Introduction

Despite ongoing studies, the relationship of plaque echomorphology with increased risk of stroke in patients undergoing carotid angioplasty and stenting (CAS) remains elusive. The aim of this study is to examine whether carotid plaque echolucency is associated with greater plaque instability as determined by the quantification of captured embolic debris in CAS patients.

Methods

A total of 41 consecutive CAS patients with high-grade carotid stenosis were prospectively evaluated. B-mode images for 21 patients were available for analysis. Plaque echolucency was determined by grayscale median (GSM), a computer-assisted measure of echogenicity. Images were standardized with a GSM value of 0–5 for the vessel lumen and 185–195 for the adventitia. Echolucent (EL) plaques were defined by GSM < 25, and echogenic (EG) plaques were defined by GSM ≥ 25. Protective filters were visualized by stereomicroscopy along three perpendicular axes and quantified through video imaging software. Because of heterogeneity in particle shape, individual particle sizes were determined by greatest length.

Results

Mean GSM was 45.5, and 10% plaques were echolucent. Particulate debris was detected in all filters. Plaques with lower GSM were associated with a greater number of particles (EL: 33.5 ± 10.6 particles, EG: 14.0 ± 10.3 particles; p = 0.02). Echolucent plaques also demonstrated particles of greater size: maximum size (EL: 3490 ± 1954 μm, EG: 1026 ± 1186 μm; p = 0.015) and number of particles >1000 μm (EL: 3.5 ± 2.1 particles, EG: 0.7 ± 1.4 particles; p = 0.019).

Conclusions

Echolucent carotid plaques, as determined by GSM, may cause increased embolization of greater-sized embolic debris during CAS. Our study confirms previous findings that suggest that a GSM cut-off point of 25 may be linked with the release of more embolic debris. Therefore, increased plaque echolucency may place patients at greater risk for perioperative embolic events, making patients with such lesion characteristics more likely to experience postprocedural neurologic complications.