Near-infrared spectroscopy carotid plaque characteristics and cerebral embolism in carotid artery stenting

Background: Perioperative thromboembolism is the main consideration in carotid artery stenting (CAS). Precise evaluation of carotid plaque components is clinically important to reduce ischaemic complications since CAS mechanically pushes plaque outwards, which releases plaque debris into the bloodstream.

Aims: This study aimed to determine whether high lipid core plaque (LCP) assessed by catheter-based near-infrared spectroscopy (NIRS) is associated with ipsilateral cerebral embolism by diffusion-weighted magnetic resonance imaging during CAS using a first-generation stent.

Methods: Carotid stenosis magnetic resonance (MR) T1-weighted plaque signal intensity ratio (T1W-SIR) followed by NIRS assessment at the time of CAS (using the carotid artery Wallstent) was performed in 117 consecutive patients.

Results: The maximum lipid core burden index (max-LCBI) at minimal luminal areas (MLA; max-LCBI_MLA) and the max-LCBI for any 4 mm segment in a target lesion defined as max-LCBI_area were significantly higher for the post-procedural new ipsilateral diffusion-weighted magnetic resonance imaging (DWI)-positive than negative patients (p<0.001 for all). There was a significant linear correlation between max-LCBI_area and the number of new emboli (r=0.544, p<0.0001). We also found that the second quantile (Q2) of T1W-SIR_MLA had a significantly higher max-LCBI_MLA and a higher incidence of DWI positivity than Q1 and Q3 (p<0.001 for all). Furthermore, max-LCBI_MLA appeared to distinguish between patients with and without postoperative new ipsilateral DWI positivity (AUC 0.91, 95% CI: 0.86-0.96; p<0.0001).

Conclusions: High LCP assessed by NIRS is associated with cerebral embolism by diffusion-weighted imaging in CAS using a first-generation stent.