Clinical Research
Atherosclerosis Evaluation by Ultrasound
In Vivo Intravascular Ultrasound-Derived Thin-Cap Fibroatheroma Detection Using Ultrasound Radiofrequency Data Analysis

https://doi.org/10.1016/j.jacc.2005.07.064Get rights and content
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Objectives

The purpose of this study was to assess the prevalence of intravascular ultrasound (IVUS)-derived thin-cap fibroatheroma (IDTCFA) and its relationship with the clinical presentation using spectral analysis of IVUS radiofrequency data (IVUS-Virtual Histology [IVUS-VH]).

Background

Thin-cap fibroatheroma lesions are the most prevalent substrate of plaque rupture.

Methods

In 55 patients, a non-culprit, non-obstructive (<50%) lesion was investigated with IVUS-VH. We classified IDTCFA lesions as focal, necrotic core-rich (≥10% of the cross-sectional area) plaques being in contact with the lumen; IDTCFA definition required a percent atheroma volume (PAV) ≥40%.

Results

Acute coronary syndrome (ACS) (n = 23) patients presented a significantly higher prevalence of IDTCFA than stable (n = 32) patients (3.0 [interquartile range (IQR) 0.0 to 5.0] vs. 1.0 [IQR 0.0 to 2.8], p = 0.018). No relation was found between patient’s characteristics such as gender (p = 0.917), diabetes (p = 0.217), smoking (p = 0.904), hypercholesterolemia (p = 0.663), hypertension (p = 0.251), or family history of coronary heart disease (p = 0.136) and the presence of IDTCFA. A clear clustering pattern was seen along the coronaries, with 35 (35.4%), 31 (31.3%), 19 (19.2%), and 14 (14.1%) IDTCFAs in the first 10 mm, 11 to 20 mm, 21 to 30 mm, and ≥31 mm segments, respectively, p = 0.008. Finally, we compared the severity (mean PAV 56.9 ± 7.4 vs. 54.8 ± 6.0, p = 0.343) and the composition (mean percent necrotic core 19.7 ± 4.1 vs. 18.1 ± 3.0, p = 0.205) of IDTCFAs between stable and ACS patients, and no significant differences were found.

Conclusions

In this in vivo study, IVUS-VH identified IDTCFA as a more prevalent finding in ACS than in stable angina patients.

Abbreviations and Acronyms

ACS
acute coronary syndrome
IDTCFA
intravascular ultrasound-derived thin-cap fibroatheroma
IQR
interquartile range
IVUS
intravascular ultrasound
IVUS-VH
Intravascular Ultrasound-Virtual Histology
LAD
left anterior descending coronary artery
LCX
left circumflex artery
PAV
percent atheroma
RCA
right coronary artery
ROI
region of interest
TCFA
thin-cap fibroatheroma

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