Objective  To investigate the variations in plaque distribution among individuals with mild carotid artery stenosis, with a focus on gender and age, utilizing data based on a Chinese Atherosclerosis Risk Evaluation Ⅱ (CARE- Ⅱ) study.

Methods  The clinical data of 627 patients with carotid artery stenosis <50% in the CARE- Ⅱ study from January 2012 to December 2014 were retrospectively analyzed, including 399 males and 228 females, aged 60.9±10.0 years. The features of carotid atherosclerotic plaque in individuals with bilateral carotid artery stenosis measuring less than 50% were measured using MRI. The patients were stratified into two cohorts based on gender. Following the protocols outlined in the North American Symptomatic Carotid Endarterectomy Trial, various metrics, including mean wall thickness, mean wall area, mean standardized wall index, wall volume, wall volume percentage, and degree of stenosis of the carotid artery, were computed, alongside the assessment of the pathological features of plaque. The patients were categorized on the basis of age (≤55 years and >55 years), and analysis was conducted to examine gender disparities in carotid plaque characteristics. The clinical data of male and female groups were analyzed using t-tests and χ² tests, whereas the plaque characteristics were compared using Mann-Whitney U tests and χ² tests. Multivariate logistic regression analysis was conducted to examine the association between clinical and imaging factors and the presence of mild carotid artery vulnerable plaque.

Results  The body mass index ((24.50±2.87) kg/m² vs. (23.69±3.52) kg/m²), diastolic blood pressure ((88.63±14.68) mm Hg vs. (84.36±10.81) mm Hg), and the proportion of smoking (69.2% (276/399) vs. 7.5% (17/288)) in the male group were higher than those in the female group, and the differences were statistically significant (t=−2.896, −4.163, χ²=222.008, all P<0.01). Conversely, age ((59.99±9.89) years vs. (62.55±9.87) years), total cholesterol ((4.48±1.09) mmol/L vs. (4.91±1.14) mmol/L), and low-density lipoprotein ((2.80±0.90) mmol/L vs. (3.15±1.06) mmol/L) in the male group were lower than those in the female group (t=3.098, 4.720, 4.152, all P<0.01). The average wall thickness (1.10 (0.96, 1.26) mm vs. 1.00 (0.88, 1.13) mm), average wall area (32.82 (27.08, 37.62) mm² vs. 26.66 (22.38, 31.46) mm²), and wall volume (1024.72 (834.96, 1184.12) mm³ vs. 831.64 (705.22, 959.57) mm³) in the male group were significantly higher than those in the female group, of which the differences were statistically significant (Z=−6.009, −9.217, −8.847, all P<0.001). In addition, the presence of lipid-rich necrotic core, intraplaque hemorrhage, thin fibrous cap and American Heart Association (AHA) type-Ⅵ plaque was prevalent in people over the age of 55. Furthermore, multivariate logistic regression analysis showed that age over 55, the degree of stenosis, and plaque burden were independent risk factors for the formation of AHA type-Ⅵ plaque (95%CI: 1.267~7.891, 1.014~1.061, 1.175~1.311, all P<0.05).

Conclusions  In the cohort of Chinese patients with mild carotid stenosis, male and older adults have higher carotid plaque burden and more vulnerable plaques, providing a basis for stratified management of this population.