The Impact of Carotid Artery Plaque Echogenicity on the Rate of Solid Cerebral Microembolism during Carotid Artery Stenting

Aims: Carotid artery stenting (CAS) may be associated with clinically silent cerebral embolic events. We prospectively evaluated the association of the sonographic echogenicity of carotid artery plaque with solid cerebral microembolism during CAS.

Methods: Twenty-seven patients with symptomatic high-grade carotid artery stenoses scheduled to undergo CAS were included in the study. A computer-assisted measure of echogenicity, the grey scale median (GSM), was used to quantify the echogenicity of carotid artery plaques on normalized sonographic B-mode images. Dual-frequency transcranial Doppler sonography was used to detect solid cerebral microemboli during CAS. No embolus protection devices were used.

Results: Solid cerebral microemboli were detected in 17 of the 27 patients. In patients with solid microemboli, GSM was lower (median, 37; 95% CI, 27.2 to 48.7) than in patients without solid microemboli (median, 66; 95% CI, 39.8 to 76.6) (p<0.05). ROC analysis identified a GSM cutoff value of 50 as threshold for the identification of patients at high risk of solid microembolism during CAS. In patients with echolucent plaques (GSM<50), the rate of solid microembolism was higher (85%) than in patients with echogenic plaques (GSM≥50) (43%) (p<0.05).

Conclusion: CAS of echolucent carotid artery plaques is associated with a higher rate of solid cerebral microembolism than CAS of echogenic carotid plaques.