The Pathophysiology of Orthostatic Hypotension

Orthostatic Hypotension Clinical Trial

Official title:

The Pathophysiology of Orthostatic Hypotension

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00748059
• Other study ID #: 030752
• Secondary ID: HL056693
• Status: Completed
• Phase: Phase 1
• Start date: December 1996
• Est. completion date: December 2020

Study information

• Verified date: May 2021
• Source: Vanderbilt University Medical Center
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 10
• Est. completion date: December 2020
• Est. primary completion date: December 2020
• Accepts healthy volunteers: No
• Gender: All
• Age group: 12 Years to 70 Years

Eligibility

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

Related Conditions & MeSH terms

• Autonomic Nervous System Diseases
• Dopamine Beta-Hydroxylase Deficiency
• Hypotension
• Hypotension, Orthostatic
• Nervous System Diseases
• Orthostatic Hypotension
• Orthostatic Intolerance
• Primary Dysautonomias

Intervention

Procedure:
• Standing or upright tilt
stand upright or tilt table test
• Microneurography
Recording from sympathetic nerve
• QSweat
quantitative sweat testing

Device:
• neck cuff stimulation
Blood pressure receptors in the neck arteries may be stimulated by applying suction through a collar around the neck.

Drug:
• 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

Procedure:
• 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.

Locations

Country	Name	City	State
United States	Vanderbilt University	Nashville	Tennessee

Sponsors (1)

Lead Sponsor	Collaborator
Vanderbilt University Medical Center

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	hemodynamic changes with standing		following test
Secondary	blood and urine hormones		after test
Secondary	blood volume		during supine and/or upright postures
Secondary	sympathetic nerve activity		during stimulation of sympathetic nervous system
Secondary	quantitative sweat testing		2 hours
Secondary	Eye function		once
Secondary	Sleep efficiency		once
Secondary	Metabolic rate		once
Secondary	Pain response		once
Secondary	Responses on questionnaires and computer tasks designed to assess brain function		once

External Links

•   Autonomic Dysfunction Center Website