Abstract 3118: Combined Assessment of Intima-Media Thickness and Echolucency of an Atherosclerotic Plaque in Carotid Artery has an Additive Value on Prediction of Future Coronary Events in Patients with Coronary Artery Disease and Carotid Atherosclerosis
Single ultrasound assessment of either intima-media thickness (IMT) or plaque echolucency of carotid artery is considered a surrogate for systemic atherosclerotic burden and provides prognostic information for coronary events. The assessment of IMT and plaque echolucency of carotid artery has the advantage of obtaining structural and compositional information on atherosclerotic plaques in a single session. This study examined the hypothesis that the combined ultrasound assessment of IMT and echolucency in a carotid artery may have an additive effect on the prediction of coronary events in patients with coronary artery disease (CAD). Ultrasound assessment of carotid IMT and plaque echolucency with integrated backscatter (IBS) analysis (intima-media IBS value minus adventitia IBS) was performed in 411 patients with CAD and carotid plaques (IMT ≥ 1.1 mm). The plaque with the greatest axial thickness in carotid arteries was the target for measurement of maximum IMT (plaque-IMTmax) and echolucency (lower IBS reflects echolucent plaque). All patients were prospectively followed up for 70 months or until the occurrence of one of the following coronary events: cardiac death, nonfatal myocardial infarction, or unstable angina pectoris requiring revascularization. During follow-up, 49 coronary events occurred (cardiac death in 2, myocardial infarction in 10, unstable angina in 37). In a multivariate Cox hazards analysis, plaque-IMTmax and plaque echolucency (lower IBS value) were significant predictors of coronary events (HR; 1.82 and 0.85, 95% CI 1.2 – 2.9 and 0.80 – 0.91, respectively, both p < 0.01) independently of age, LDL-C levels, and diabetes. When outcomes were stratified according to plaque-IMTmax and plaque echolucency in combination or alone, the combination of plaque-IMTmax and plaque echolucency was the strongest predictor of events, followed by plaque echolucency and plaque-IMTmax, on the basis of the c-statistic (area under the ROC curve; 0.80, 0.73, and 0.71, respectively). Combined ultrasound assessment of IMT and echolucency of carotid plaque had an additive value on the prediction of coronary events, and these simultaneous ultrasound measurements may be useful for risk stratification in CAD.