Background: Carotid and brachial artery intima-media thicknesses (IMT) determined using B-mode ultrasonography are validated surrogate markers of the severity and extent of coronary artery disease (CAD). The markers may also reflect the general vascular atherosclerotic involvement and cardiovascular risk in patients with normal coronary arteries (NCA). We aimed to investigate the relationship of carotid artery IMT (CIMT) and brachial artery IMT (BIMT) with CAD simultaneously, and also examined whether both markers represent cardiovascular risk determined by cardiovascular risk factors in patients with NCA.
Methods: One hundred eligible patients who consecutively underwent coronary angiography under suspicion of CAD were included in this study. The patients were evaluated in terms of age, gender, and the risk factors for CAD, and their total cardiovascular risk was calculated. CIMT and BIMT measurements were performed by B-mode ultrasonography on all patients. The extent and severity of CAD were evaluated by the Gensini score, and the number of severely narrowed vessels was determined by coronary angiography.
Results: Sixty-three patients (47 males, 16 females) with a mean age of 62 ± 10 years had CAD, and 37 patients (20 males, 17 females) with a mean age of 51 ± 11 years had NCA on coronary angiography. The mean age and male ratio of patients with CAD were significantly higher as compared with the patients with NCA (p < 0.001, p = 0.035, respectively). The mean number of diseased vessels was 2.2 ± 0.9 (median 2.0), while the mean Gensini score was 25 ± 31 (median 14.0). The CIMT and BIMT were higher in patients with CAD than in those with NCA (0.9 ± 0.2 vs. 0.7 ± 0.2 mm and 0.5 ± 0.1 vs. 0.4 ± 0.1 mm, respectively; p < 0.001 for both). The cardiovascular risk score (CVRS) was also significantly higher in the CAD group (3.8 ± 1.1 vs. 2.9 ± 1.4, p < 0.001). CIMT, BIMT, and CVRS were significantly correlated with the Gensini score and number of diseased vessels. For the sensitivity and the specificity of CIMT, BIMT, and CVRS to detect the presence of CAD, the areas under the ROC curve were 0.785 (95% CI 0.687-0.883, p = 0.000), 0.842 (95% CI 0.764-0.920, p = 0.000), and 0.721 (95% CI 0.591-0.813, p = 0.001), respectively. When we compared the CVRSs between the groups, which were determined according to cutoff values for CIMT and BIMT (CIMT ≥0.9 vs. <0.9 and BIMT ≥0.4 vs. <0.4); among the patients with NCA, CVRSs were significantly different (3.5 ± 0.5 vs. 2.7 ± 1.4, p = 0.035 and 3.7 ± 1.1 and 2.7 ± 1.3, p = 0.073; respectively).
Conclusion: The increases in both brachial and carotid IMT are positively correlated with the extent of CAD and the number of involved vessels, and have more predictive value for CAD than the traditional CVRS. In addition, carotid IMT is also related to high CVRS in patients with NCA, and this finding may represent general vascular involvement without coronary lesions determined by coronary angiography.
Keywords: Brachial IMT; Cardiovascular risk; Carotid IMT; Coronary angiography; Coronary artery disease; Normal coronary arteries.