Abstract 13856: Plaque Echolucency of Carotid Artery is Useful for Assessment of Residual Cardiovascular Risk in Patients with Coronary Artery Disease after Achievement of LDL-C Goals on Statin Therapy
Ultrasound assessment of either intima-media thickness (IMT) or plaque echolucency of carotid artery is a surrogate for systemic atherosclerotic burden and provides prognostic information for coronary events. These parameters of the carotid artery change after lipid-lowering therapy using statin. This study examined hypothesis whether IMT and plaque echolucency of carotid artery may remain useful for prediction of coronary events in patients with coronary artery disease (CAD) after achievement of LDL- C goals (<100mg/dL) by statin.
Methods and Results: Ultrasound assessment of carotid IMT and plaque echolucency with integrated backscatter (IBS) analysis was performed in 202 stable CAD patients with carotid plaques (IMT > 1.1 mm) and LDL-C levels <100mg/dL on statin therapy. 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, 25 coronary events occurred (cardiac death in 3 patients, myocardial infarction in 4, unstable angina in 18). In a multivariate Cox hazards analysis, plaque echolucency (lower IBS value) but not plaque-IMTmax was a significant predictor of coronary events (HR; 0.87 and 1.37, 95% CI 0.79 - 0.97 and 0.70 - 2.69, p = 0.009 and 0.36, respectively) that was dependent of the Framingham risks (age, TC, HDL, systolic BP, smoking and diabetes mellitus). Moreover, addition of plaque echolucency to the Framingham risks improved net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI; 0.26, p < 0.05, and IDI; 0.06, p < 0.01), while addition of plaque-IMTmax did not (NRI; -0.03, p = 0.63, and IDI; 0.01, p= 0.57).
Conclusions: Plaque echolucency but not plaque-IMTmax of the carotid artery had a predictive value and increased the predictability of coronary events in CAD patients with LDL-C < 100 mg/dL on statin treatment. Echolucency of carotid plaque remains useful for assessment of the residual cardiovascular risks in CAD patients.
- © 2012 by American Heart Association, Inc.