Relationship between multiple plasma biomarkers and vulnerable plaque determined by virtual histology intravascular ultrasound.

BACKGROUND The relationship between plasma biomarkers and vulnerable plaque is not well understood. METHODS AND RESULTS The 188 patients who underwent 3-vessel virtual histology (VH) intravascular ultrasound (IVUS) with peripheral blood sampling were enrolled. Plasma levels of matrix metalloproteinase 2 and 9 (MMP-2, -9), tissue inhibitor of metalloproteinase-1, adiponectin, and macrophage migration inhibitory factor were measured. VH-IVUS-derived thin cap fibroatheroma (VH-TCFA) was defined as a necrotic core >10% of plaque area in the presence of >40% plaque burden. There were 38 patients with ruptured plaque and 150 patients without (107 patients with VH-TCFA, 43 patients without VH-TCFA) in culprit/target lesions. Among the biomarkers, only the MMP-9 level was significantly higher in patients with ruptured plaque (P=0.002). In the subgroup without ruptured plaque, significant differences in the levels of several biomarkers were not observed between patients with and without VH-TCFA. In both culprit/target and nonculprit/non-target vessels, the MMP-9 level showed a weak correlation with the total number of ruptured plaques (r=0.231, P=0.002). CONCLUSIONS Among the biomarkers tested in this study, the MMP-9 level was significantly higher in patients with ruptured plaque. However, measurement of several biomarkers, including MMP-9, was incapable of predicting the presence of VH-TCFA.