A Study of Blood Pressure and Blood Supply to the Brain in Persons With a Spinal Cord Injury.

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Department of Veterans Affairs
ClinicalTrials.gov Identifier:
NCT00248807
First received: November 2, 2005
Last updated: August 29, 2013
Last verified: August 2013
  Purpose

The purpose of this study is to determine how blood pressure and blood flow are controlled during head-up tilt in a semi-upright position. In this investigation we are studying blood pressure and blood flow to the brain, with and without a medication which lowers blood pressure (Vasotec). We will determine how persons with a spinal cord injury are able to maintain blood flow to the brain (not get dizzy) as they assume a more upright position and their blood pressure decreases.


Condition Intervention
Orthostatic Hypotension
Spinal Cord Injuries
Drug: 1.25 mg enalaprilat IV
Other: Head up tilt (HUT)

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Health Services Research
Official Title: Systemic Hemodynamics and Cerebral Blood Flow in Persons With Tetraplegia

Resource links provided by NLM:


Further study details as provided by Department of Veterans Affairs:

Primary Outcome Measures:
  • cerebral blood flow and blood pressure [ Time Frame: Cerebral blood flow and blood pressure will be measured every 20 and 10 minutes, respectively during the baseline and post-challenge periods. ] [ Designated as safety issue: No ]
    The speed of blood flow in the middle cerebral artery will be measured by transcranial doppler as an index of blood flow to the brain. Systemic blood pressure will be measured at the brachial artery. Cerebral blood flow and blood pressure will be measured before, during and after each intervention on each of the 3 visits.


Enrollment: 31
Study Start Date: October 2005
Study Completion Date: April 2012
Primary Completion Date: May 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Arm 1
1.25 mg enalaprilat IV and/or 45 degree HUT to lower BP and measure CBF
Drug: 1.25 mg enalaprilat IV
an ACE inhibitor given to lower BP and measure CBF
Other: Head up tilt (HUT)
45 degree HUT to lower BP and measure CBF

Detailed Description:

Individuals with tetraplegia lack normal sympathetic nervous system regulation of blood pressure and, therefore, relative hypotension is a common occurrence. This hypotension may be more pronounced with postural stress. Loss in mental acuity and sometimes even consciousness is an associated symptom of postural hypotension in individuals with tetraplegia.

There is some evidence to suggest that although mean arterial blood pressure (MAP) is relatively low in these individuals, middle cerebral arterial blood flow (CBF) may be maintained. Consequently, individuals with chronic tetraplegia often compensate and are stable in the seated upright position.

Autoregulation of CBF has been defined as the stability of cerebral blood flow throughout a range of systemic blood pressures (MAP). This proposal will examine systemic hemodynamics and middle cerebral artery blood flow during HUT with and without Vasotec, an angiotensin II inhibitor. By partially or completely ablating the renin-angiotensin system, which is postulated to play a major role in blood pressure regulation, the potential dissociation between systemic blood pressure and middle cerebral artery blood flow, in individuals with tetraplegia, may be demonstrated. The aim is to determine whether persons with chronic tetraplegia are able to maintain similar CBF, or similar CBF changes, as able-bodied controls despite a greater decrease in MAP to the same hypotensive challenge. The relationship between MAP and CBF has not been defined in this population. Understanding this relationship may lead to improved screening and treatment for prevention of postural hypotension in persons with tetraplegia.

  Eligibility

Ages Eligible for Study:   18 Years to 65 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Duration of spinal cord injury (SCI) at least 1 year
  • Level of SCI C4-8 and T6 and below
  • matched non-SCI subjects
  • Chronological age between 18-65 years
  • Euhydration: Subjects will be instructed to avoid caffeine and alcohol and to maintain normal salt and water intake for several days prior to study.

Exclusion Criteria:

  • Known heart and/or blood vessel disease
  • Dehydration
  • High blood pressure
  • Kidney disease
  • Diabetes mellitus
  • Prescribed ACE inhibitors
  • Acute Infection
  • Smoking
  • Pregnancy
  Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT00248807

Locations
United States, New York
VA Medical Center, Bronx
Bronx, New York, United States, 10468
Sponsors and Collaborators
Investigators
Principal Investigator: Jill Wecht, EdD VA Medical Center, Bronx
  More Information

Publications:
Responsible Party: Department of Veterans Affairs
ClinicalTrials.gov Identifier: NCT00248807     History of Changes
Other Study ID Numbers: B3346-V, 00517
Study First Received: November 2, 2005
Last Updated: August 29, 2013
Health Authority: United States: Federal Government

Keywords provided by Department of Veterans Affairs:
Blood Pressure, Low
Hypotension, Postural
Injuries, Spinal Cord
Spinal Cord Transection
Spinal Cord Trauma

Additional relevant MeSH terms:
Hypotension
Hypotension, Orthostatic
Spinal Cord Injuries
Wounds and Injuries
Vascular Diseases
Cardiovascular Diseases
Orthostatic Intolerance
Primary Dysautonomias
Autonomic Nervous System Diseases
Nervous System Diseases
Spinal Cord Diseases
Central Nervous System Diseases
Trauma, Nervous System
Enalaprilat
Enalapril
Antihypertensive Agents
Cardiovascular Agents
Therapeutic Uses
Pharmacologic Actions
Angiotensin-Converting Enzyme Inhibitors
Protease Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action

ClinicalTrials.gov processed this record on April 20, 2014