Echogenicity of carotid plaques as a predictor of regression following lipid-lowering therapy

Abstract

Objective: Atherosclerotic plaque regression under lipid-lowering therapy shows considerable individual variation, and the factors influencing this variability remain incompletely understood. This study aimed to investigate the relationship between carotid plaque echogenicity and plaque regression in patients receiving lipid-lowering therapy, and to identify ultrasound characteristics that might predict plaque regression.

Methods: A total of 838 patients with carotid plaques receiving lipid-lowering therapy were enrolled between July 2020 and May 2024 and followed up for 12 months. Carotid ultrasound was performed at baseline and follow-up to evaluate plaque characteristics. Plaque regression was defined as meeting any of the following criteria: (1) reduction in plaque area ≥ 5%, (2) decrease in plaque thickness ≥ 0.4 mm, or (3) reduction in plaque number, as assessed by vascular ultrasound imaging. Plaque echogenicity was classified into three types: hypoechoic, hyperechoic, and mixed echogenicity. Cox proportional hazards regression analysis was performed to assess the association between plaque echogenicity and plaque regression, adjusting for potential confounding factors.

Results: Hypoechoic plaques showed higher rates of regression (72.8%) compared to hyperechoic (37.7%) and mixed echogenicity plaques (50.0%) (p < 0.001). After adjusting for confounding variables, hypoechoic plaques exhibited greater odds of regression compared to hyperechoic plaques (adjusted HR = 4.52, 95% CI: 3.18-6.43, p < 0.001). Additionally, the median percentage reduction in plaque size was more pronounced in hypoechoic plaques, (15.2%, IQR: 7.7-22.3%) compared with other echogenicities (p < 0.001).

Conclusion: Carotid plaque echogenicity is strongly associated with the likelihood plaque regression, with hypoechoic plaques exhibiting higher regression rates and greater reductions in plaque size. These findings may help guide personalized treatment strategies and improve risk assessment.

Keywords: Atherosclerosis; Carotid ultrasound; Echogenicity; Plaque regression.

Fig. 1

Three types of plaques. A: Representative ultrasound image of a hypoechoic carotid plaque. The image shows a typical hypoechoic plaque with low echogenicity (darker appearance) compared to the surrounding tissues, demonstrating the characteristic features associated with higher regression potential (72.8% regression rate in this study). The hypoechoic nature suggests a lipid-rich composition that may be more responsive to lipid-lowering therapy. Note the relatively homogeneous internal structure and well-defined boundaries. Scale bar = 4.0 cm

Fig. 1

B: Representative ultrasound image of a hyperechoic carotid plaque. The image demonstrates a typical hyperechoic plaque characterized by high echogenicity (brighter appearance) compared to surrounding tissues, with well-defined boundaries and relatively homogeneous internal structure. This type of plaque typically shows lower regression rates (37.7%) compared to hypoechoic plaques (72.8%) following lipid-lowering therapy. Scale bar represents 5 mm

Fig. 1

C: Representative ultrasound image of a mixed echogenicity carotid plaque. The image demonstrates a plaque with heterogeneous composition, containing both hypoechoic (darker) and hyperechoic (brighter) regions within the same plaque. This type of plaque showed intermediate regression rates (50.0%) compared to hypoechoic (72.8%) and hyperechoic (37.7%) plaques following lipid-lowering therapy. The heterogeneous appearance suggests a complex plaque composition with both lipid-rich and fibrotic components. Scale bar = 3.0 cm

Fig. 2

Representative ultrasound images demonstrating plaque regression in a hypoechoic carotid plaque following lipid-lowering therapy.A: Baseline ultrasound image showing a hypoechoic plaque with a thickness of 0.638 cm (March 2024)

Fig. 2

B: Follow-up ultrasound image after 8 months of lipid-lowering therapy showing significant regression with plaque thickness reduced to 0.106 cm (November 2024), representing an 83.4% reduction. This case exemplifies the high regression potential of hypoechoic plaques, which showed a significantly higher regression rate (72.8%) compared to other plaque types in our study. Scale bars = 3.0 cm

Fig. 3

The study flowchart

Fig. 4

The forest plot of subgroup analyses