Carotid Intima-Media Thickness And Atheromatous Plaque Detected By Ultrasonography Predict Coronary Artery Disease

Objective: The purpose of this investigation is to evaluate the predictive value of carotid intima-media thickness (IMT) and atheromatous plaque detected by two-dimensional ultrasonography for coronary artery disease (CAD).Methods: According to the result of coronary angiography (CAG), seventy six cases were divided into the group with CAD (n=52) and the group without CAD (n=24). Ultrasonography with high resolution was performed in these cases respectively imaging of the common carotid, internal carotid and carotid bifurcation for detection of atheromatous plaque. The measurement of IMT was focused in the image of the far wall of the distal 1.0 cm of the common carotid proximal to the bifurcation where there were not plaques. Using receiver operating characteristic (ROC) curve, we evaluated the value of IMT in diagnosis of CAD. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of IMT and atherosclerosis plaque in diagnosis of CAD were calculated with gold standard of CAG.Results: We found that the IMTs in non-CAD group and CAD group were 0.79±0.11 mm and 1.11 ±0.37 nun, the prevalence rates ofatherosclerosis plaque were 8.3% (2/24) and 71.2% (37/52) respectively. There were significant differences between the two groups (P<0.001). The Area Under ROC Curve (AUC) was 0.800, with its 95% confidence interval (0.699-0.900) proved to P<0.01 by Z test (Z=5.8412) and lower limit 0.699 far from 0.5. At peak point of the ROC curve the cut-off value for IMT was 0.9 mm with a sensitivity of 75%, a specificity of 87.5% and an accuracy of 78.9%. An IMT≥0.9 mm of the common carotid artery and / or the occurrence of atherosclerosis plaque could predict the presence of CAD with a sensitivity of 82.7%, a specificity of 79.2%, a positive predictive value of 89.6% and an accuracy of 85.5%. Conclusions: Two-dimensional ultrasonography with high resolution has such outstanding features as convenience, noninvasion, good repetition and so on. The IMT of CCA has the definite veracity in diagnosis of CAD. An IMT≥0.9 mm as the diagnostic critical value of CAD was proved to be better in sensitivity and specificity. The detection of IMT and plaque in the carotid artery is a sensitive predictor of CAD.