Association Between Cigarette Smoking and Carotid Plaque Stiffness Assessed Using Ultrasound Shear-Wave Elastography

Background: Cigarette smoking alters carotid plaque composition. Two-dimensional ultrasound shear-wave elastography (2D-SWE) is a promising non-invasive imaging technique for quantifying plaque stiffness. This prospective study aimed to determine whether carotid plaque stiffness assessed using 2D-SWE is associated with smoking status. Methods: A total of 132 carotid plaques were evaluated from 93 patients who underwent carotid ultrasound 2D-SWE. Demographic and clinical data were collected, and patients were classified as current cigarette smokers (n = 45) and non-smokers (n = 48). A total of 65 carotid plaques in smokers and 67 in non-smokers were evaluated. Plaque stiffness was quantified using shear-wave velocity (m/s), with three SWE measurements obtained from each plaque. Demographic and clinical characteristics and plaque stiffness were compared according to smoking status, and correlations between smoking status and plaque stiffness were evaluated. Results: A total of 396 SWE measurements were obtained from 132 carotid plaques (195 in cigarette smokers and 201 in non-smokers). Plaques in smokers demonstrated significantly greater stiffness than those in non-smokers, as indicated by shear-wave velocity (smokers: median 4.17 m/s, interquartile range (IQR) 1.94 vs. non-smokers: median 2.91 m/s, IQR 1.81, Z = −5.36, p < 0.001). Smoking was positively correlated with shear-wave velocity (r = 0.27, p < 0.001). No significant differences were observed between smokers and non-smokers in age, sex, hypertension, or diabetes mellitus. Conclusions: Cigarette smoking was associated with increased carotid plaque stiffness measured using ultrasound 2D-SWE. These findings suggest that SWE may provide a quantitative imaging marker of smoking-related differences in carotid plaque composition. Larger studies incorporating smoking duration and cumulative exposure are warranted to determine their clinical significance.