Randomized Trial of Imaging Versus Risk Factor-Based Therapy for Plaque Regression
Summary
Background:
- Atherosclerosis (thickening of the artery walls caused by cholesterol and other deposits) commonly occurs in the heart vessels and carotid (neck) arteries of adults. This is often present in individuals with high cholesterol levels in their blood. These patients are usually treated with cholesterol lowering medication ( statins ) along with modification of diet and exercise. Researchers are interested in investigating new approaches-including magnetic resonance imaging (MRI) and computed tomography (CT) imaging studies-to detect blood vessel blockages that would not otherwise be detected by cholesterol levels and risk factors for heart disease.
Objectives:
- To measure atherosclerosis in the heart vessels and carotid arteries using imaging tests (computed tomography (CT) and magnetic resonance imaging (MRI)) before and after standard treatment with cholesterol lowering medication ( statins )
Eligibility:
- Healthy individuals at least 55 years of age who are candidates for therapy to lower their blood cholesterol levels.
Design:
- This study will involve one screening visit and seven study visits over a period of 2 years.
- Participants will be screened with a physical examination and medical history, as well as blood samples and tests to ensure that it is safe for them to have CT and MRI scans. Participants will provide information on current medications, dietary habits, smoking status, alcohol and caffeine intake, and their level of physical activity.
- Participants will be divided into two groups. One group will receive standard doses of medication to lower cholesterol according to current treatment guidelines, while the other group will have MRI scans of the carotid arteries and a CT scan of the heart to determine the best medication dose levels.
- Visits 3 to 5 will be scheduled 3, 6, and 9 months after visit 2. During these visits, researchers will monitor for possible side effects and may change or adjust medications and doses.
- At visit 6, participants will have an MRI scan of the carotid arteries, a physical examination, and blood tests. Medications may be changed or adjusted.
- At visit 7, participants will have blood tests, and medications may be changed or adjusted.
- At the final visit, participants will have MRI and CT scans of the carotid arteries and heart, respectively, as well as a final physical examination and blood tests.
Description
The overall aim of this proposal is to compare the effectiveness of an image guided approach to lipid lowering to standard therapy guided by clinical risk factors and blood lipid levels. Men and women over age 55 who are candidates for statin therapy will be randomized to usual cholesterol lowering care, or to care guided by MRI images of the carotid arteries. Participants randomized to the second, imaging guided, group will be assigned to LDL cholesterol targets according to the degree of atherosclerosis seen by MRI. The study endpoints will be the total degree of plaque regression seen, the dosage of statin drugs required to achieve that reduction, and the rate of cardiovascular events.
FDG-PET is hypothesized to enable visualization of anti-inflammatory effects of statins that most likely occur before anatomic regression of the plaques can be demonstrated on MRI. A pilot substudy is to be conducted to explore this relationship. A subgroup of patients will be selected based on a moderate or high degree of atherosclerosis on carotid MRI and asked to participate in FDG PET imaging. The purpose of this pilot study is to determine if FDG avid lesions undergo a greater degree of morphologic regression with therapy controlling for the reduction in LDL cholesterol and the dosage of statins required to achieve that target.
Although contrast-enhanced coronary CT angiography (CTA) with multidetector computed tomography (MDCT) has been used extensively to characterize coronary artery plaque composition, there is little data regarding its reproducibility. A recent study demonstrated excellent reproducibility for this technique but this study was performed using the older 64 detector row CT scanners2. A pilot substudy will be conducted to study the reproducibility of coronary CT angiography using the newer generation of 320 detector row CT scanners.
Study Design
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind, Primary Purpose: Prevention
Conditions
Atherosclerosis
Intervention
LDL. Cholesterol (Statin Drugs), HMG-CoA Reductase Inhibitors
Location
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda
Maryland
United States
20892
Status
Recruiting
Source
National Institutes of Health Clinical Center (CC)
Results (where available)
Links
- Source: http://clinicaltrials.gov/show/NCT01212900
- Information obtained from ClinicalTrials.gov on May 28, 2013
Medical and Biotech [MESH] Definitions
Cholesterol Esters
Fatty acid esters of cholesterol which constitute about two-thirds of the cholesterol in the plasma. The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis.
Hydroxymethylglutaryl-coa Reductase Inhibitors
Compounds that inhibit HMG-CoA reductases. They have been shown to directly lower cholesterol synthesis.
5-alpha Reductase Inhibitors
Drugs that inhibit 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE. They are commonly used to reduce the production of DIHYDROTESTOSTERONE.
Cholesterol 7-alpha-hydroxylase
A membrane-bound cytochrome P450 enzyme that catalyzes the 7-alpha-hydroxylation of CHOLESTEROL in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP7, converts cholesterol to 7-alpha-hydroxycholesterol which is the first and rate-limiting step in the synthesis of BILE ACIDS.
Smith-lemli-opitz Syndrome
An autosomal recessive disorder of CHOLESTEROL metabolism. It is caused by a deficiency of 7-dehydrocholesterol reductase, the enzyme that converts 7-dehydrocholesterol to cholesterol, leading to an abnormally low plasma cholesterol. This syndrome is characterized by multiple CONGENITAL ABNORMALITIES, growth deficiency, and MENTAL RETARDATION.
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