The Role of Angiotensin Type I Receptor in the Regulation of Human Coronary Vascular Function

NCT ID: NCT00001629

Last Updated: 2008-03-04

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE3

Total Enrollment

49 participants

Study Classification

INTERVENTIONAL

Study Start Date

1997-07-31

Study Completion Date

2000-09-30

Brief Summary

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The renin angiotensin system (RAS) plays an important physiological and pathophysiological role in the control of blood pressure and plasma volume. Inhibition of the RAS is useful in the treatment of hypertension, cardiac failure and in some patients with myocardial infarction. Several recent clinical trials with angiotensin converting enzyme inhibitors (ACEI) have shown that they also reduce the incidence of myocardial infarction, but the mechanisms underlying this anti-ischemic effect are poorly understood. ACEI reduce angiotensin II synthesis and prevent bradykinin degradation. Results from ongoing studies in the Cardiology Branch (Protocol 95-H-0099) designed to investigate the link between ACEI and the vascular endothelium indicate that ACEI improve both endothelial dysfunction and metabolic coronary vasodilation, an effect that is partially mediated by bradykinin. The current protocol is designed to investigate whether the beneficial effects of ACEI on endothelial function are also partly due to inhibition of angiotensin II. The recent development of selective angiotensin II type 1 (AT1) receptor antagonists allows us to specifically examine the effects of angiotensin II on vasomotor activity.

Detailed Description

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The renin angiotensin system (RAS) plays an important physiological and pathophysiological role in the control of blood pressure and plasma volume. Inhibition of the RAS is useful in the treatment of hypertension, cardiac failure and in some patients with myocardial infarction. Several recent clinical trials with angiotensin converting enzyme inhibitors (ACEI) have shown that they also reduce the incidence of myocardial infarction, but the mechanisms underlying this anti-ischemic effect are poorly understood. ACEI reduce angiotensin II synthesis and prevent bradykinin degradation. Results from ongoing studies in the Cardiology Branch (Protocol 95-H-0099) designed to investigate the link between ACEI and the vascular endothelium indicate that ACEI improve both endothelial dysfunction and metabolic coronary vasodilation, an effect that is partially mediated by bradykinin. The current protocol is designed to investigate whether the beneficial effects of ACEI on endothelial function are also partly due to inhibition of angiotensin II. The recent development of selective angiotensin II type 1 (AT1) receptor antagonists allows us to specifically examine the effects of angiotensin II on vasomotor activity.

Conditions

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Atherosclerosis Heart Failure, Congestive Hypertension Myocardial Infarction

Study Design

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Primary Study Purpose

TREATMENT

Interventions

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Angiotensin II type 1 receptor antagonists

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

Patients investigated for chest pain syndrome with normal coronary arteries with and without risk factors for atherosclerosis, patients with coronary artery disease, and patients with heart failure.

No patients with unstable angina; significant left main disease (greater than 50% stenosis); Recent myocardial infarction (less than 1 month); Pregnancy, lactation; Allergy to losartan; Renal failure (creatinine greater than 2.5 mg/dl); Inability to withdraw ACE inhibitors.
Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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National Heart, Lung, and Blood Institute (NHLBI)

NIH

Sponsor Role lead

Locations

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National Heart, Lung and Blood Institute (NHLBI)

Bethesda, Maryland, United States

Site Status

Countries

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United States

References

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Cockcroft JR, Sciberras DG, Goldberg MR, Ritter JM. Comparison of angiotensin-converting enzyme inhibition with angiotensin II receptor antagonism in the human forearm. J Cardiovasc Pharmacol. 1993 Oct;22(4):579-84. doi: 10.1097/00005344-199310000-00011.

Reference Type BACKGROUND
PMID: 7505360 (View on PubMed)

Goldberg MR, Tanaka W, Barchowsky A, Bradstreet TE, McCrea J, Lo MW, McWilliams EJ Jr, Bjornsson TD. Effects of losartan on blood pressure, plasma renin activity, and angiotensin II in volunteers. Hypertension. 1993 May;21(5):704-13. doi: 10.1161/01.hyp.21.5.704.

Reference Type BACKGROUND
PMID: 8491505 (View on PubMed)

Sudhir K, MacGregor JS, Gupta M, Barbant SD, Redberg R, Yock PG, Chatterjee K. Effect of selective angiotensin II receptor antagonism and angiotensin converting enzyme inhibition on the coronary vasculature in vivo. Intravascular two-dimensional and Doppler ultrasound studies. Circulation. 1993 Mar;87(3):931-8. doi: 10.1161/01.cir.87.3.931.

Reference Type BACKGROUND
PMID: 8383016 (View on PubMed)

Other Identifiers

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97-H-0142

Identifier Type: -

Identifier Source: secondary_id

970142

Identifier Type: -

Identifier Source: org_study_id

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