Racial Differences in the Coronary Microcirculation
Primary Purpose
Cardiovascular Diseases, Heart Diseases, Coronary Disease
Status
Completed
Phase
Locations
Study Type
Observational
Intervention
Sponsored by
About this trial
This is an observational trial for Cardiovascular Diseases
Eligibility Criteria
No eligibility criteria
Sites / Locations
Outcomes
Primary Outcome Measures
Secondary Outcome Measures
Full Information
NCT ID
NCT00005373
First Posted
May 25, 2000
Last Updated
May 12, 2016
Sponsor
National Heart, Lung, and Blood Institute (NHLBI)
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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