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Racial Differences in Control of Blood Vessel Tone and Blood Flow

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00001747
First Posted: December 10, 2002
Last Update Posted: March 4, 2008
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.
Information provided by:
National Institutes of Health Clinical Center (CC)
  Purpose

Black Americans tend to die more often from and have more diseases associated with heart disease than White Americans. The exact cause of this is unknown, but it is likely a combination of genetics, behavior, risk factors, strategies for education and prevention, and socioeconomic factors.

Recent studies have suggested that faster biological processes in blood vessels of Black Americans may be the cause of increased amounts of heart disease. In addition, small blood vessels in Black Americans seem to be less responsive to substances that relax blood vessels, which may explain increased blood pressure levels.

In this study researchers plan to study artery relaxation (dilation) in response substances affecting the cells lining blood vessels (endothelin). Researchers will compare the results of this study in black and white people to find out whether racial differences may contribute to increases in heart disease and heart related deaths in blacks.


Condition
Atherosclerosis Healthy Hypertension

Study Type: Observational
Official Title: Racial Differences in Flow Mediated Vasodilator Function

Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 108
Study Start Date: May 1998
Estimated Study Completion Date: March 2001
Detailed Description:
Black Americans have a greater morbidity and mortality related to cardiovascular diseases compared to whites. The cause for this phenomenon is probably multifactorial and includes differences in pathogenesis, risk factor patterns, genetic background, behavioral variables, strategies for education and prevention, and socioeconomic factors. Recent evidence suggests that acceleration of some of the processes related to vascular biology may account for the greater prevalence of cardiovascular disease in blacks. A diminished vasodilator response of the microvasculature has been shown in African Americans and may therefore be responsible for their increased prevalence of hypertension. Endothelial dysfunction is a central mechanism in the development of atherosclerosis. It is therefore reasonable to postulate that endothelial dysfunction of large conductance arteries may also contribute to a greater susceptibility to atherosclerosis in blacks compared to whites, even in those individuals without the known risk factors for coronary heart disease. In the present study, we propose to investigate brachial artery dilation in response to endothelium-dependent and -independent stimuli in black and white individuals to determine whether racial differences in the vascular biology of large conductance vessels that might contribute to the greater cardiovascular morbidity and mortality previously reported in blacks.
  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Black and white normal volunteers, approximately matched for age and sex, will be included in the study.

All subjects must be capable of rendering informed consent for all procedures.

Volunteers with a history or evidence of present or past hypertension (BP greater than 140/90), diabetes mellitus, hypercholesterolemia (plasma cholesterol greater than 200 mg/dL), cardiac disease, peripheral vascular disease, coagulopathy, chronic smoking (2 pack-years or more), obesity (20% greater than ideal body weight), hyperhomocysteinemia (plasma homocysteine greater than 17 umol/1) or any other disease predisposing them to vasculitis will be excluded from the study.

No pregnant women.

Volunteers who are taking any medication will be excluded.

  Contacts and Locations
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 ClinicalTrials.gov identifier (NCT number): NCT00001747


Locations
United States, Maryland
National Heart, Lung and Blood Institute (NHLBI)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
  More Information

Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
ClinicalTrials.gov Identifier: NCT00001747     History of Changes
Other Study ID Numbers: 980112
98-H-0112
First Submitted: November 3, 1999
First Posted: December 10, 2002
Last Update Posted: March 4, 2008
Last Verified: May 2000

Keywords provided by National Institutes of Health Clinical Center (CC):
Brachial Artery
Doppler
Endothelium
Nitric Oxide
Nitroglycerin
Normal Volunteer

Additional relevant MeSH terms:
Atherosclerosis
Arteriosclerosis
Arterial Occlusive Diseases
Vascular Diseases
Cardiovascular Diseases