Long-term changes after carotid stenting assessed by intravascular ultrasound and near-infrared spectroscopy

Abstract

Background: Long-term effect of carotid stenting (CAS) on the stabilization of the plaque is almost unrecognized. Vascular healing and remodeling might seal the atherosclerotic plaque with neointimal hyperplasia decreasing the vulnerability. We aimed to assess long-term change in the lipid signal, stent and luminal dimensions and restenosis after CAS with the intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging.

Methods: We performed follow-up angiography and NIRS-IVUS imaging of 58 carotid stents in 52 patients. Median time from CAS to the follow-up examination was 31 months (range, 5-56). The lipid signal of the stented segment was calculated from a NIRS-derived chemogram (a spectroscopic map) as the lipid core burden index (LCBI, a dimensionless number from 0 to 1,000). Planimetric and volumetric measurements from IVUS were performed to assess change in minimal stent area (MSA), minimal luminal area (MLA), stent and luminal volume, late stent expansion and percentage in-stent restenosis (ISR) volume.

Results: During the follow-up period, the mean (±SD) LCBI significantly decreased from 32±56 to 17±27 (P=0.002). The mean stent volume significantly increased from 717±302 to 1,019±429 mm3 (P<0.001) with mean stent expansion 43%±24%. The mean luminal volume increased from 717±302 to 760±359 mm3 (P=0.025) due to ISR encroaching 26%±15% of the stent volume.

Conclusions: Lipid signal decreased during the follow-up period suggesting stabilization of the plaque. Late stent expansion was balanced with neointimal hyperplasia.

Trial registration: The trial is registered under clinicaltrials.gov NCT03141580.

Keywords: Carotid stenting; intravascular ultrasound; lipid core burden index; near-infrared spectroscopy; plaque stabilization.

Conflict of interest statement

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/cdt-21-160). The authors have no conflicts of interest to declare.

2021 Cardiovascular Diagnosis and Therapy. All rights reserved.

Figures

Figure 1

Angiogram of carotid artery with implanted stent (A) and corresponding longitudinal (B) and cross-sectional (C) IVUS imaging with NIRS-derived chemogram.

Figure 2

Quantitative IVUS assessment (mean ± SD) of the change in (A) minimal luminal area, (B) minimal stent area, (C) luminal volume and (D) stent volume during the follow-up period.

Figure 3

Scatter plots with Pearson’s correlation between (A) percentage stent expansion and percentage in-stent restenosis (ISR) volume and (B) baseline lipid core burden index (LCBI) and percentage ISR volume.

Figure 4

Scatter plots with Pearson’s correlation between length of the follow-up and (A) percentage in-stent restenosis (ISR) volume and (B) stent expansion.

Figure 5

Quantitative NIRS assessment (mean ± SD) of the change in lipid core burden index (LCBI) during the follow-up period (A) in the entire stented segment and (B) maximal LCBI in any 4-mm segment of the chemogram. The middle bar represents mean and the error bars represent standard deviation.