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Long-Term Effects of Subclinical CAD on Cardiac Function

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00006497
Recruitment Status : Completed
First Posted : November 17, 2000
Last Update Posted : August 21, 2008
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To assess changes in coronary calcium measured by electron beam computed tomography (EBCT) as a predictor of coronary heart disease (CHD) events.

Condition or disease
Cardiovascular Diseases Coronary Arteriosclerosis Coronary Disease Heart Diseases

Detailed Description:


Despite extensive research over many years, noninvasive methods for detection of the presence and severity of coronary artery disease remain imperfect, in part due to the fact that different, partially interrelated, facets of coronary atherosclerosis may predispose to different manifestations (e.g., luminal diameter narrowing to myocardial ischemia and wall plaque burden to a higher risk or acute thrombosis). One noninvasive index of the degree of coronary atherosclerosis, the extent of coronary artery calcification, has become more accessible to non-invasive evaluation due to the development of fast electron-beam computed tomography (EBCT). Initial studies have shown that EBCT coronary calcification is related to a variety of coronary risk factors and is also predictive to a variable extent in different populations of incident coronary heart disease events, but few data are available concerning the evolution of EBCT-detected coronary calcification and its relation to coronary risk factors or to prevalent or incident coronary heart disease.

The study draws on the success of the Los Angeles South Bay Heart Watch (SBHW) in recruiting an ethnically-diverse sample of individuals at high risk of coronary heart disease events who have undergone serial evaluation by both assessment of conventional coronary heart disease risk factors and by evaluation of coronary arterial calcification by fluoroscopy and by EBCT on sequential evaluations. The study group has been able to maintain contact with the participants and achieve outstanding rates of both contact for follow-up and repeat participation in sequential components of the study.


The study follows up 1,000 asymptomatic high-risk survivors from the South Bay Heart Watch population recruited in 1990-1992 (n = 1,461) and studied with EBCT in 1992-1993 (n = 1,309). The primary objective is to examine the effects of baseline risk factors and measures of calcium metabolism on changes in the amount of coronary calcium in this asymptomatic high-risk adult cohort. This observational study has the following specific aims, as follow: 1) relating demographic factors and traditional risk factors to progression in coronary artery calcification (CAC) score over time; 2) relating serum markers of calcium metabolism to changes in CAC score; and 3) relating baseline CAC score and changes in CAC score to left ventricular dysfunction and intervening coronary events.

The SBHW cohort and NHLBI reading center as well as Dr. Azen's data coordinating center are used to examine whether baseline risk factors, ethnic group and indices of calcium metabolism are associated with change in coronary calcium quantity over four to five years. EBCT scans are performed in 1,000 surviving members of the cohort as are repeat measurements of left ventricular hypertrophy, plasma lipids, blood pressure, homocysteine, fibrinogen, para-thyroid hormone and vitamin D levels. The independent relationships between risk factors are examined from the 1994 baseline evaluation and the change in coronary calcium score as determined by EBCT. Logistic regression, which is not dependent on normality of the independent variables, will be used to examine the relation of annualized change in coronary calcium with the incidence of events. The study continues through August, 2008.

Study Type : Observational
Study Start Date : September 2000
Primary Completion Date : August 2008
Study Completion Date : August 2008

Information from the National Library of Medicine

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Ages Eligible for Study:   48 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
No eligibility criteria

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00006497

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Robert Detrano Harbor-UCLA Research & Education Institute