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

NCT ID: NCT00248807

Last Updated: 2025-02-25

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2005-10-31
• Study Completion Date: 2012-04-30

Brief Summary

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.

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.

Conditions

Orthostatic Hypotension; Spinal Cord Injuries

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: HEALTH_SERVICES_RESEARCH
• Blinding Strategy: NONE

Study Groups

ARM 1

Head-up tilt maneuver without drug in subjects with spinal cord injury

Group Type: PLACEBO_COMPARATOR

Head up tilt (HUT)

Intervention Type: OTHER

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

ARM 3

Head-up tilt maneuver without drug in able-bodied controls

Group Type: PLACEBO_COMPARATOR

Head up tilt (HUT)

Intervention Type: OTHER

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

ARM 2

Head-up tilt maneuver with an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat) in subjects with spinal cord injury

Group Type: ACTIVE_COMPARATOR

1.25 mg enalaprilat IV

Intervention Type: DRUG

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

Head up tilt (HUT)

Intervention Type: OTHER

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

ARM 4

Head-up tilt maneuver with an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat) in able-bodied controls.

Group Type: ACTIVE_COMPARATOR

1.25 mg enalaprilat IV

Intervention Type: DRUG

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

Head up tilt (HUT)

Intervention Type: OTHER

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

Interventions

1.25 mg enalaprilat IV

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

Intervention Type: DRUG

Head up tilt (HUT)

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

Intervention Type: OTHER

Eligibility 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

VA Office of Research and Development

FED

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Jill Wecht, EdD

Role: PRINCIPAL_INVESTIGATOR

VA Medical Center, Bronx

Locations

VA Medical Center, Bronx

The Bronx, New York, United States

Countries

United States

References

Handrakis JP, DeMeersman RE, Rosado-Rivera D, LaFountaine MF, Spungen AM, Bauman WA, Wecht JM. Effect of hypotensive challenge on systemic hemodynamics and cerebral blood flow in persons with tetraplegia. Clin Auton Res. 2009 Feb;19(1):39-45. doi: 10.1007/s10286-008-0496-6. Epub 2008 Oct 11.

Reference Type: RESULT

PMID: 18850311 (View on PubMed)

Other Identifiers

00517

Identifier Type: OTHER

Identifier Source: secondary_id

B3346-V

Identifier Type: -

Identifier Source: org_study_id