Adapt Monorail Carotid Stent System: A Postmarket Clinical Follow-up Study

Inclusion Criteria: * High-risk for carotid endarterectomy due to anatomical or co-morbid conditions and either has neurological symptoms and ≥ 50% stenosis, via angiography or is asymptomatic and has ≥ 80% stenosis, via angiography * Target lesion located in the common carotid artery (CCA), internal carotid artery (ICA), or carotid bifurcation * Arterial segment to be stented has a diameter between 4mm and 9mm * Age ≥ 18 years * Life expectancy \> 12 months from the date of the index procedure Exclusion Criteria: * Contraindication to percutaneous transluminal angioplasty (PTA) * Severe vascular tortuosity or anatomy that would preclude the safe introduction of a guide catheter, sheath, embolic protection system or stent system * Lesions in the ostium of the common carotid artery * Occlusion of the target vessel * Evidence of intraluminal thrombus * Known sensitivity to nickel-titanium * Known allergy to heparin, aspirin or other anticoagulant/ antiplatelet therapies, or is unable or unwilling to tolerate such therapies * Uncorrectable bleeding disorders, or will refuse blood transfusions * History of prior life-threatening contrast media reaction * Previous stent placement in the target vessel * Evolving stroke or intracranial hemorrhage * Previous intracranial hemorrhage or brain surgery within the past 12 months * Clinical condition that makes endovascular therapy impossible or hazardous