Contribution of Angiotensin II to Supine Hypertension in Autonomic Failure

• Status: Terminated
• Trial end date: 2017-03-01
• Target enrollment: 0
• Participant gender: All

Summary

The purpose of this study is to test the hypothesis that angiotensin II plays a role in the supine hypertension of primary autonomic failure. To determine the contribution of angiotensin II to renin and blood pressure regulation in autonomic failure, patients with multiple system atrophy [MSA] or pure autonomic failure [PAF] and supine hypertension will undergo medication testing with the angiotensin II receptor blocker losartan. The investigators will compare the biochemical and hemodynamic effects between MSA and PAF patients. In a subset of patients, the investigators will also give the ACE inhibitor captopril. Our primary endpoint will be changes in plasma renin activity, and subsequent components of the circulating renin-angiotensin system, in response to angiotensin II blockade. Our secondary outcome will be changes in hemodynamic measures during administration of these drugs.

• Phase: Phase 1
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Vanderbilt University
• Treatments: Angiotensin II; Angiotensinogen; Captopril; Losartan

Criteria

Inclusion Criteria:

• Patients with autonomic failure who exhibit supine hypertension and are in the hospital already participating in the study "The Evaluation and Treatment of Autonomic Failure [IRB # 000814]

• Supine hypertension, defined as systolic blood pressure > 150 mm Hg and/or diastolic blood pressure > 90 mm Hg

• Males and females of all races, between 18 to 85 years of age

• Able and willing to provide informed consent with the understanding that they may withdraw consent at any time without prejudice to future medical care

Exclusion Criteria:

• All medical students

• Pregnant women

• Patients with a history of angioedema

• Patients with a known allergy to any ACE inhibitor or angiotensin receptor blocker

• High-risk patients [e.g. heart failure, symptomatic coronary artery disease, liver impairment, history of stroke or myocardial infarction]

• Patients with hemoglobin < 10.5 [or hematocrit < 32]

• Inability to give, or withdraw, informed consent

• Other factors which in the investigator's opinion would prevent the patient from completing the protocol including clinically significant abnormalities in clinical, mental or laboratory testing