IVUS elastography: a potential identifier of vulnerable atherosclerotic plaque

Rupture of atherosclerotic plaques is associated with acute myocardial infarction and unstable angina pectoris. Previously, plaque rupture has been associated with morphological features. In this study, the potential of intravascular elastography to detect stress concentrations that may indicate plaque vulnerability is investigated. Intravascular echograms and elastograms of excised human femoral arteries were determined using a custom made set-up. Next, sections were stained with picrosirius red and alpha-actin to counterstain collagen and smooth muscle cells (SMC), respectively. Human macrophage antibody staining was performed using anti-CD68 antibodies. Initial results of these experiments show that the strain in fatty tissue is higher than the strain in fibrous material. Furthermore, a plaque with all markers for plaque vulnerability revealed high strain levels at the vulnerable region within the plaque near the luminal border. These preliminary in vitro experiments indicate the potential of intravascular elastography to characterise different plaque components and to identify stress concentrations, one of the main indicators of plaque vulnerability. Additional validation studies will be required to evaluate the sensitivity and specificity of this technique.