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: May 21, 2014
Last verified: May 2014
  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:
  • Systolic Blood Pressure [ Time Frame: acute testing ] [ Designated as safety issue: No ]
    Systolic blood pressure during head-up tilt in subjects with spinal cord injury without drug intervention


Secondary Outcome Measures:
  • Cerebral Blood Flow [ Time Frame: acute testing ] [ Designated as safety issue: No ]
    Measurement of middle cerebral artery blood flow velocity supine and during head-up tilt


Enrollment: 30
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
Placebo Comparator: ARM 1
Head-up tilt maneuver without drug in subjects with spinal cord injury
Other: Head up tilt (HUT)
45 degree head-up tilt to lower blood pressure and measure cerebral blood flow.
Placebo Comparator: ARM 3
Head-up tilt maneuver without drug in able-bodied controls
Other: Head up tilt (HUT)
45 degree head-up tilt to lower blood pressure and measure cerebral blood flow.
Active Comparator: ARM 2
Head-up tilt maneuver with an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat) in subjects with spinal cord injury
Drug: 1.25 mg enalaprilat IV
an angiotensin converting enzyme (ACE) inhibitor given to lower blood pressure (BP) and measure cerebral blood flow (CBF)
Other: Head up tilt (HUT)
45 degree head-up tilt to lower blood pressure and measure cerebral blood flow.
Active Comparator: ARM 4
Head-up tilt maneuver with an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat) in able-bodied controls.
Drug: 1.25 mg enalaprilat IV
an angiotensin converting enzyme (ACE) inhibitor given to lower blood pressure (BP) and measure cerebral blood flow (CBF)
Other: Head up tilt (HUT)
45 degree head-up tilt to lower blood pressure and measure cerebral blood flow.

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
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

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
Results First Received: September 12, 2013
Last Updated: May 21, 2014
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
Autonomic Nervous System Diseases
Cardiovascular Diseases
Central Nervous System Diseases
Nervous System Diseases
Orthostatic Intolerance
Primary Dysautonomias
Spinal Cord Diseases
Trauma, Nervous System
Vascular Diseases
Wounds and Injuries
Angiotensin-Converting Enzyme Inhibitors
Enalapril
Enalaprilat
Antihypertensive Agents
Cardiovascular Agents
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Pharmacologic Actions
Protease Inhibitors
Therapeutic Uses

ClinicalTrials.gov processed this record on October 21, 2014