Plaque Characterization by Coronary CT Angiography
Are high-risk plaque (HRP) characteristics on coronary computed tomography angiography (CTA) associated with risk of acute coronary syndrome (ACS)?
This study examined 3,158 patients undergoing coronary CTA, and evaluated the rate of ACS in patients with versus without HRP (positive remodeling and/or low-attenuation plaque) and severe stenosis (≥70%) on CTA. Mean follow-up was 3.9 ± 2.4 years. A subset of 449 patients had a repeat CTA, and the relationship between plaque progression and ACS was also examined.
Events were observed in 2.8% (88/3,158) of patients. ACS was observed in 16.3% (48/294) of patients with HRP versus 1.4% (40/2,864) of patients without HRP (p < 0.001), and in 5.5% (36/659) of patients with severe stenosis versus 2.1% (52/2,499) of patients without severe stenosis (p < 0.001). On multivariable analysis, the presence of severe stenosis without HRP was not associated with a higher risk of events (p = 0.12), while HRP without severe stenosis (hazard ratio [HR], 13.1; 95% confidence interval [CI], 3.8-82.7; p < 0.001) and HRP with severe stenosis (HR, 17.2; 95% CI, 4.9-109.5; p < 0.001) were each associated with an increased risk of ACS. Among individuals with plaque progression on serial CTA, the only variables independently associated with ACS were prior ACS (HR, 8.4; 95% CI, 1.1-209.6; p = 0.04) and the presence of plaque progression (HR, 33.4; 95% CI, 4.1-78.0; p < 0.001).
The authors concluded that HRP characteristics or plaque progression on CTA are associated with an increased risk of ACS.
Prior literature by this group and others has demonstrated that specific plaque characteristics on CTA may be associated with an increased risk of adverse events including ACS. This study expands on these prior studies by following patients over a longer period of time and by evaluating the significance of plaque progression on CTA. It must be acknowledged that this is a retrospective cohort study, and as such, it is susceptible to selection bias. Nevertheless, the results are intriguing. At present, we have many tests that can accurately identify patients with coronary artery disease, but we have significant difficulty determining patients at risk of coronary events. This study highlights the limited associations between cardiovascular risk factors or luminal stenosis and the risk of adverse events, and suggests that findings such as plaque progression or high-risk plaque could help us better identify patients at risk. For now, it may be reasonable to report these findings when they are observed, given their potential association with risk. Prospective studies are needed, however, to validate these findings, and to determine whether these results change management or alter outcomes.
Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging
Keywords: Acute Coronary Syndrome, Angiography, Constriction, Pathologic, Coronary Artery Disease, Myocardial Ischemia, Plaque, Atherosclerotic, Risk Factors, Tomography
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