Abstract 3209: Coronary Plaque Composition in Acute Coronary Syndromes and Stable Coronary Artery Disease; Systematic Evaluation with Multislice Computed Tomography and Virtual Histology Intravascular Ultrasound
Introduction: Plaque composition rather than degree of stenosis may be responsible for coronary events. In vivo coronary plaques may be noninvasively evaluated with multislice computed tomography (MSCT) and preliminary data suggest that less calcified plaques are present in the setting of acute coronary syndromes (ACS). Invasively, plaque composition may be evaluated with high spatial resolution by virtual histology intravascular ultrasound (VH IVUS) .Thus far no comparative data on plaque characterization by 2 techniques are available. We assessed hypothesis that differences in coronary plaque composition on MSCT are present in patients with ACS and stable coronary artery disease, which could be related to plaque features of high risk on VH IVUS.
Methods: In total, 25 patients with ACS and 25 with stable coronary artery disease underwent 64-slice MSCT followed by invasive coronary angiography with VH IVUS. Three types of plaques on MSCT (noncalcified, mixed, calcified) and 4 tissue types on VH IVUS (fibrotic, fibro-fatty, necrotic core, dense calcium) together with the presence of thin cap fibroatheroma (plaque burden >40%, necrotic core >10%, no overlying fibrous cap) were evaluated.
Results: In total, 179 and 118 plaques on MSCT were observed in patients with ACS and with stable coronary artery disease. More noncalcified (57 (32%) vs 14 (12%)) and mixed plaques (105 (59%) vs 32 (27%)), whereas less calcified plaques (17 (9%) vs 72 (61%)) were observed in ACS as compared to patients with stable coronary artery disease (p<0.0001). In plaques where VH IVUS was performed (97 in ACS, 61 in stable coronary artery disease), more necrotic core was demonstrated in the setting of ACS (11.16%±6.07% vs 9.08%±4.62%, p=0.02). Thin cap fibroatheroma was identified in 31 (32%) plaques in ACS, whereas these features were present in only 2 (3%) plaques of patients with stable coronary artery disease (p<0.0001).
Conclusions: Differences in plaque characteristics were observed in patients with ACS and stable coronary artery disease on MSCT and VH IVUS. More noncalcified and mixed plaques on MSCT were observed in the setting of ACS. Plaques of patients with ACS were associated with high risk features on VH IVUS.