Relationship of the intima-media-thickness (IMT) and plaques of the carotid arteries and the arteries of the lower limbs to manifest macrovascular diseases: The RIAD study

The early detection of atherosclerotic arterial lesions is of special impor tance for primary health care. The measurement of the intima-media-thicknes s (IMT) is an accepted method for the evaluation of early atherosclerosis. So far, there is a lack of systematic examinations of IMT and plaques of th e carotids and the arteries of the lower extremity in relation to macroangi opathy in one and the same population. Therefore, we analysed the relations hip of IMT and plaques of the common carotid artery and the arteries of the lower extremity to manifest macrovascular disease. A total of 597 subjects, aged 40 to 70 years, were examined from the RIAD ( Risk factors in IGT for Atherosclerosis and Diabetes) study, who were at ri sk for the development of type 2 diabetes. The participants were interviewe d by standard questionnaires about the history of myocardial infarction, st able or unstable angina pectoris, as well as about history of stroke and pe ripheral arterial occlusion disease. The IMT and atherosclerotic plaques we re examined by B-mode sonography. The subjects with manifest coronary heart disease (CHD) showed significantl y increased IMT of all examined vessels, except for the popliteal artery, a s well as significantly more common plaques of the carotids and the arterie s of the lower extremity in comparison to the subjects without CHD. After a ge and sex adjustment only the difference for carotid plaques remained sign ificant. All IMT measurements, except for the one of the popliteal artery, and the plaques of the carotids and the arteries of the lower extremity wer e significantly correlated to the subjects history for CHD. After adjustmen t for age and sex a significant correlation was found only between carotid plaques and manifest CHD. Obviously, the IM-thickening as an early form of atherosclerosis is not yet inevitably associated with symptomatic CHD. The IMT and plaques of the examined vessels did not correlate with the history of stroke. A significant correlation was found between the plaques of the a rteries of the lower extremity and the IMT of the popliteal artery to manif est peripheral arterial occlusion disease, which was confirmed after age an d sex adjustment. Interestingly, in this population with a rate of 12.7 % of manifest CHD, 1 % of stroke and 1.9 % of peripheral arterial occlusion disease the majority of the subjects (51 %) had asymptomatic atherosclerosis, detected by ultra sound. Since non-stenotic atherosclerosis contributes to most of the cardio vascular events, B-mode ultrasound, especially of the carotids, could be re commended as a valuable screening method for the early detection of asympto matic atherosclerosis.