Angioscopic assessment of vulnerable plaque and therapeutic application—lessons from acute coronary syndrome

Abstract

Angioscopic observation revealed occlusive, large amounts of white or mixed thrombus surrounding the ruptured, extensive yellow plaque (YP) or YP with ulceration in most culprit lesions of patients with acute coronary syndrome (ACS), and suggested that YP are vulnerable plaques. These YP were observed at angiographically normal lesions and were graded as grade 0 (white), grade 1 (slight yellow), grade 2 (yellow) and grade 3 (extensive yellow). The thinner the fibrous cap becomes, the brighter the color of YP becomes. This hypothesis is confirmed by the significant, high incidence of thrombus and the positive remodeling determined by the intravascular ultrasound at grade 3 YP. Thus, the angioscopically extensive YP is defined as a clinically unstable plaque. The prevalence of YP is high in the patients with ACS compared with those with other ischemic heart disease, and high-graded YP were frequently observed not only in the infarct-related artery but also non-infarct-related artery without the angiographic stenosis in patients with ACS. These results suggest that ACS represents the pan-coronary process of vulnerable plaque development. It has been recommended that more strict and careful management is necessary for the secondary prevention of ACS, rather than the primary prevention.