Abstract 1751: Coronary Plaque Characteristics on Multi-Slice Computed Tomography in Stable Versus Unstable Angina Pectoris
Objectives: Previous studies suggest that plaque configuration rather than the degree of stenosis may predict risk for coronary events. Multi-Slice Computed Tomography (MSCT) allows evaluation of coronary plaques. The purpose of the study was to evaluate the differences in coronary plaque characteristics on MSCT in patients with stable angina pectoris (SAP) and unstable angina pectoris (UAP).
Methods: MSCT was performed in 203 patients (128 men, age 58 ± 11 yrs) with known and suspected coronary artery disease (CAD) (64-slice MSCT in 149 patients). Plaque extent was defined as number of diseased coronary segments, number of segments with non-obstructive and obstructive (≥ 50% luminal narrowing) plaques. Also, plaques were classified as non-calcified, mixed or calcified. Plaque characteristics were compared in patients with SAP (n = 168) and UAP (n = 35). The association between plaque characteristics and clinical presentation was determined with multivariate linear regression (with correction for age, gender and risk factors of CAD).
Results: Coronary plaques were detected in 159 patients. The extent of CAD, expressed as number of diseased segments, segments with non-obstructive and obstructive plaques was significantly higher in patients with UAP as compared to patients with SAP, being 6 ± 3 vs 4 ± 3 (p < 0.0001), 2 ± 2 vs 1 ± 1 (p < 0.001) and 4 ± 2 vs 3 ± 3 (p = 0.001), respectively. In patients with UAP more non-calcified (23% vs 17%) and mixed (44% vs 30%) lesions were observed as compared to patients with SAP. In contrast, patients with SAP showed significantly more calcified (53% vs. 33%) plaques (p < 0.0001). Multivariate linear regression showed significant correlation between UAP and number of diseased segments (p = 0.001), number of segments with non-obstructive (p = 0.004), non-calcified (p = 0.006) and mixed (p = 0.0004) plaques.
Conclusions: Patients with UAP showed significantly more non-calcified and mixed plaques as compared to SAP patients. In addition, both obstructive and non-obstructive lesions were more frequently observed, indicating diffuse disease rather than focal atherosclerosis in patients with UAP. Based on assessment of plaque constitution and extent, MSCT may potentially identify patients at elevated risk for coronary events.