High-risk plaque detected on coronary CT angiography predicts acute coronary syndromes independent of significant stenosis in acute chest pain: results from the ROMICAT-II trial

Abstract

Background: It is not known whether high-risk plaque, as detected by coronary computed tomography angiography (CTA), permits improved early diagnosis of acute coronary syndromes (ACS) independently to the presence of significant coronary artery disease (CAD) in patients with acute chest pain.

Objectives: The primary aim of this study was to determine whether high-risk plaque features, as detected by CTA in the emergency department (ED), may improve diagnostic certainty of ACS independently and incrementally 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 (MI).

Methods: We included patients randomized to the coronary CTA arm of the ROMICAT-II (Rule Out Myocardial Infarction/Ischemia Using Computer-Assisted Tomography II) trial. Readers assessed coronary CTA qualitatively for the presence of nonobstructive CAD (1% to 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 (MI or unstable angina pectoris) 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; unstable angina pectoris n = 32). CAD was present in 262 patients (55.5%; nonobstructive CAD in 217 patients [46.0%] and significant CAD with ≥50% stenosis in 45 patients [9.5%]). High-risk plaques were more frequent in patients with ACS and remained a significant predictor of ACS (odds ratio [OR]: 8.9; 95% CI: 1.8 to 43.3; p = 0.006) after adjustment for ≥50% stenosis (OR: 38.6; 95% CI: 14.2 to 104.7; p < 0.001) and clinical risk assessment (age, sex, number of cardiovascular risk factors). Similar results were observed after adjustment for ≥70% stenosis.

Conclusions: In patients presenting to the ED with acute chest pain but negative initial electrocardiogram and troponin, presence of high-risk plaques on coronary CTA increased the likelihood of ACS independent of significant CAD and clinical risk assessment (age, sex, and number of cardiovascular risk factors). (Multicenter Study to Rule Out Myocardial Infarction by Cardiac Computed Tomography [ROMICAT-II]; NCT01084239).

Keywords: acute chest pain; acute coronary syndrome; coronary atherosclerotic plaque; coronary computed tomography.

Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Study population enrollment, exclusion and inclusion.

Figure 2

Probability of having acute coronary syndrome during the index hospitalization according to coronary computed tomography characteristics. Central Illustration: Significant stenosis and high-risk coronary plaque features and their association with probability of having acute coronary syndrome during the index hospitalization. Stenosis ≥50% – Severe stenosis of the mid left anterior descending coronary artery (red arrow). Non-calcified plaque with positive remodeling in the distal right coronary artery (arrowhead). Positive remodeling – The two dotted red lines (image insert) demonstrate the vessel diameters at the proximal and distal reference (both 1.8 mm) and the full red line demonstrates the maximal vessel diameter in the mid portion of the plaque (2.7 mm) – the remodeling index is 1.5 Low HU plaque – Partially calcified plaque in the mid right coronary artery with low

Figure 2

Probability of having acute coronary syndrome during the index hospitalization according to coronary computed tomography characteristics. Central Illustration: Significant stenosis and high-risk coronary plaque features and their association with probability of having acute coronary syndrome during the index hospitalization. Stenosis ≥50% – Severe stenosis of the mid left anterior descending coronary artery (red arrow). Non-calcified plaque with positive remodeling in the distal right coronary artery (arrowhead). Positive remodeling – The two dotted red lines (image insert) demonstrate the vessel diameters at the proximal and distal reference (both 1.8 mm) and the full red line demonstrates the maximal vessel diameter in the mid portion of the plaque (2.7 mm) – the remodeling index is 1.5 Low HU plaque – Partially calcified plaque in the mid right coronary artery with low