Background To determine whether high-risk plaque as detected by coronary computed tomography angiography (CTA) permits improved early diagnosis of acute coronary syndrome (ACS) independent to the presence of significant CAD in acute chest pain patients. Objectives The primary aim was to determine whether high-risk plaque features, as detected by CTA in the emergency department, may improve diagnostic certainty of ACS independent and incremental to the presence of significant CAD and clinical risk assessment in patients with acute chest pain but without objective evidence of myocardial ischemia or myocardial infarction. Methods We included patients randomized to the CCTA arm of ROMICAT II trial. Readers assessed coronary CTA qualitatively for the presence of non-obstructive CAD (1-49% stenosis), significant CAD (≥50% or ≥70% stenosis), and the presence of at least 1 of the high-risk plaque features (positive remodeling, low < 30 Hounsfield Units plaque, napkin-ring sign, spotty calcium). In logistic regression analysis, we determined the association of high-risk plaque with ACS [myocardial infarction (MI) or unstable angina pectoris (UAP)] during the index hospitalization and whether this was independent of significant CAD and clinical risk assessment. Results Overall 37 of 472 patients who underwent coronary CTA with diagnostic image quality (mean age 53.9±8.0 years, 52.8% men) had ACS (7.8%; MI n=5, UAP n=32)]. CAD was present in 262 (55.5%) patients [non-obstructive CAD 217 (46.0%) patients, significant CAD with ≥50% stenosis 45 (9.5%) patients]. High-risk plaques were more frequent in patients with ACS and remained a significant predictor of ACS (OR 8.9, 95% CI 1.8-43.3, p=0.006) after adjusting for ≥50% stenosis (OR 38.6, 95% CI 14.2-104.7, p<0.001) and clinical risk assessment (age, gender, number of cardiovascular risk factors). Similar results were observed after adjusting for ≥70% stenosis. Conclusions In patients presenting to the ED with acute chest pain but negative initial electrocardiogram and troponin, presence of high-risk plaque on coronary CTA increases the likelihood of ACS independent of significant CAD and clinical risk assessment (age, gender, and number of cardiovascular risk factors).

clinicaltrials.gov Indentifier: NCT01174550.