High Risk Plaque Features on Coronary CTA

Study Questions:

Does plaque characterization by coronary computed tomography angiography (CCTA) improve prognostic risk stratification over clinical risk factors and luminal stenosis severity?

Methods:

In the CAPIRE (Coronary Atherosclerosis in outlier subjects: Protective and novel Individual Risk factors Evaluation) multicenter prospective study, CCTA was performed in patients with either 0-1 risk factor or ≥3 risk factors for coronary artery disease. The relationship between CCTA plaque characterization and adverse events, including acute coronary syndrome (ACS), cardiac death, or late revascularization, was evaluated. Patients with diabetes as a single risk factor or two risk factors were not enrolled in the study. The study was designed for a 10-year follow-up period; the present results represent an analysis of interim results at 5 years of follow-up.

Results:

There were a total of 522 patients enrolled in the study with available follow-up (mean follow-up 37 ± 10 months). There were adverse events in 22 patients (eight ACS, one cardiac death, 13 late revascularizations). On multivariable analysis, increased total plaque volume, plaque volume <150 Hounsfield units, and plaque volume <30 Hounsfield units were each associated with higher rates of ACS. The latter two were each associated with increased rates of ACS or cardiac death, while all three were also associated with higher rates of ACS, cardiac death, or late revascularization.

Conclusions:

Increased total plaque volume and noncalcified plaque volume on CCTA are associated with a higher risk of adverse events.

Perspective:

This study finds that increased total plaque volume and noncalcified plaque volume on CCTA is associated with higher rates of adverse events. It is limited by the small number of patients with events, particularly as only nine patients experienced “hard” cardiac events (ACS or cardiac death). The data represent an interim analysis of 5-year results in a study planned for 10 years, and it is expected that further follow-up will increase events and statistical power. These findings support the utility of plaque characterization by CCTA to identify higher-risk patients. However, it remains unknown whether treatment strategies incorporating high-risk CCTA findings alter patient outcomes, and future outcome studies are needed.

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Atherosclerotic Disease (CAD/PAD), Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging

Keywords: Acute Coronary Syndrome, Atherosclerosis, Coronary Angiography, Constriction, Pathologic, Coronary Artery Disease, Diagnostic Imaging, Myocardial Ischemia, Outcome Assessment (Health Care), Plaque, Atherosclerotic, Prognosis, Risk Factors, Secondary Prevention, Tomography, X-Ray Computed


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