Contrast-enhanced ultrasound to predict the risk of microembolization during carotid artery stenting

Cerebral microembolization, one of the most frequent complications of carotid artery stenting, is associated with an increased risk of peri- and post-procedural stroke and transient ischemic attack and a mid-term risk of neurocognitive decline. A valuable tool to evaluate carotid plaque instability and risk of embolization is contrast-enhanced ultrasound. With this prospective study we sought to determine the correlation between contrast enhancement of the plaque and cerebral microembolization after carotid stent deployment and to evaluate the clinical impact of the neurological injury.

Thirty-five consecutive patients with carotid artery stenosis and indications for endovascular stenting were enrolled. Before the procedure, patients were evaluated with contrast-enhanced ultrasound to define plaque enhancement (signal intensity). All endovascular procedures were performed under cerebral filter protection. Diffusion-weighted magnetic resonance imaging scans to detect microemboli were obtained before and 48 h after the stent deployment. The Ray auditory verbal learning test to assess neurocognitive function was administered before and 1 month after the procedure.

Nineteen patients (54 %) developed new cerebral ischemic lesions after carotid artery stenting. Contrast enhancement of the plaque was greater in the patients with post-procedural microembolization than in those without it [maximum signal intensity 26 ± 7.7 vs. 21 ± 5.2, respectively, (p = 0.039), mean signal intensity, 20.7 ± 6.1 vs. 16.5 ± 5.3, respectively (p = 0.048)]. No correlation was found between neurocognitive test scores and microembolization or plaque enhancement.

Contrast enhancement of the carotid plaque is strongly associated with post-procedural microembolization and for this reason it can be considered a reliable tool for an accurate selection of patients undergoing this endovascular treatment. However, the neurocognitive test scores performed in this study are not enough sensible to appreciate the impact of the neurological injury on the day life activities.