Carotid plaque composition by MRI during lipid-lowering

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DESCRIPTION (provided by applicant): This is a revised application of continuation of R01HL63895 entitled CAROTID PLAQUE COMPOSITION BY MRI DURING LIPID-LOWERING, which is a randomized, double blind, and partial placebo controlled study. In this study, 123 patients with CAD or carotid disease and with apolipoprotein B greater to or equal to 120 mg/dl (LDL levels 100-190 mg/dl) were randomized to one of three treatment groups: (1) single therapy - atorvastatin alone, placebos for niaspan and colesevelam; (2) double therapy - atorvastatin plus niaspan (2 g/day), and placebo for colesevelam; (3) triple therapy - atorvastatin, niaspan plus colesevelam (3.8 g/day). The treatment target for LDL is less than or equal to 80 mg/dl for the single and double therapy and less than or equal to 60 mg/dl for the triple therapy. The HDL target for the two niacin-treated groups is to increase 10 mg/dl from baseline. The patient recruitment is completed, and patient clinical/laboratory follow-up is on-going. All patients are undergoing MRI examination of both carotid arteries annually for three years, a total of 4 examinations. This proposed research is the first study to examine plaque lipid depletion, volume reduction, enhancement decrease by contrast-enhanced MRI in vivo during intensive lipid modification among patients with carotid atherosclerosis. The hypotheses and specific aims of the original grant plus this proposed continuation are: (1) to test the hypothesis that intensive lipid-lowering therapy decreases carotid plaque lipid content assessed by contrast-enhanced MRI. (2) To test the secondary and exploratory hypotheses that intensive lipid therapy is associated with plaque regression and decreased plaque enhancement assessed by contrast-enhanced MRI. (3) To examine the association of clinical risk factors, lipids, lipoprotein heterogeneity, inflammatory markers, oxidative stress markers with carotid plaque characteristics. (4) To investigate the effects of HDL-raising and very intensive LDL-lowering, comparing to LDL-lowering alone, on carotid lipid content, volume, and enhancement over 3 years. (5) To determine if carotid plaque characteristics (lipid content, volume, and enhancement) or its change predicts future major cardiovascular events. The primary MRI endpoint is carotid plaque lipid content. The secondary endpoints are plaque volume, other tissue contents. The exploratory endpoint is plaque enhancement assessed by contrast- enhanced MRI. This study employs a state-of-the art technique to examine the effects of lipid-lowering therapy on human atherosclerotic plaque characteristics in vivo and will provide novel insights into our understanding of atherosclerotic plaque pathology and the mechanisms of intensive lipid modification in preventing ischemic events.