Size and nature of emboli produced during carotid artery angioplasty and stenting: in vivo study

Abstract

Aim: Microembolization continues to be a major risk for patients undergoing carotid artery stenting (CAS) of high-grade atherosclerotic carotid stenoses. Further insight into the characteristics and significance of these embolized particles was deemed necessary. We aimed to assess the size and composition of debris captured by filters during CAS and to determine if this could be predicted using standard imaging techniques.

Methods: 20 patients (10 symptomatic, 15 men, mean age 64.6 years) undergoing CAS for high-grade ICA stenosis were recruited. All underwent pre-operative CT angiography and calcium scoring. All underwent CAS using the same protocol. A filter-type embolic protection device (EPD) was used and retrieved post-operatively and captured particles underwent analysis using a Scanning Electron Microscope (SEM) for counting, sizing, and composition.

Results: Clinical. Debris was found on 100% of filters when analysed with SEM. There were non-significant trends for CAS in asymptomatic patients to produce a greater number of smaller, calcified particles while in symptomatic patients we observed larger, lipid-rich particles. When stratified according to pre-operative calcium scores, 'calcium-rich' plaques produced significantly greater numbers of emboli captured on the EPD (p = 0.02).

Conclusions: Filter-type EPDs collect debris of significant quantity and size during the CAS procedure as performed in our institution. The collected material was likely dislocated from the atherosclerotic plaque. CT calcium scoring allows us to predict the nature of material captured by the EPD. These data may allow the clinician to individualise care during CAS and thus reduce peri-operative risk.