Prevention of Low Blood Pressure in Persons With Tetraplegia

April 23, 2014 updated by: US Department of Veterans Affairs
The aim of this investigation is to determine the blood pressure response to NOS inhibition, with L-NAME, in persons with tetraplegia compared to non-SCI control subjects and to establish if blood pressure can be increased while upright in those with tetraplegia. If blood pressure is increased with NOS inhibition in persons with tetraplegia, this would improve our treatment of the condition of low blood pressure during seated postures in individuals with tetraplegia.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Despite disruption of central command of the vasculature during orthostatic maneuvers, individuals with tetraplegia are generally able to be seated in an upright position for long periods of time without developing symptoms of orthostatic intolerance. It must be appreciated however, that orthostatic hypotension may occur unpredictably in persons with chronic tetraplegia. This may result in a range of symptoms due to cerebral hypoperfusion from mild reduction in mental acuity to loss of consciousness. Nitric oxide (NO) is the most potent endogenous vasodilator which is synthesized by the enzyme NO synthase (NOS) and may be largely responsible for orthostatic hypotension in individuals with immobilizing conditions. Recent evidence suggests an up-regulation of inducible nitric oxide synthases (NOS) activity with prolonged exposure to hind limb suspension. The effects of NOS inhibition during orthostasis on blood pressure regulation in those with chronic tetraplegia may provide insight into effective pharmacological therapy to reduce or prevent pathologic orthostatic changes. Treatment with a NOS inhibitor may facilitate the process of mobilization in those with acute higher cord lesions.

Study Type

Interventional

Enrollment (Actual)

16

Phase

  • Phase 2
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New York
      • Bronx, New York, United States, 10468
        • VA Medical Center, Bronx

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • 18 to 65 year olds.
  • Non-ambulatory Chronic tetraplegia (1 year after acute SCI).

Exclusion Criteria:

  • central nervous system disease (other than SCI) e.g., multiple sclerosis, amyotrophic lateral sclerosis, syringomyelia, tabes dorsalis;
  • peripheral neuropathies;
  • surgical sympathectomy;
  • coronary heart and/or artery disease;
  • anemia;
  • hypertension;
  • renal function abnormalities;
  • diabetes mellitus;
  • pituitary insufficiency;
  • adrenal insufficiency;
  • hypothyroidism; and
  • medications known to affect the cardiovascular system.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Arm 1
Placebo control (normal saline) is employed on a separate visit during procedure.
Drug: N-Nitro L-arginine-methylester (L-NAME)
A non-specific inhibitor of the nitric oxide synthase enzyme.
Procedure: Head-up Tilt maneuver
Participant will be placed onto tilt table and brought to 15 degrees of head up tilt for 60 minutes (intravenous infusion time). After this time, a progressive increase to 45 degrees will be completed with a 10 degree increase every 5 minutes. Participant will remain at 45 degrees for 45 minutes or until symptom onset.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Systolic Blood Pressure During Head-up Tilt
Time Frame: Average systolic blood pressure during head-up tilt (45 degrees) comparing active drug (L-NAME: 1.0 and 2.0 mg/kg) to placebo.
Average systolic blood pressure over 45 minutes at 45 degrees of head-up tilt.
Average systolic blood pressure during head-up tilt (45 degrees) comparing active drug (L-NAME: 1.0 and 2.0 mg/kg) to placebo.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

US Department of Veterans Affairs

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 2003

Primary Completion (Actual)

June 1, 2010

Study Completion (Actual)

June 1, 2010

Study Registration Dates

First Submitted

October 7, 2005

First Submitted That Met QC Criteria

October 11, 2005

First Posted (Estimate)

October 12, 2005

Study Record Updates

Last Update Posted (Estimate)

May 19, 2014

Last Update Submitted That Met QC Criteria

April 23, 2014

Last Verified

April 1, 2014

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • B3600-R

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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