Nature Of Coronary Artery Plaque Evaluated By Optical Coherence Tomography And Its Correlations With MMP7, MMP9 And MMP12

Objective:After coronary angiography, optical coherence tomography (OCT) was applied to evaluate the nature of coronary artery plaque and its correlations with matrix metalloproteinase 7 (MMP7), MMP9 and MMP12.Methods:Patients who were confirmed with coronary artery lesions by coronary angiography in Department of Cardiology of the First Affiliated Hospital of Kunming Medical University from October 2014 to March 2016 and willing to receive OCT were recruited. Based on the results of coronary angiography and OCT, the patients were divided into control group (normal coronary angiography), stable plaque group and unstable plaque group for case-control study. The research objects’age, gender, height, weight, blood fat, histories of hypertension, diabetes and smoking as well as family history of coronary heart disease (CHD) are collected. ELISA was used to measure MMP7, MMP9 and MMP12 and CR-7OCT diagnostic apparatus (St. Jude Medical, Inc., USA) was applied to observe and determine the thickness of fibrous cap of plaque, angle of lipid pool, macrophage infiltration, plaque cracks, new vessels inside plaque, etc. Besides, SPSS 17.0 software was used to statistically analyze the observed data and the difference was considered to be statistically significant if p< 0.05.Results:1. The proportions of hypertension and diabetes patients, total cholesterol value and low density lipoprotein (LDL) value were all higher in the unstable and stable plaque groups than in the control group (p< 0.05); and the unstable plaque group was found with higher proportion of diabetes patients and creatine kinase isoenzyme compared with the stable plaque group (p< 0.05).2. MMP7 and MMP9 levels in the unstable plaque group were higher than that in the other two groups (p< 0.05).3. The fibrous cap was thicker in the stable plaque group than in the unstable plaque group (p< 0.01); and the unstable plaque group was superior to the stable plaque group in the angle of lipid pool, microphage infiltration, inner membrane erosion and plaque cracks (p< 0.05).4. The thickness of fibrous cap was found to be negatively correlated with MMP9 level (r=-0.336, p= 0.034); the group with microphage infiltration had higher MMP7 and MMP9 levels compared with the group without microphage infiltration (p< 0.05); MMP9 level in the group with inner membrane erosion was higher than that in the group without inner membrane erosion (p< 0.01).Conclusions:1.The existence of diabetes, hypertension and hypercholesterolemia, especially high density lipoprotein, is of great significance to predicting the occurrence and development degree of coronary plaque, which should be taken as a necessary check for diagnosing CHD population; while the history of diabetes is more likely to indicate unstable plaque.2.The combination of coronary angiography and OCT is able to analyze coronary plaque lesions in a qualitative and quantitative way and beneficial to making treatment decisions for further lesion optimization and performing coronary angiography on patients who are suspected of having CHD, which is worth promotion.3.MMP7 and MMP9 levels increase significantly in the patients with unstable plaque lesions, indicating that they can be considered as an important basis for determining whether coronary plaques are stable or not and guiding treatment.4.Thin plaque fibrous cap, big lipid pool, macrophage infiltration, inner membrane erosion and plaque cracks which are scanned by OCT can be taken as main characteristics of the unstable plaques. An increase in MMP9 suggests that plaque fibrous cap is getting thinner, macrophages are infiltrating and an erosion may occur in the inner membrane, which hint that acute coronary syndrome (ACS) is likely to have happened.