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Racial Differences in the Coronary Microcirculation

Primary Purpose

Cardiovascular Diseases, Heart Diseases, Coronary Disease

Status
Completed
Phase
Locations
Study Type
Observational
Intervention
Sponsored by
National Heart, Lung, and Blood Institute (NHLBI)
About
Eligibility
Locations
Outcomes
Full info

About this trial

This is an observational trial for Cardiovascular Diseases

Eligibility Criteria

undefined - 100 Years (Child, Adult, Older Adult)MaleDoes not accept healthy volunteers

No eligibility criteria

Sites / Locations

    Outcomes

    Primary Outcome Measures

    Secondary Outcome Measures

    Full Information

    First Posted
    May 25, 2000
    Last Updated
    May 12, 2016
    Sponsor
    National Heart, Lung, and Blood Institute (NHLBI)
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    1. Study Identification

    Unique Protocol Identification Number
    NCT00005373
    Brief Title
    Racial Differences in the Coronary Microcirculation
    Study Type
    Observational

    2. Study Status

    Record Verification Date
    July 2000
    Overall Recruitment Status
    Completed
    Study Start Date
    September 1992 (undefined)
    Primary Completion Date
    undefined (undefined)
    Study Completion Date
    August 1998 (Actual)

    3. Sponsor/Collaborators

    Name of the Sponsor
    National Heart, Lung, and Blood Institute (NHLBI)

    4. Oversight

    5. Study Description

    Brief Summary
    To study mechanisms of excess coronary ischemia secondary to alterations in autoregulation and arteriolar vasoreactivity in Black Americans with hypertension, varying degree of left ventricular hypertrophy, and angiographically normal or mildly diseased coronary arteries.
    Detailed Description
    BACKGROUND: Although studies in 1992 with a sufficient number of minority patients were sparse, those available suggested that Black Americans had a higher case fatality from coronary heart disease, but lesser amounts of atherosclerotic coronary artery disease. A possible explanation for this apparent paradox was that myocardial ischemia might be more prevalent with less coronary artery atherosclerosis in Black Americans because of comorbid diseases or differences in coronary physiology. This could be secondary to excess hypertension and left ventricular hypertrophy in Black Americans but might also have been related to intrinsic or acquired differences in coronary artery autoregulation and vasoreactivity leading to depression in coronary blood flow and reserve. DESIGN NARRATIVE: The intracoronary Doppler flow velocity guidewire together with quantitative coronary angiography was used to study changes in coronary blood flow in blacks secondary to pharmacologic provocateurs known to induce arteriolar vasodilation. White Americans with similar demographic characteristics and equivalent amount of ventricular hypertrophy and coronary disease were similarly studied in a parallel fashion for comparison. A control group of normal white and Black Americans were studied to detect unexpected intrinsic differences. Both endothelium dependent and independent induction of coronary arteriolar vasodilation were studied. In 25 percent of patients with endothelium dependent defects in arteriolar vasodilation, retesting was performed after intracoronary infusion of L-arginine, the precursor of endothelium dependent relaxing factor. Finally, the possibility of a rightward shift in coronary artery autoregulation in chronic hypertension was investigated. This finding would necessitate that the lower limit of autoregulation occurred at higher diastolic pressures, resulting in a drop-off of coronary perfusion at normal physiologic pressures and ischemia. The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

    6. Conditions and Keywords

    Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
    Cardiovascular Diseases, Heart Diseases, Coronary Disease, Hypertension, Myocardial Ischemia, Hypertrophy, Left Ventricular

    7. Study Design

    10. Eligibility

    Sex
    Male
    Maximum Age & Unit of Time
    100 Years
    Accepts Healthy Volunteers
    No
    Eligibility Criteria
    No eligibility criteria

    12. IPD Sharing Statement

    Citations:
    PubMed Identifier
    9462582
    Citation
    Houghton JL, Davison CA, Kuhner PA, Torossov MT, Strogatz DS, Carr AA. Heterogeneous vasomotor responses of coronary conduit and resistance vessels in hypertension. J Am Coll Cardiol. 1998 Feb;31(2):374-82. doi: 10.1016/s0735-1097(97)00505-6.
    Results Reference
    background
    PubMed Identifier
    9217592
    Citation
    Houghton JL, Carr AA, Strogatz DS, Michel AI, Phillip JL, Kuhner PA, Smith VE, Breisblatt WM. Coronary vasomotor reactivity among normotensive African and white American subjects with chest pain. Am J Med. 1997 Mar;102(3):245-51. doi: 10.1016/S0002-9343(96)00449-4.
    Results Reference
    background
    PubMed Identifier
    9052885
    Citation
    Houghton JL, Smith VE, Strogatz DS, Henches NL, Breisblatt WM, Carr AA. Effect of African-American race and hypertensive left ventricular hypertrophy on coronary vascular reactivity and endothelial function. Hypertension. 1997 Mar;29(3):706-14. doi: 10.1161/01.hyp.29.3.706.
    Results Reference
    background
    PubMed Identifier
    6247382
    Citation
    Wood WD. Psychological soundness of women on psychiatry clerkship. J Am Med Womens Assoc (1972). 1980 May;35(5):128, 132. No abstract available.
    Results Reference
    background
    PubMed Identifier
    8144778
    Citation
    Houghton JL, Prisant LM, Carr AA, Flowers NC, Frank MJ. Racial differences in myocardial ischemia and coronary flow reserve in hypertension. J Am Coll Cardiol. 1994 Apr;23(5):1123-9. doi: 10.1016/0735-1097(94)90600-9.
    Results Reference
    background

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    Racial Differences in the Coronary Microcirculation

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