis, to be ≥ 50% for symptomatic patients OR ≥ 80% for asymptomatic patients
• At least one high surgical risk criteria, either anatomical or co-morbid risk factors, as listed below:

Category I - Anatomical high risk factors

• Recurrent stenosis after endarterectomy
• Previous radical neck surgery or radiation therapy to the neck
• High cervical ICA lesions or CCA lesions at or above C2 or below the clavicle
• Spinal immobility of the neck
• Tracheostomy or tracheal stoma
• Any laryngeal nerve palsy and bilateral carotid artery stenosis

Category II - Co-morbid risk factors

• Contralateral carotid occlusion
• Unstable angina (Canadian Cardiovascular Society class III/IV)
• Congestive Heart Failure (New York Heart Association functional class III/IV) and/or known severe left ventricular dysfunction LVEF<30%
• Requires coronary artery bypass surgery, cardiac valve surgery, major vascular surgery, or abdominal aortic aneurysm repair 31-60 days post carotid stent procedure
• Recent MI (>72 hr and <4 weeks)
• Severe pulmonary disease with FEV1 of <30%
• CAD in ≥2 unrevascularized vessels with stenosis ≥70%
• Age ≥75 years
• Uncontrolled diabetes - Female patient with no child bearing potential or has negative pregnancy test within the previous 7 days and agrees to remain on birth control throughout the study

Exclusion Criteria:

• Total occlusion or near-occlusion of the target vessel
• Severe lesion calcification
• Presence of an alternate source of emboli
• Presence of a filling defect, or angiographically visible thrombus, at target site
• A greater than 50% CCA lesion proximal to the target or a distal (intracranial) lesion more severe than the target lesion
• Evolving, acute or recent stroke within the last 30 days
• Major stroke with a residual neurological deficit that would confound neurologic assessment
• Vertebrobasilar insufficiency symptoms only
• Major operation 30 days before or after the index procedure
• Ipsilateral intracranial stenosis that requires treatment
• Any pre-existing stent in ipsilateral carotid artery, or placement of a stent in contralateral carotid within 30 days of the index procedure
• History of intracranial hemorrhage within 12 months
• Any condition that precludes proper angiographic assessment or prevents femoral arterial access
• Uncontrolled hypertension
• Contraindication to heparin and bivalirudin, aspirin, thienopyridines
• Known sensitivity to radiographic contrast media which cannot be controlled with pre-medication
• History or current indication of bleeding diathesis or coagulopathy
• Chronic renal insufficiency
• Carotid artery dissection or aortic arch anatomical anomalies
• Dementia or a neurological illness
• Patient is enrolled in another drug or device study protocol that has not reached its primary endpoint
• Severe pulmonary hypertension
• Intra-cranial pathology (e.g., tumor, AVM. aneurysm, etc) that would make study participation inappropriate or confound neurologic assessment