Abstract 681: Characteristics of Atherosclerotic Plaque Burden in Patients With and Without Acute Coronary Syndrome Presenting With Acute Chest Pain to the Emergency Department
Background: Coronary computed tomography (CT) may improve the early triage of patients with acute chest pain in the emergency department (ED). The aim of this study was to compare the presence and extent of coronary atherosclerotic plaque as detected by coronary CT in patients with and without acute coronary syndromes (ACS).
Methods: The study was designed as a prospective, observational cohort study in patients with acute chest pain but negative cardiac biomarkers and no diagnostic ECG changes, admitted to rule out myocardial ischemia. All patients underwent coronary CT prior to hospital admission. The presence of coronary plaque was treated as a dichotomous outcome, and the extent of CAD was defined as number of (1) coronary segments with plaque, or (2) major coronary arteries with plaque detected by MDCT as assessed by two independent observers. The clinical outcome (ACS) was adjudicated by a review committee using established AHA criteria; subjects with history of CAD (stent placement, bypass) were excluded.
Results: Among 368 patients with acute chest pain (mean age 53±12 years, 61% male) 31 patients were determined to have ACS (8%). None of the 183 subjects without plaque (50%) had an ACS. Among the remaining 185 subjects (mean age 58.0±11.5 years, 68% male) in whom coronary plaque was detected, patients with ACS had a significantly more plaque (7.2±3.7 vs. 4.2±3.4, p<0.0001 segments) as compared to subjects without ACS. Similar results were seen for calcified plaque and non-calcified plaque (6.5±3.7 vs. 3.6±3.5 segments, p<0.0001; and 3.6±3.2 vs. 1.8±2.2 segments, p<0.0001, respectively). In addition, the rate of ACS increased with the number of major coronary arteries with plaque (1-vessel: 6.8%, 2-vessels: 10.6%, 3 vessels: 30.8%, and 4-vessels: 25%; p<0.01). In contrast, the ratio of non-calcified to calcified plaque was not different between patients with and without ACS (0.68±0.6 vs. 0.54±0.72, p=0.31).
Conclusions: The extent of coronary plaque differs between subjects with and without ACS among patients presenting with acute chest pain. Detailed assessment of the extent and composition of coronary plaque may be helpful to assess risk of ACS among patients with acute chest pain but inconclusive initial ED evaluation.