The relationship among extent of lipid-rich plaque, lesion characteristics, and plaque progression/regression in patients with coronary artery disease: a serial near-infrared spectroscopy and intravascular ultrasound study

Abstract

Aims: To evaluate the relationship between lipid content and plaque morphometry as well as the process of lesion progression and regression in patients with significant coronary artery disease.

Methods and results: The present study, using data from the YELLOW trial, was conducted in patients having significant coronary lesions (fractional flow reserve <0.8) who underwent serial intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) at baseline and after 7 weeks. For each coronary plaque (≥50% plaque burden that was ≥5 mm in length), we evaluated plaque characteristics and the extent of lipid-rich plaque [LRP, defined as the 4 mm long segment with the maximum lipid-core burden index (maxLCBI4 mm)] on NIRS. Among 66 patients (age 63.0 ± 10.1 years; 82% statin use at baseline), 94 plaques were identified. The extent of LRP at baseline was positively correlated with IVUS plaque burden (r = 0.317, P = 0.002). A large LRP (maxLCBI4 mm ≥500) was present only in plaques with a large plaque burden (≥70%). Multivariate analysis demonstrated that plaque burden was the best predictor of the extent of LRP (P < 0.001). In lesions with a large plaque burden and a large amount of LRP at baseline, a reduction in LRP was seen in all lesions in patients receiving intensive statin therapy (P = 0.004) without a significant change in plaque burden.

Conclusions: Coronary lesions containing a large amount of LRP also had a large plaque burden. Short-term regression of LRP (without a change in plaque burden) was observed mainly in plaques with a large plaque burden and a large amount of LRP at baseline.

Clinical trial registration: http://www.clinicaltrials.gov. Unique identifier: NCT01567826.

Keywords: Intravascular ultrasound; Lipid-rich plaque; Near-infrared spectroscopy; Plaque regression.

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Figures

Figure 1:

Representative NIRS and corresponding IVUS images. A region of interest was chosen from the baseline IVUS as a segment with a ≥50% plaque burden that was ≥5 mm in length (left). On the right is the corresponding NIRS segment identified at baseline and follow-up. MLA, minimum lumen area.

Figure 2:

The relationship between maxLCBI4 mm (NIRS) and plaque burden (IVUS). The dotted horizontal line indicates a maxLCBI4 mm of 500, and the vertical dotted line indicates a plaque burden of 70% at the MLA site. Importantly, there is no plaque having a plaque burden of <70%, but a maxLCBI4 mm ≥500.

Figure 3:

Change in the extent of lipid contents within coronary plaques from baseline to follow-up (mean, 7 weeks) evaluated by serial NIRS analysis. Lipid-rich plaque regression was identified in plaques having large lipid contents at baseline (maxLCBI4 mm ≥500) receiving intensive statin therapy. *P = 0.004.