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| ID | Type | Description | Link |
|---|---|---|---|
| 00517 | Other Identifier | JJP VAMC IRB |
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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.
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| ARM 1 | Placebo Comparator | Head-up tilt maneuver without drug in subjects with spinal cord injury |
|
| ARM 3 | Placebo Comparator | Head-up tilt maneuver without drug in able-bodied controls |
|
| ARM 2 | Active Comparator | Head-up tilt maneuver with an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat) in subjects with spinal cord injury |
|
| ARM 4 | Active Comparator | Head-up tilt maneuver with an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat) in able-bodied controls. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 1.25 mg enalaprilat IV | Drug | an angiotensin converting enzyme (ACE) inhibitor given to lower blood pressure (BP) and measure cerebral blood flow (CBF) |
|
| Measure | Description | Time Frame |
|---|---|---|
| Systolic Blood Pressure | Systolic blood pressure during head-up tilt in subjects with spinal cord injury without drug intervention | acute testing |
| Measure | Description | Time Frame |
|---|---|---|
| Cerebral Blood Flow | Measurement of middle cerebral artery blood flow velocity supine and during head-up tilt | acute testing |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Jill Wecht, EdD | VA Medical Center, Bronx | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| VA Medical Center, Bronx | The Bronx | New York | 10468 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 18850311 | Result | 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. |
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All subjects recruited completed all testing procedures.
Recruitment has been completed.
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| ID | Title | Description |
|---|---|---|
| FG000 | Subjects With Spinal Cord Injury (SCI) | Subjects with SCI underwent a 45 degree head-up tilt maneuver to lower blood pressure and measure cerebral blood flow with and without enalaprilat (1.25 mg). |
| FG001 | Subjects Without SCI (Non-SCI) | Subjects without SCI (non-SCI) underwent a 45 degree head-up tilt maneuver to lower blood pressure and measure cerebral blood flow with and without enalaprilat (1.25 mg). |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
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| ID | Title | Description |
|---|---|---|
| BG000 | Subjects With Spinal Cord Injury | Subjects with spinal cord injury underwent a 45 degree head-up tilt maneuver to lower blood pressure and monitor cerebral blood flow on 2 study visits. The first visit subject underwent the head-up tilt maneuver without drug and on the second visits subject underwent the head-up tilt maneuver following oral administration of an angiotensin converting enzyme inhibitor (ACE: 1.25 mg enalaprilat). |
| Units | Counts |
|---|---|
| Participants |
|
| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical | Count of Participants |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Systolic Blood Pressure | Systolic blood pressure during head-up tilt in subjects with spinal cord injury without drug intervention | convenience sample | Posted | Mean | Standard Deviation | mmHg | acute testing |
|
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | ARM 1 | 45 degree head-up tilt to lower blood pressure and measure cerebral blood flow in subjects with spinal cord injury. |
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Did not assess carbon dioxide levels or the severity of spinal cord injury, which may have contributed to the results.
| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Dr. Jill M. Wecht; Principal Investigator | James J Peters VAMC | 718 584-9000 | 3122 | JM.Wecht@va.gov |
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| ID | Term |
|---|---|
| D007024 | Hypotension, Orthostatic |
| D013119 | Spinal Cord Injuries |
| D007022 | Hypotension |
| ID | Term |
|---|---|
| D054971 | Orthostatic Intolerance |
| D054969 | Primary Dysautonomias |
| D001342 | Autonomic Nervous System Diseases |
| D009422 | Nervous System Diseases |
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| Head up tilt (HUT) | Other | 45 degree head-up tilt to lower blood pressure and measure cerebral blood flow. |
|
| BG001 | Non-spinal Cord Injured Subjects | Non-spinal cord injured subjects underwent a 45 degree head-up tilt maneuver to lower blood pressure and monitor cerebral blood flow on 2 study visits. The first visit subject underwent the head-up tilt maneuver without drug and on the second visits subject underwent the head-up tilt maneuver following oral administration of an angiotensin converting enzyme inhibitor (ACE: 1.25 mg enalaprilat). |
| BG002 | Total | Total of all reporting groups |
| Participants |
|
| Age, Continuous | Mean | Standard Deviation | years |
|
| Sex: Female, Male | Count of Participants | Participants |
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| Region of Enrollment | Number | participants |
|
| ARM 3 |
45 degree head-up tilt to lower blood pressure and measure cerebral blood flow in subjects with spinal cord injury following intravenous administration of an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat). |
| OG003 | ARM 4 | 45 degree head-up tilt to lower blood pressure and measure cerebral blood flow in able-bodied control subjects following intravenous administration of an angiotensin converting enzyme inhibitor (1.25 mg enalaprilat). |
|
|
| Secondary | Cerebral Blood Flow | Measurement of middle cerebral artery blood flow velocity supine and during head-up tilt | Posted | Mean | Standard Deviation | cm/sec | acute testing |
|
|
|
| 0 |
| 19 |
| 0 |
| 19 |
| EG001 | ARM 2 | 45 degree head-up tilt to lower blood pressure and measure cerebral blood flow in able-bodied controls. | 0 | 11 | 0 | 11 |
| EG002 | ARM 3 | 1.25 mg enalaprilat IV and 45 degree head-up tilt to lower blood pressure and measure cerebral blood flow in subjects with spinal cord injury. | 0 | 19 | 0 | 19 |
| EG003 | ARM 4 | 1.25 mg enalaprilat IV and 45 degree head-up tilt to lower blood pressure and measure cerebral blood flow in able-bodied controls. | 0 | 11 | 0 | 11 |
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| D014652 | Vascular Diseases |
| D002318 | Cardiovascular Diseases |
| D013118 | Spinal Cord Diseases |
| D002493 | Central Nervous System Diseases |
| D020196 | Trauma, Nervous System |
| D014947 | Wounds and Injuries |