Proximal Protection With The Mo.Ma Device During Carotid Stenting

General inclusion criteria Subject meets one or more of the high surgical risk criteria. * Subject is ≥ 18 years old. * Subject is a candidate for single lesion carotid artery stenting using a femoral arterial approach. * Subject is willing and able to comply with follow-up evaluations at the specified times. * Subject (or legal representative) understands the nature of the procedure and provides informed consent, prior to enrollment in the study. * If female subject, is not currently pregnant and has stated that she has no intention of becoming pregnant during the study. Angiographic inclusion criteria (as determined ≤ 30 days prior to procedure): * Target lesion stenosis (% stenosis = (1-N/D) X 100)1, documented by selective angiography pre-intervention, is * ≥ 80% stenosis for asymptomatic subjects or * ≥ 50% stenosis for symptomatic subjects. Symptomatic is defined as carotid stenosis associated with ipsilateral transient or visual TIA evidenced byamaurosis fugax, ipsilateral hemispheric TIAs or ipsilateral ischemic stroke within 6 months prior to enrollment. * Target lesion is within the internal carotid artery and/or involves the bifurcation of the CCA. * External carotid artery diameter where the Mo.Ma device will be positioned is 3-6 mm. * Common carotid artery diameter where the Mo.Ma device will be positioned is 5-13 mm. General exclusion criteria * Subject has participated in, is participating in, or plans to participate in another clinical study that may affect either the pre-procedure or follow-up results. * Subject has chronic or paroxysmal atrial fibrillation that is not treated by Coumadin. * Subject has undergone prior stenting of the ipsilateral carotid artery. * Subject's life expectancy is less than twelve months. * Subject is unable to respond to external questions and stimuli and to exert a pressure with the contralateral hand. * Subject is suffering from dementia. * Subject has documented intolerance to BOTH heparin and Angiomax. * Subject has an allergy or contraindication to acetylsalicylic acid (ASA). * Subject has a documented allergy to the device materials. * Subject has a documented allergy to radiographic contrast that cannot be pre-treated. * Subject has a documented allergy or contraindication to BOTH clopidogrel and ticlopidine. * Subject has had active bleeding diathesis requiring blood transfusion within one (1) month prior to index procedure. * Subject has had an MI within 72 hours prior to carotid stenting. * Subject has had coronary artery bypass graft (CABG) or vascular surgery within 30 days PRIOR TO index procedure (percutaneous coronary intervention is permissible provided cardiac enzymes are normal within 24 hours of index procedure), OR has planned CABG, vascular surgery, percutaneous coronary intervention (PCI), or has other invasive medical procedures planned within 30 days AFTER index procedure.(Unplanned urgent or emergent procedures may be performed at anytime as clinically indicated). * Subject has a major residual neurological deficit (stroke scales: Barthel ≤ 60, NIH ≥ 15 or Rankin \> 3) at pre-procedure neurological exam. * Subject has had a transient ischemic attack (TIA) or amaurosis fugax within 48 hours prior to index procedure. * Subject has had a stroke or retinal artery occlusion within one (1) month prior to index procedure. * Subject had abnormal pre-intervention blood counts with platelets \< 50,000/cubic mm or \> 700,000/cubic mm or white blood cell count \< 3,000/cubic mm. * Subject has severe chronic renal failure (creatinine \> 2.5 mg/dl). * Subject is currently being treated for cerebral carcinoma or sarcoma. * Subject has peripheral vascular disease, which precludes safe femoral artery sheath insertion. * Subject is unable or unwilling to undergo insertion of a temporary pacemaker. Angiographic exclusion criteria (as determined ≤ 30 days prior to procedure): * The target carotid artery is completely occluded. * The common carotid artery ostium has stenosis that requires treatment. * Multiple carotid stenoses exist in the internal carotid artery (ICA) that cannot be covered by one stent. * The presence of ipsilateral intracranial stenosis that requires treatment. * The presence of any intracranial tumor(s), arteriovenous malformation(s) (AVMs), or aneurysm(s) requiring treatment. * The inability to position a stiff .035" guidewire in the external carotid artery (ECA). * Contralateral occlusion of internal carotid artery and vertebral arteries. * Aortic arch anatomical anomalies that preclude the safe placement of the device.