[Non-invasive method of evaluating atherosclerosis in elderly patients]

Evidence has accumulated that impairment of vascular endothelial function is the initial step in the development of atherosclerosis. One important finding is the impairment of the release of the endothelium-dependent relaxing factor, which is now thought to be nitric oxide or its related substances, from endothelial cells. Flow-mediated dilatation (FMD) induced by reactive hyperemia has been know to be endothelium dependent, and this can be detected during reactive hyperemia by high-resolution ultrasound in superficial arteries. Several coronary risk factors such as hypercholesterolemia, smoking and hyperhomocysteinemia have been reported to be significantly related with decreased FMD. A non-invasive technique using B-mode ultrasonography can visualize and assess the lumen and vessel wall of the carotid artery. We analyzed Intima-media thickness (IMT) of the right common carotid artery using this method. IMT thickening consists of both an intimal atherosclerotic process and medial hypertrophy. Since IMT is increased in subjects with familial hypercholesterolemia and shows a progressive reduction with cholesterol-lowering treatment. IMT seems to be significantly related to the early phase of atherosclerosis. Ankle brachial pressure index and pulse wave velocity have been clinically applied to evaluate atherosclerosis. These methods are also introduced in this symposium.