Skip to main content
OpenTrials
Completed

NCT Number: NCT00248807

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

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.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Orthostatic Hypotension Autonomic Nervous System Diseases Cardiovascular Diseases Central Nervous System Diseases Hypotension Hypotension, Orthostatic Nervous System Diseases Orthostatic Intolerance Primary Dysautonomias Spinal Cord Diseases Spinal Cord Injuries Trauma, Nervous System Vascular Diseases Wounds and Injuries

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

VA Medical Center, Bronx

The Bronx, New York, 10468, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

1.25 mg enalaprilat IV

Drug

an angiotensin converting enzyme (ACE) inhibitor given to lower blood pressure (BP) and measure cerebral blood flow (CBF)

Head up tilt (HUT)

Other

45 degree head-up tilt to lower blood pressure and measure cerebral blood flow.

Primary outcomes

  1. Systolic Blood Pressure

    Time frame: acute testing

    Systolic blood pressure during head-up tilt in subjects with spinal cord injury without drug intervention

Secondary outcomes

  1. Cerebral Blood Flow

    Time frame: acute testing

    Measurement of middle cerebral artery blood flow velocity supine and during head-up tilt

Sponsors and collaborators

Lead sponsor

VA Office of Research and Development

Fed

Registry information

Official study title

Systemic Hemodynamics and Cerebral Blood Flow in Persons With Tetraplegia

Important dates

Study start
2005
Primary completion
2009
Study completion
2012
First posted
Nov 4, 2005
Registry last updated
Feb 25, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.