Abstract： The atherosclerotic plaque vulnerability may be related to inflammation,immunity,metabolism and blood clotting.One of the key factors affecting plaque stability is inflammatory reaction.This study was to investigate the relationship between vulnerability of coronary artery plaque evaluated with coronary angiography (CAG),intravascular ultrasound (IVUS) and the levels of plasma inflammatory markers.Methods Fifty-eight consecutive patients with acute coronary syndrome who had coronary lesion of a single vessel were divided into 3 groups based on angiographic morphology of the lesions:type Ⅰ lesion group (n =16),type Ⅱ lesion group (n =25) and type Ⅲ lesion group (n =17).The control group consisted of 17 patients with stable angina.Plasma levels of high sensitivity C reaction protein (hs-CRP),matrix metalloproteinase (MMP,including MMP-2 and MMP-9),CD40 ligand (CD40L) and pregnancy associated plasma protein-A (PAPP-A) were measured by ELISA.A subgroup of 28 patients (including 18 ACS patients and 10 stable angina control patients) who underwent IVUS study,were analyzed.Results The plasma levels of MMP-2,MMP-9 and PAPP-A in type Ⅱ lesion group were significantly higher than those in other groups (all P＜0.05).In type Ⅱ lesion group,linear correlation analyses showed significant positive correlation between levels of hs-CRP and MMP-2 (r=0.508);MMP-2 and MMP-9,CD40L,PAPP-A (r=0.647,0.704 and 0.751,respectively);MMP-9 and CD40L,PAPP-A (r=0.491 and 0.639,respectively);CD40L and PAPP-A (r=0.896).IVUS subgroup analysis showed that the area of plaques and plaque burden in culprit lesion,the incidence of high-risk plaques,remodeling index (RI) and positive remodeling percentage in ACS patients were significantly greater than those in control subgroup (P=0.000,0.037,0.028,0.015 and 0.040,respectively).Compared with control subgroup,the plasma levels of hs-CRP,MMP-2,MMP-9 and PAPP-A were markedly elevated (P=0.033,0.000,0.000 and 0.027,respectively).Conclusions CAG and IVUS combined with study on plasma levels of inflammation mediators are helpful in judging the vulnerability of coronary artery plaques.(J Geriatr Cardiol 2008;5:207-211)