Lipid Core Plaque Distribution Using Near-infrared Spectroscopy Is Consistent with Pathological Evaluation in Carotid Artery Plaques

Carotid artery stenting (CAS) is performed as a treatment for carotid artery stenosis. However, lipid-rich plaques cause embolic complications and sequelae. Near-infrared spectroscopy (NIRS) can identify lipid components by applying a near-infrared absorption pattern, and the distribution of lipid components can be evaluated as the maximum lipid core burden index (maxLCBI). Intravascular ultrasound (IVUS) equipped with NIRS has been clinically applied recently, and its diagnostic usefulness and validation have been reported for coronary arteries; however, its consistency with actual pathological diagnosis in carotid artery lesions has not been validated. In this study, we investigated the consistency between the maxLCBI values and histopathological diagnoses. Patients with cervical carotid artery stenosis who underwent carotid endarterectomy (CEA) were examined in this prospective study. Pathological diagnosis was determined after NIRS evaluation, which was performed on the extracted plaques ex vivo. The histological slices of decalcified and paraffin-embedded sections were stained by hematoxylin-eosin (HE) and Elastica van Gieson (EVG), and for low-density lipoprotein (LDL), C-reactive protein (CRP), CD68, and glycophorin A. The correlation between maxLCBI values and histological findings. Seventy lesions assessed by NIRS were pathologically analyzed. There was a positive linear correlation between maxLCBI values and pathological findings as determined by HE (angle), HE (area%), EVG, CRP, and CD68 staining (respectively, r = 0.624, p <0.001; r = 0.578, p <0.001; r = 0.534, p <0.001; r = 0.723, p <0.001; r = 0.653, p <0.001). In conclusion, the maxLCBI values assessed by NIRS showed a significant positive linear correlation with pathological evaluations in carotid lesions. The maxLCBI values in carotid arteries are consistent with pathological evaluations.