INTRODUCTION Atherosclerotic renal artery stenosis (RAS) is an increasingly recognized clinical entity, and is especially common among patients with atherosclerotic disease in other vascular beds. Ultrasound screening of an unselected Medicare population demonstrated a prevalence rate of 6.8% in RAS >60%.1 In patients suspected of coronary artery disease (CAD) undergoing cardiac catheterization, RAS has been found in 15% to 30%.2-7 Among patients with atherosclerotic disease of the lower extremities, the prevalence of RAS is estimated at greater than 30%.8-10

NATURAL HISTORY The natural history of RAS is one of progressive diseases, resulting in functional loss and total occlusion. In a trial randomizing patients with significant RAS (>50%) to medical therapy or balloon angioplasty, progression to total occlusion over a 1-year period occurred in 16% of those treated with medical therapy as compared with none among those treated with angioplasty.11

A second study demonstrated that progression to total occlusion occurred more commonly as the severity of stenosis increased.12