Background-We tested prospectively the hypothesis that stroke development can be predicted by echolucency of carotid atherosclerotic plaques in previously symptomatic and asymptomatic patients. Methods and Results-We followed incidence of ipsilateral ischemic strokes for 4.4 years in 111 asymptomatic and 135 symptomatic patients with Ն50% relevant carotid artery stenosis. At inclusion, echogenicity of carotid plaques and degree of stenosis were evaluated with high-resolution B-mode ultrasound with computer-assisted image processing and Doppler ultrasound, respectively. We observed 44 ipsilateral ischemic strokes. In symptomatic patients, relative risk of ipsilateral ischemic stroke for echolucent versus echorich plaques was 3.1 (95% CI, 1.3 to 7.3), whereas for 80% to 99% versus 50% to 79% stenosis, the relative risk was 1.4 (95% CI, 0.7 to 3.0). Relative to symptomatic patients with echorich 50% to 79% stenotic plaques, those with echorich 80% to 99% stenotic plaques, echolucent 50% to 79% stenotic plaques, and echolucent 80% to 99% stenotic plaques had relative risks of ipsilateral ischemic strokes of 3.1 (95%CI, 0.7 to 14), 4.2 (95% CI, 1.2 to 15), and 7.9 (95% CI, 2.1 to 30), equivalent to absolute risk increases of 11%, 18%, and 28%. This was not observed in previously asymptomatic patients. Conclusions-Echolucent

Background-Echo-lucency of carotid atherosclerotic plaques on computerized ultrasound B-mode images has been associated with a high incidence of brain infarcts as evaluated on CT scans. We tested the hypotheses that triglyceride-rich lipoproteins in the fasting and postprandial state predict carotid plaque echo-lucency and that echo-lucency predicts a high plaque lipid content. Methods and Results-The study included 137 patients with neurological symptoms and Ն50% stenosis of the relevant carotid artery. High-resolution B-mode ultrasound images of carotid plaques were computer processed to yield a measure of echogenicity (gray-scale level). Lipoproteins were measured before and hourly for 4 hours after a standardized fatty meal. A subgroup of 58 patients underwent endarterectomy. On linear regression analysis, echo-lucency (low gray-scale level) was associated with elevated levels of fasting and postprandial plasma triglycerides (Pϭ.0002 and Pϭ.002) [5][6][7] and stroke, 5,7 and even reduced total mortality. 5,6 The role of triglyceride-rich lipoproteins is much less clear. Nevertheless, elevated plasma triglyceride levels have repeatedly been associated with an increased incidence of myocardial infarction, 8 and three intervention trials have provided some evidence that a reduction in triglyceride-rich lipoproteins is associated with a reduction in the progression of coronary atherosclerosis 9 and the incidence of coronary events. -11In a recent study, we demonstrated that elevated plasma levels of triglyceride-rich lipoproteins in the fasting or postprandial state were associated with echo-lucent carotid artery plaques as evaluated subjectively by B-mode ultrasonography. 12Weak reflection of ultrasound from carotid atherosclerotic plaques, ie, echo-lucency, is also associated with a higher histological content of lipids, 13 as well as with increased risk of developing neurological symptoms.14 -17 It is therefore conceivable that elevated plasma levels of triglyceride-rich lipoproteins may be associated with atherosclerotic plaques, with lipid-rich cores particularly prone to rupture and causing neurological symptoms, and that such plaques can be diagnosed noninvasively and subjectively as echo-lucent plaques on B-mode ultrasonography.Recently, computerized assessment of plaque echogenicity (measured as gray-scale level) has been introduced as a more quantitative and objective method of ultrasonographic plaque characterization. 18 -20 With this improved method, a high fibrous tissue content was associated with a high gray-scale value (echo-rich plaque), whereas a high lipid and hemorrhage content was associated with a low gray scale value (echo-lucent plaque). 20 In addition, plaque echo-lucency was associated with a higher incidence of brain infarcts as assessed with CT scans. 18,19 In this study, we tested the hypotheses that (1) elevated plasma levels of triglyceride-rich lipoproteins in the fasting or postprandial state predict echo-lucency of carotid atherosclerotic plaques on computerized ultrasound B-...