Existing practices focus on risk stratification and lipid monitoring for primary and secondary prevention of cardiac events. |
Advances in coronary plaque imaging have led to an increased interest in the identification of high-risk plaque features that are associated with cardiovascular events. |
There is now a broad evidence base identifying plaque, haemodynamic and patient factors associated with coronary event risk. |
Future progress in multi-modal imaging strategies and in our understanding of high-risk plaque features could expand treatment options for coronary disease and improve patient outcomes. |
Introduction
Definitions of High-Risk Plaque
Mechanisms of High-Risk Plaque Formation
Identifying High-Risk Plaque with Imaging
Imaging modality | Advantages | Disadvantages | High-risk plaque features imaged |
---|---|---|---|
Invasive | |||
IVUS | Good temporal/spatial resolution, gold-standard for plaque volume assessment | Composition assessment limited to post-processing, unable to assess cap thickness | Plaque volume, fibrofatty content |
OCT | Best spatial resolution, good for assessing cap thickness | Limited penetrance, unable to visualize entire thickness of vessel | Thin-cap fibroatheroma, plaque composition |
NIRS | Good at quantifying plaque lipid content | Limited at assessing plaque volume or other features | Lipid content |
Non-invasive | |||
CCTA | Good spatial/temporal resolution, assessment of entire coronary tree | Radiation exposure, limited assessment of fibrous cap thickness and inflammation | Napkin ring sign, positive remodelling, microcalcifications, low attenuation plaque |
PET | Assessment of inflammation and calcification | Yet to see widespread clinical use, 18F-fluorodeoxyglucose (18F-FDG) tracer limited by avid myocardium uptake | Plaque inflammation |
MRI | No radiation, emerging molecular probes | Poor spatial/temporal resolution limits current application for coronary assessment | Carotid thickening |
Non-invasive Imaging
Invasive Imaging
High-Risk Plaque Features
Modality | Study (study name or first author) | Year | N | Follow-up (months) | High-risk feature | HR/OR (95% CI) |
---|---|---|---|---|---|---|
CCTA | ICONIC [39] | 2018 | 234 | 38 | Spotty calcification | 1.54 (1.17–2.04 |
Low attenuation | 1.38 (1.05–1.81) | |||||
Positive remodelling | 1.40 (0.96–2.06) | |||||
CCTA | Yamamoto [32] | 2013 | 453 | 40 | Spotty calcification | 2.41 (0.80–7.50) |
Low attenuation | 8.23 (2.41–37.7) | |||||
Positive remodelling | 8.30 (2.83–26.7) | |||||
CCTA | Feuchtner [33] | 2016 | 1469 | 95 | Spotty calcification | 2.25 (1.26–4.04) |
Low attenuation | 4.50 (1.40–14.8) | |||||
Positive remodelling | 2.80 (1.09–7.40) | |||||
Napkin-ring sign | 7.00 (2.00–13.6) | |||||
CCTA | Halon [44] | 2019 | 499 | 110 | Mild calcification | 3.3 (1.5–7.2) |
4th vs 1st quartile plaque volume | 6.9 (1.6–30.8) | |||||
Low attenuation | 7.3 (1.7–32.3) | |||||
CCTA | Motomoya [50] | 2009 | 1057 | 27 | Low attenuation & PR | 22.8 (6.9–75.2) |
CCTA | Otsuka [63] | 2013 | 895 | 28 | Low attenuation | 3.75 (1.43–9.79) |
Napkin-ring sign | 5.55 (2.1–14.7) | |||||
Positive remodelling | 5.25 (2.17–12.7) | |||||
CCTA | Nakanishi [34] | 2014 | 517 | 49 | Low attenuation | 1.82 (1.04–3.09) |
Napkin-ring sign | 3.64 (1.72–7.81) | |||||
Positive remodelling | 1.24 (0.73–2.03) | |||||
CCTA | Otsuka [35] | 2014 | 543 | 41 | Low attenuation | 2.78 (0.98–7.90) |
Napkin-ring sign | 4.63 (1.54–13.9) | |||||
Positive remodelling | 5.12 (1.84–14.3) | |||||
CCTA | Conte [36] | 2016 | 245 | 98 | Low attenuation | 8.45 (2.22–32.21) |
Napkin-ring sign | 12.5 (1.51–103.9) | |||||
Positive remodelling | 3.31 (1.11–9.91) | |||||
IVUS/OCT | PROSPECT 2 [43] | 2021 | 898 | 48 | Plaque burden ≥ 70% | 11.4 (5.6–23.1) |
Maximum LCBI 4 mm > 324.7 | 7.83 (4.13–14.9) | |||||
IVUS | Stone [69] | 2017 | 697 | 40 | Low shear stress | 4.34 (1.89–10.0) |
OCT | COMBINE-OCT [62] | 2021 | 550 | 18 | Thin-cap fibroatheroma | 5.12 (2.12–12.3) |
OCT | CLIMA [45] | 2020 | 1003 | 12 | Thin-cap fibroatheroma | 4.7 (2.4–9.0) |
Macrophage content | 2.7 (1.2–6.1) | |||||
Lipid-arc circumference | 2.4 (1.2–4.8) | |||||
Mean lumen area < 3.5 mm2 | 2.1 (1.1–4.0) | |||||
NIRS | Waksman [55] | 2019 | 1563 | 24 | Maximum LCBI 4 mm > 400 | 4.22 (2.39–7.45) |
NIRS | Oemrawsingh [51] | 2014 | 203 | 12 | LCBI > median | 4.04 (1.33–12.3) |
NIRS | Madder [52] | 2016 | 121 | 12 | Maximum LCBI 4 mm > 400 | 10.2 (3.4–30.6) |
NIRS | Schuurman [53] | 2017 | 275 | 49 | Maximum. LCBI 4 mm > 360 | 3.58 (1.67–7.70) |