Stroke is diagnosed one half million times each year and consumes a tremendous amount of medical resources, costing over fifteen billion dollars a year. In the early 1990's several well-designed studies clearly demonstrated the advantage of carotid endarterectomy over medical therapy in patients in which the carotid artery is narrowed by 60-70% in selected patients. In certain circumstances, such as a person with severe heart disease or other medical problems that makes carotid endarterectomy risky or if the area of narrowing is high in the neck, angioplasty and/or stenting become an option. The narrowed vessel is first dilated using a small balloon passed through a catheter to the point of stenosis (percutaneous transluminal angioplasty- PTA) and held open with a stent (a small flexible wire mesh brace} not unlike those used in coronary catheterization (percutaneous transluminal stenting- PTS).