Overview

This trial is active, not recruiting.

Conditions autonomic nervous system diseases, orthostatic hypotension, dopamine beta-hydroxylase deficiency, orthostatic intolerance
Treatments standing or upright tilt, microneurography, qsweat, neck cuff stimulation, phenylephrine,isoproterenol,nitroprusside,propranolol,edrophonium,atropine,tyramine, clonidine,yohimbine,metoclopramide,alpha-methyldopa, bodpod, eye exam, sleep study, pain response testing, metabolic chamber, brain function studies, bicycle exercise test
Sponsor Vanderbilt University
Start date December 1996
End date December 2015
Trial size 25 participants
Trial identifier NCT00748059, 030752, HL056693

Summary

The purpose of this study is to determine the cause of low blood pressure in selective patients who have problems with their involuntary (autonomic) nervous system. These patients frequently have had symptoms throughout their life, and their disorder might have a genetic basis. The biochemical, physiological and pharmacological procedures in this study should help us define the problem and perhaps lead to more effective treatment.

United States No locations recruiting
Other Countries No locations recruiting

Study Design

Allocation non-randomized
Intervention model parallel assignment
Masking single blind (subject)
Primary purpose screening
Arm
(Experimental)
Patients with Orthostatic Hypotension
standing or upright tilt
stand upright or tilt table test
microneurography
Recording from sympathetic nerve
qsweat
quantitative sweat testing
neck cuff stimulation
Blood pressure receptors in the neck arteries may be stimulated by applying suction through a collar around the neck.
phenylephrine,isoproterenol,nitroprusside,propranolol,edrophonium,atropine,tyramine
IV Pharmacological Testing phenylephrine 12.5 - 400 ug, isoproterenol 0.1 - 0.4 ug or higher until desired effect, nitroprusside 0.1 - 1.6 ug/kg, propranolol 1.1 mg/min, edrophonium maximum of 10 mg, atropine .01 mg/kg, tyramine 250-4000 ug or higher until desired effect
clonidine,yohimbine,metoclopramide,alpha-methyldopa
Oral Pharmacological Testing clonidine 0.1-0.3 mg, yohimbine 5-10 mg, metoclopramide 10 mg, alpha-methyldopa 62.5 mg, placebo
bodpod
Determination of body composition
eye exam
Examination of pressure in the eye and eyelid fatiguability. The following eyedrops might be used: 0.5% proparacaine (Alcaine, Allergan, Inc) Fluress (0.4% benoxinate hydrochloride, fluorescein sodium, Akorn, Inc) 0.5%, 1% tropicamide (Mydriacyl, Alcon) Over-the-counter preservative-free artificial tears 0.25%, 2.5% and 10% phenylephrine (Bausch and Lomb) 1% cyclopentolate hydrochloride (Alcon)
sleep study
Recording of sleep pattern overnight
pain response testing
Subjects will rate the quality and intensity of 2 pain tasks.
metabolic chamber
Determination of metabolic rate via 24hr stay in whole-room indirect calorimeter
brain function studies
Questionnaires and computer tasks, an EEG and an MRI may be used to assess brain function.
bicycle exercise test
Blood pressure and heart rate may be monitored while exercising on a stationary bicycle.

Primary Outcomes

Measure
hemodynamic changes with standing
time frame: following test

Secondary Outcomes

Measure
blood and urine hormones
time frame: after test
blood volume
time frame: during supine and/or upright postures
sympathetic nerve activity
time frame: during stimulation of sympathetic nervous system
quantitative sweat testing
time frame: 2 hours
Eye function
time frame: once
Sleep efficiency
time frame: once
Metabolic rate
time frame: once
Pain response
time frame: once
Responses on questionnaires and computer tasks designed to assess brain function
time frame: once

Eligibility Criteria

Male or female participants from 12 years up to 70 years old.

Inclusion Criteria: - severe orthostatic hypotension and other autonomic symptoms but do not meet criteria for standard diagnosis - non-smokers - drug-free - able to give informed consent - free of pulmonary, renal, hematopoietic, hepatic and cardiac disease Exclusion Criteria: - medications affecting the autonomic nervous system - any chronic illness - anemia (Hct<30) - women of childbearing age who are pregnant or nursing - smokers

Additional Information

Official title The Pathophysiology of Orthostatic Hypotension
Principal investigator David Robertson, MD
Trial information was received from ClinicalTrials.gov and was last updated in June 2015.
Information provided to ClinicalTrials.gov by Vanderbilt University.