Carotid intima-media thickness by B-mode ultrasound as a new tool to recognize cad in patients with no evicences of angiographic narrowings

Objective: to evaluate the ability of external carotid ultrasound (ECU) and quantitative coronary angiography (QCA) to classify patients with coronary atherosclerosis documented by intravascular ultrasound (IVUS). Methods: ECU, IVUS and QCA were performed in 48 patients. The potential of ECU and QCA variables to identify patients with a positive IVUS test (IVUS(+)) was analyzed. Results: The whole group was stratified according to a QCA diagnosis of normality [maximal %-coronary stenosis (%CSmax) =70%; n=13, group C). The lowest group C IVUS-determined coronary-IMTmax was used as threshold to define subjects in group A and B as IVUS(+) or IVUS(-). Five (31.2%) subjects of group A and 16 (84.2%) of Group B were classifiable as IVUS(+) despite their QCA diagnosis of normal or intermediate atherosclerosis. Pooling data from groups A and B, the area under the ROC curve increased from 0.730 to 0.798 to 0.885 when calculated on the basis of %CSmax, carotid-IMTmax, carotid-IMTmean, respectively. Using a 1 mm cut-off value for carotid-IMTmean, no IVUS false negatives were identified neither in group A nor in Group B, and 2/16 patients in Group A and 2/19 in Group B were classifiable as IVUS false positives. Sensitivity, specificity, positive and negative predictive values were 1, 0.75, 1, 0.57 for Group-A and 1, 0.25, 1, 0.83 for Group-B. Conclusions: ECU variables have a higher capacity than QCA variables in recognizing patients with a positive IVUS test. Funding: Research supported in part by Italian Ministry of Healt