Abstract-In studies on carotid artery intima-media thickness and stroke, researchers implicitly assume that cerebrovascular abnormalities show a symmetrical distribution. To evaluate whether there is a difference in intima-media thickness between the 2 carotids, we compared left and right common carotid artery intima-media thickness as measured by B-mode ultrasonography in a group of 102 untreated hypertensive patients. This yielded a significant difference between both sides (left, 0.75Ϯ0.11 mm; right, 0.71Ϯ0.11 mm; PϽ0.001). This was associated with a higher cross-sectional area of the intima-media complex and a higher flow velocity at the left side. Arterial diameters, however, were not different. We also assessed whether there is a side preference with respect to cerebrovascular accidents. To this end, we explored our population-based Stroke Registry of 1843 subjects and indeed found a significantly higher incidence of nonlacunar cerebrovascular stroke at the left side, whereas lacunar infarcts were symmetrically distributed. Our findings suggest a predilection for cerebrovascular disease at the left side, which may be related to greater hemodynamic stress and intimal damage in the left carotid artery. Key Words: carotid arteries Ⅲ atherosclerosis Ⅲ cerebral arteries Ⅲ stroke A n increase in carotid artery intima-media thickness (IMT) not only coincides with other risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus but also correlates independently with clinical end points such as myocardial infarction and peripheral atherosclerosis. [1][2][3][4][5][6][7] Recent data have confirmed the relationship between IMT and stroke, especially of the nonlacunar subtype. 8 Thus, an increase in IMT can be considered as a marker of cardiovascular risk. Usually, one averages measurements from the left and right common carotid artery for the determination of IMT. 9 However, it is not known whether this is justified, as differences may exist in IMT between both arteries. Indeed, during routine assessment, we frequently noted a left-right difference in IMT. Other studies also suggest differences between left and right IMT, 5,9 but it is not clear whether there is a systematic increase in favor of one side. This prompted us to systematically compare left and right IMT in a group of hypertensive patients who had been referred to our hospital for evaluation of their elevated blood pressure. Although an increased IMT of the internal carotid artery correlates well with the risk of both myocardial infarction and stroke, a higher IMT of the common carotid artery (CCA) is a good predictor of stroke incidence as well as prevalent stroke. 10,11 Moreover, Cupini and coworkers 8 demonstrated that CCA IMT values are higher in patients with nonlacunar stroke than in those with lacunar stroke, thereby lending further support to the notion that an increased IMT is a marker of atherosclerotic (ie, nonlacunar) cerebrovascular complications rather than of microvascular (lacunar) lesions. For these reasons and because ...
