Endarteriectomy may be of some benefit for those patients who have asymptomatic carotid stenosis above 80%. Duplex echography is a useful non-invasive diagnosis method, and the detection of asymptomatic carotid stenosis is questionable. Detection in the whole population seems inefficient since most stenosis are found in patients who experience other locations of atherosclerosis or who have several risk factors. The conditions where detection seems useful are the patients above 55 years with lower limb occlusive arterial disease or aortic aneurysm, and the subjects who have three of the four following conditions: age above 65 years, hypercholesterolemia, tobacco, and ischaemic cardiopathy.