Criteria for Carotid Atherosclerotic Plaque Instability

Background: The study aim is to determine the criteria for carotid atherosclerotic plaque instability with the use of an advanced ultrasound technology, immunohistochemical analysis, and electron paramagnetic resonance (EPR) and assess their correlations with histologic results. Methods: A total of 92 patients were included in the study and were examined by ultrasound duplex scanning and ultrasound elastography. Plaques harvested during carotid endarterectomy were obtained for histologic analysis, immunofluorescent assay, and EPR spectroscopic measurements. Results: Multivariate logistic regression analysis showed that plaques with an area >90 mm2 (odds ratio [OR], 4.05; 95% confidence interval [CI], 1.32-13.2; P = 0.006), plaque volume index > 0.6 cm3 (OR, 2.72; 95% CI, 1.05-9.58; P = 0.04), and juxtaluminal black area >8 mm2 (OR, 2.82; 95% CI, 1.22-6. 23; P = 0.02) were statistically significant independent predictors of histologically verified unstable plaques. Unstable plaques occurred in 94% of the patients with these indicators. Significant increases in the number of CD68+ and CD36+ cells (inflammatory markers) and CD31+ cells (neovasculogenesis markers) were revealed in unstable plaques by the immunohistochemical assay. EPR data analysis showed that divalent manganese could serve as a marker of plaque instability. Conclusions: Additional ultrasound criteria, verified by histologic studies, significantly increased the information content for identifying patients with unstable plaques, which can be of great importance in stratifying the risk of ischemic stroke, especially in asymptomatic patients. The degree of calcification is not a mandatory criterion for plaque stabilization.

Automated summary

This study aimed to determine criteria for carotid atherosclerotic plaque instability using advanced ultrasound technology, immunohistochemical analysis, and EPR. The results showed that plaque area, volume index, and specific black area were significant predictors of unstable plaques, with increased inflammatory and neovasculogenesis markers in such plaques. EPR data analysis indicated that divalent manganese could serve as a marker for plaque instability. Overall, additional ultrasound criteria, along with histological studies, can be essential in identifying patients at risk of ischemic stroke.