Objective    To observe blood plasma matrix metalloproteinase-9 (MMP-9) of the patients with different types of carotid plaque and investigate the relationship between MMP-9 and carotid plaque vulnerability.     Methods    Totally 64 patients were examined by CDI

TCD

cranium CT

MRI

DSA and nerves function score (NIHSS) to judge their types of carotid plaque. Their plasma levels of MMP-9 and C-reactive protein (CRP) were detected.     Results    Plasma MMP-9 had direct correlation with plaque vulnerability(r=0.92，P0.01)

viz

the higher blood plasma MMP-9 level

the more vulnerable of the plaque was. Plasma CRP in carotid plaque group was significantly higher than those in health individuals

and those of patients with vulnerable and to-be-vulnerable plaque were higher than those of patients with non-vulnerable plaque (P0.01)

but there was no statistically significant between the former 2 groups.     Conclusion    There is a direct correlation of plasma MMP-9 with carotid plaque vulnerability. Carotid plaque vulnerability can be decided by imageology

clinical examination as well as plasma MMP-9 level. MMP-9 can be regarded as latent serum marker of vulnerable plaque

and has clinical significance in synteresis

diagnosis

and therapy of ischemic cerebrovascular disease.