Matrix Metalloproteinase 9 as a Predictor of Coronary Atherosclerotic Plaque Instability in Stable Coronary Heart Disease Patients with Elevated Lipoprotein(a) Levels

We sought to investigate whether levels of matrix metalloproteinases (MMPs) and their inhibitors predict coronary atherosclerotic plaque instability, as assessed by intravascular ultrasound (IVUS) virtual histology during coronary angiography. Blood samples were collected before angiography in 32 subjects (mean age 56 ± 8 years) with stable coronary heart disease (CHD) and elevated lipoprotein(a) (Lp(a), 94 ± 35 mg/dL). Levels of high-sensitivity C-reactive protein (hsCRP), apolipoprotein B100 (apoB100), MMP-7, MMP-9, tissue inhibitor of metalloproteinases (TIMP)-1, and TIMP-2 were determined using commercially available enzyme-linked immunosorbent assay kits. Results. The morphology of a total of sixty coronary lesions was assessed by virtual histology IVUS imaging. Eleven (18%) plaques in nine (28%) patients were classified as plaques with an unstable phenotype or a thin-cap fibroatheroma. Age, low-density lipoprotein cholesterol, apoB100, MMP-7, and MMP-9 levels were positively associated with necrotic core volume. Conversely, there was a negative relationship between MMP-7 and -9 levels and fibrous and fibro-fatty tissue volume. Multivariate regression analysis revealed that MMP-9 is a strong independent predictor of atherosclerotic plaque instability in stable CHD patients. In stable CHD patients with elevated Lp(a), MMP-9 levels are positively associated with the size of the necrotic core of coronary atherosclerotic plaques.

Relationships between coronary calcification detected at electron beam computed tomography and percutaneous transluminal coronary angioplasty results in coronary artery disease patients

Our objective was to assess the relationship between coronary artery calcification and outcomes of percutaneous transluminal coronary angioplasty (PTCA). Electron beam computed tomography (EBCT) was performed in 80 patients with coronary artery disease (CAD) who underwent PTCA. The calcium score in each coronary artery vessel was estimated (in Agatston units) and compared with the occurrence of complications and restenosis. Angioplasty had been performed in 96 coronary artery segments with stenosis in 80 patients. The average calcium score in the unsuccessful PTCA segments was significantly higher than in ones with successful results. For complications these values were 65.0+/-79.9 and 27.0+/-44.7, respectively ( p=0.02), and for restenosis 63.9+/-87.9 and 27.3+/-41.3, respectively ( p=0.03). Applying receiver operating characteristics analysis we determined sensitivity and specificity of EBCT for forecasting complications and restenosis. The best cut-off value of calcium score in segment of PTCA for prediction of restenosis was 27 (sensitivity 73%, specificity 67%), and for prediction of complications 29 (sensitivity 80%, specificity 74%). Coronary segments with extensive calcification were not optimal target lesions for PTCA. Analysis of coronary calcium score should be taken into consideration during planning of endovascular coronary interventions.