Abstract 2004: Usefulness of Coronary CT Angiography in the Early Triage of Patients with Acute Chest Pain

Abstract

Background: Early triage of patients with acute chest pain in the emergency department (ED) may be improved by rapid noninvasive assessment of coronary artery disease (CAD) by coronary computed tomography angiography (CTA). We sought to determine the usefulness of coronary CTA for the early triage of patients with acute chest pain but an inconclusive initial ED evaluation. Methods: Single center, double-blinded observational cohort study in the ED of a large tertiary academic hospital enrolling 368 consecutive patients with acute chest pain and inconclusive initial ED evaluation (normal initial troponin and an initial ECG without evidence of myocardial ischemia) who were awaiting hospital admission between May 2005 and May 2007. All patients underwent 64-slice contrast-enhanced coronary CTA prior to hospital admission with caregivers and patients blinded to the results of the examination. Diagnostic accuracy and discriminatory power of coronary CTA findings (coronary plaque and stenosis [>50% luminal narrowing]) for acute coronary syndrome (ACS) during index hospitalization and major adverse cardiac events (MACE) during 6- month follow-up. Results: Among 368 patients (mean age 53±12 years, 61% male) 31 (8%) developed ACS but no MACE occurred during follow-up. Fifty percent (n=183) of the study population had neither plaque nor stenosis, a finding which had 100% negative predictive value (95% confidence interval [CI]: 98 to 100%) for ACS. In adjusted analysis, the extent of coronary plaque and presence of stenosis were associated with an increased risk for ACS (OR: 1.28, 95% CI: 1.14 to 1.43 and OR: 11.69, 95% CI: 4.4 to 31.0; respectively). Coronary CT findings (no CAD, plaque but no stenosis, and stenosis) discriminated patients at low, intermediate, or high risk of ACS (OR: 8.65, 95% CI: 3.69 to 20.26; AUC: 0.91). Conclusion : Half of the patients with acute chest pain and low to intermediate likelihood of ACS have no CAD and may be safely discharged directly from the ED. Coronary CT has excellent discriminatory power in defining patient risk for ACS.