Carotid intima thickness assessed using high-resolution ultrasound as a structural correlate of endothelial dysfunction

Purpose This study evaluated the association between carotid intima thickness (cIT), measured using high-resolution ultrasound, and endothelial cell dysfunction (ECD), assessed using flow-mediated dilation (FMD), for early atherosclerosis risk assessment. Methods Between January and December 2024, 102 middle-aged nonsmoking participants were prospectively recruited; 66 were included in the final analysis and classified into a risk group (n=44) or control group (n=22) according to the presence or absence of at least one conventional cardiovascular risk factor. Data collected included demographic characteristics, physical measurements, laboratory findings, cIT, carotid media thickness (cMT), and carotid intima-media thickness (cIMT). After 5 minutes of forearm occlusion, brachial artery diameters were measured at baseline and at 30, 60, and 120 seconds after cuff deflation during systole and diastole, and FMD indices were calculated. Receiver operating characteristic (ROC) curve analysis was performed, with differences between the ROC curves evaluated using the Hanley-McNeil test. Results Compared with the control group, the risk group had greater cIT (P<0.001) and cIMT (P=0.016) and generally lower FMD indices. cMT did not differ significantly between groups (P=0.595). Among carotid ultrasound parameters, cIT showed the strongest association with atherosclerosis risk (standardized β=0.489, P<0.05) and the strongest inverse correlation with systolic FMD measured 60 seconds after cuff deflation (FMD S60 ; ρ=−0.689, adjusted P=0.001). In ROC analysis, cIT generally showed better performance for identifying ECD than cMT and cIMT, with a maximum area under the curve of 0.896 (P<0.001). Conclusions High-resolution ultrasound measurement of cIT may provide a noninvasive imaging marker of early endothelial dysfunction.