This retrospective study involved the continuous collection of data from inpatients scheduled for cardiac surgery at Xiamen University Affiliated Cardiovascular Hospital between May 2019 and September 2023. A total of 167 patients were enrolled, including 93 males (55.7%) and 74 females (44.3%), with an age range of 40 to 85 years (mean age: 61.3 ± 8.6 years). Inclusion criteria required patients to have undergone both cranial MRI and carotid ultrasound at our institution. All patients were scheduled for cardiac surgery, and carotid ultrasound was performed as part of routine preoperative screening to assess cerebrovascular risk. Preoperative screening considered patients' cardiovascular risk factors, including hypertension, diabetes, and hyperlipidemia. Exclusion criteria included: (1) incomplete clinical data or poor-quality imaging; (2) acute cerebrovascular events; (3) non-vascular causes of white matter lesions, such as metabolic brain diseases; (4) diagnosed neurodegenerative diseases (e.g., Parkinson's disease, Alzheimer's disease); and (5) inconsistencies in diagnostic conclusions by ultrasound specialists (Figure 1). Although routine head/neck CTA (CT angiography) was not performed, patients with ≥50% carotid stenosis or abnormal ultrasound results were further evaluated with imaging studies (e.g., CTA or MRI angiography) as clinically indicated. Given the high prevalence of intracranial stenosis in the Asian population, both clinical background and carotid plaque characteristics were considered to comprehensively assess cerebrovascular health and small vessel disease burden. The study was approved by the Medical Ethics Committee of Xiamen University Affiliated Cardiovascular Hospital (2023, ethical approval number 35).

Clinical data were collected from patients, including general information such as sex, age, body mass index (BMI), history of coronary artery disease, history of hypertension, history of diabetes, history of hyperlipidemia, as well as smoking and alcohol consumption histories. Additionally, cranial MRI and carotid ultrasound images were obtained. Based on the cranial MRI results, the study participants were classified into two groups: those with cerebral small vessel disease (CSVD) and those without cerebral small vessel disease (Non-CSVD). The differences in general characteristics and the echo features of carotid plaques between the two groups were then compared to elucidate the relationship between carotid plaque characteristics and CSVD.

Cranial MRI was conducted using the GE Healthcare SIGNA Pioneer 3.0T and SIGNA Architect 3.0T superconducting magnetic resonance imaging systems. The imaging sequences included axial diffusion-weighted imaging (DWI), T2 fluid-attenuated inversion recovery (FLAIR), T2^*-weighted gradient-recalled echo (GRE), susceptibility-weighted imaging (SWI), as well as T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) (14). The established radiological markers for the diagnosis of cerebral small vessel disease included recent small subcortical infarcts (RSSI), vascular lacunes, vascular-related white matter hyperintensities (WMHs), enlarged perivascular spaces (EPVS), cerebral microbleeds (CMBs), and brain atrophy (15). These criteria facilitate a comprehensive assessment of the structural changes associated with CSVD, thereby enhancing diagnostic accuracy.

Ultrasound examinations were performed using the Philips EPIQ 7 diagnostic ultrasound system, equipped with linear array transducers operating at frequencies ranging from 5.0 to 12.0 MHz. Two-dimensional ultrasound combined with color Doppler ultrasound was utilized to conduct both longitudinal and transverse scans of the carotid arteries, subclavian arteries, and vertebral arteries. The degree of carotid stenosis and plaque characteristics were evaluated following the Mannheim Carotid Intima-Media Thickness and Plaque Consensus (16). Based on the echo characteristics of the vascular wall, carotid plaques were categorized into three types according to the echogenicity of the plaque contents: (1) hypoechoic plaques: those with echogenicity lower than that of the intima-media layer of the vascular wall; (2) isoechoic plaques: those with echogenicity consistent with that of the intima-media layer; and (3) hyperechoic plaques: those with echogenicity equal to or slightly higher than that of the adventitial layer of the vascular wall (17). All examinations were conducted by operators of the same professional qualification level to ensure consistency and reliability in the assessment.

Data was conducted by SPSS 29.0. Initially, univariate analyses were performed to compare the general characteristics and carotid echo features between the two patient groups. Continuous data conforming to a normal distribution were expressed as mean ± standard deviation (x ± s) and analyzed using independent samples t-tests. Categorical data were presented as counts (percentage) and analyzed using the χ² test or Fisher's exact test as appropriate. All tests were two-tailed, with a significance level set at α = 0.05. Variables demonstrating statistically significant differences (P < 0.05) in clinical characteristics between the two groups were subsequently subjected to multivariate logistic regression analysis to identify potential risk factors for cerebral small vessel disease. P < 0.05 was considered statistically significant.

Initially, we analyzed the differences in general characteristics between the two patient groups. The results indicated no statistically significant differences in sex, age, diabetes, hyperlipidemia, smoking, or alcohol consumption (P > 0.05). However, the BMI of the CSVD group was higher than that of the Non-CSVD group [(24.1 ± 3.4) kg/m² vs. (22.8 ± 3.2) kg/m²; t = 2.237, P = 0.027]. Additionally, the prevalence of coronary artery disease and hypertension was significantly higher in the CSVD group compared to the Non-CSVD group (both P < 0.05; Table 1).

Understanding the echo characteristics of carotid plaques in different patient populations is crucial for assessing stroke risk and guiding treatment strategies. In this study, we found that the proportion of patients in the CSVD group without carotid plaques was significantly lower than that in the Non-CSVD group (P < 0.001). Additionally, the prevalence of hypoechoic and isoechoic plaques was significantly higher in the CSVD group compared to the Non-CSVD group (both P < 0.05; Table 2).

In the analysis of the aforementioned comparisons, variables with P < 0.05, including BMI, coronary artery disease, hypertension, hypoechoic plaques, and isoechoic plaques, along with other clinically significant variables identified by the researchers such as hyperlipidemia, were included in a multivariate logistic regression model. The results indicated that carotid isoechoic plaques (OR = 2.139, 95% CI 1.421–3.219, P < 0.001) and carotid hypoechoic plaques (OR = 1.687, 95% CI 1.206–2.359, P = 0.002) were independent risk factors for CSVD (Table 3).