Clinical Significance of B-Mode Ultrasound of Common Carotid Artery for Prediction of Severity of Coronary Artery Disease: Important Parameters on Hand Measurement

ABSTRACT

BACKGROUND AND OBJECTIVES: As a predictor of atherosclerosis, the intima-media thickness (IMT) of the common carotid artery (CCA) shows only a weak correlation with the extent of coronary artery disease (CAD). The purpose of this study was to evaluate the hand measured IMT value of the CCA as reliable and strong predictors of the severity of coronary artery atherosclerosis. SUBJECTS AND METHODS: We performed an ultrasonographic examination of the right CCA by using a 15 MHz linear array transducer in 268 patients (M F=160 108, mean age 61.2+/-10.2) who underwent coronary angiography to evaluate ischemic heart disease. The internal dimension, maximal IMT, irrespective of location and morphology (focal or diffuse), and the IMT of 6 more randomly selected points in the CCA were measured. We classified the plaques as type A (low or equal echo density compared with adventitia) or type B (higher echo density than adventitia). Modified Gensini scores were calculated, as a marker of the extent of CAD, and compared with the results of the IMT examination. RESULTS: Carotid plaques were detected in 156/268 (58%) patients. 119 and 37 patients were types A and B, respectively. The Gensini score was significantly higher in patients with type B (40.6+/-23.5) than type A plaques (29.3+/-21.7) (p=0.01). Modified Gensini score was correlated with age (r=0.22 p<0.001), mean IMT (r=0.178, p=0.004) and maximal IMT (r=0.296, p<0.001). After adjusting for age, the maximal IMT was the sole independent variable reflecting the severity of CAD (p=0.001). CONCLUSION: The maximal IMT, together with the type of CCA plaque morphology, provides more reliable information about the severity of CAD than the conventional mean IMT.