Visualization of Plaque Neovascularization by OCT

Abstract

Although the introduction of drug-eluting-stents (DES) has dramatically reduced restenosis and the need for repeat revascularization compared with bare-metal stents (BMS), percutane‐ ous coronary intervention (PCI) does not always prevent cardiac events, including acute coro‐ nary syndrome (ACS) [1]. Therefore, for all cardiologists, the detection of vulnerable plaques before they rupture is one of ultimate goals to predict and prevent ACS. Vulnerable plaques are characterized as thin fibrous cap (<65 μm), large lipid core, and macrophage infiltration within the cap. Furthermore, plaque neovascularization has been identified recently as a common fea‐ ture of plaque vulnerability. Increased neovascularization in atherosclerotic plaques plays an important role in plaque progression, plaque instability, and rupture of plaque [2-5]. Until re‐ cently, however, in vivo studies assessing neovascularization in atherosclerotic plaques have been difficult because of the lack of sufficient resolution that reliably identifies this feature of vulnerable plaque. The first-generation catheter-based Time-domain optical coherence tomog‐ raphy (TD-OCT) system (M2 and M3 OCT system; LightLab Imaging, Westford, MA, USA), which offers superior resolution of 10-15 μm, has emerged as an intracoronary imaging modal‐ ity, rendering the detailed micro-structure information of coronary plaques [6-8]. With its ex‐ cellent resolution, OCT may provide an opportunity to directly detect plaque neovascularization in vivo. This chapter reviews the evidence of plaque neovascularization ac‐ cumulated so far on OCT and discuss the future perspectives and limitations.