Usefulness of the Carotid Ultrasonography to Predict the Severity of Coronary Artery Stenosis

ABSTRACT

BACKGROUND: High-resolution carotid ultrasonography is considered a fundamental technique for the investigation of the vascular system. However, it is still very unclear whether ultrasonographic studies of carotid arteries are useful for the prediction of cardiovascular events in patients with coronary heart disease. We have tried to assess the usefulness of carotid ultrasonography to predict the severity of coronary artery stenosis in the patients with ischemic heart disease. METHODS: We studied in 80 patients(53 men, 27 women) with acute chest pain, mean ages 63.1 10.8 yr(35 to 84 yrs), who underwent both coronary angiography and carotid ultrasonography with 10 MHz transducer. The patients who had received revascularization procedure were excluded. We classified the patients into two groups, the control group without significant coronary stenosis(23 patients) and the coronary artery disease(CAD) group(57 patients) with significant stenosis(>50%). The intima-media thickness (IMT) was measured in the far wall of CCA at 10 mm proximal to carotid bulb and the abnormal IMT was defined when the measurement was greater than mean IMT+2 SD of control group(>0.99 mm). Serum total cholesterolQlC), low density lipoprotein(LDL), high density lipoprotein(HDL), triglyceride(TG) and lipoprotein (a) (LP(a)) were measured and history of hypertension, diabetes mellitus, and smoking were investigated. RESULTS: A significant difference in IMT of the CCA was found between control and CAD group(0.75+/-0.12mm vs. 1.02+/-0.34 mm; p<0.001). Also a significant difference in the existence of plaque(control; 26.1% vs. CAD; 73.7%, p<0.00l) and the number of plaque(control; 0.39+/-0.94 vs. CAD; 2.20+/-1.87 p<0.001) was found. The existence and number of carotid plaque were more conelated with coronary artery stenosis severity than carotid IMT. The sensitivity of IMT for prediction of significant CAD was 42.1%, the specificity 95.7%, the positive predictive value 96%, and the negative predictive value 40%. The sensitivity of plaque presence on the carotid artery for prediction of CAD was 73.7%, the specificity 73.9%, the positive predictive value 87.5% and the negative predictive value 53.1%. Among the risk factors, age and LP(a) were correlated with IMT of CCA, and diabetes, hypertension, age were correlated with the presence of plaque. Smoking and hypertension were correlated with coronary artery disease. CONCLUSION: Carotid atherosclerosis was significantly correlated with severity of coronary atherosclerosis. We therefore suggest that carotid ultrasonography is useful to predict the severity of coronary artery stenosis and that the best index of coronary artery stenosis severity may be carotid plaque rather than carotid intima-media thickness.