Asymptomatic Carotid Stenosis: Cognitive Function and Plaque Correlates
| Status: | Completed |
|---|---|
| Conditions: | Cardiology |
| Therapuetic Areas: | Cardiology / Vascular Diseases |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 4/17/2018 |
| Start Date: | May 15, 2011 |
| End Date: | February 28, 2018 |
Carotid artery plaques are known to cause stroke. Cognitive impairment is an insidious but
poorly understood problem in patients with carotid plaques. Cognitive function describes how
people perform mental processes such as thinking, learning and problem solving. Asymptomatic
carotid plaques may affect 1 million Veterans who may be at risk for cognitive impairment. In
this study, the investigators will uncover the extent of cognitive impairment in Veterans
with carotid stenosis who are currently labeled "asymptomatic". Programs to prevent or
mitigate cognitive impairment will depend on identifying the mechanisms by which this occurs.
The investigators will use sophisticated 3D imaging techniques developed by the group to
measure the structure and composition of plaques, number of particles breaking off from them,
blood levels of chemicals that could disrupt them, and blood flow restriction to the brain
from them. This will help identify patients at risk for cognitive impairment who may benefit
from preventative measures and improve selection of patients to decrease unnecessary surgical
procedures.
poorly understood problem in patients with carotid plaques. Cognitive function describes how
people perform mental processes such as thinking, learning and problem solving. Asymptomatic
carotid plaques may affect 1 million Veterans who may be at risk for cognitive impairment. In
this study, the investigators will uncover the extent of cognitive impairment in Veterans
with carotid stenosis who are currently labeled "asymptomatic". Programs to prevent or
mitigate cognitive impairment will depend on identifying the mechanisms by which this occurs.
The investigators will use sophisticated 3D imaging techniques developed by the group to
measure the structure and composition of plaques, number of particles breaking off from them,
blood levels of chemicals that could disrupt them, and blood flow restriction to the brain
from them. This will help identify patients at risk for cognitive impairment who may benefit
from preventative measures and improve selection of patients to decrease unnecessary surgical
procedures.
Carotid artery stenosis is a well-known cause of atheroembolic stroke. Stroke prevention in
these patients has been the focus of intense investigation. Cognitive impairment is a more
insidious but poorly understood outcome in patients with "asymptomatic" carotid stenosis who
have not suffered a stroke. Cognitive function describes how a person produces and controls
mental processes such as thinking, learning, and problem solving. It is an important outcome
measure that affects patient well-being and their ability to live independent productive
lies. It is well-known that cognitive impairment coexists in patients with stroke from
carotid stenosis. However, isolated cognitive deficits in patients with asymptomatic carotid
stenosis have not been looked for, and have therefore not been reported in any detail.
Asymptomatic carotid stenosis affects 2-12% of people. With 23.4 million Veterans in the
country, at least 1 million (4.3%) have asymptomatic carotid stenosis and are at risk for
cognitive impairment. A subset analysis of the Cardiovascular Health Study found cognitive
decline in 34% of 32 patients with asymptomatic carotid stenosis. In this proposal, the
investigators will define the extent of initial and progressive cognitive impairment in
Veterans with carotid stenosis who are currently labeled as "asymptomatic" in the absence of
a focal neurologic deficit (stroke, transient ischemic attack). Programs to prevent,
postpone, or mitigate cognitive impairment in patients with carotid stenosis will depend on
the identification of mediators for cognitive impairment. Microembolic brain injury and
cerebral hypoperfusion have been associated with cognitive impairment in elderly individuals.
Therefore plaque architecture, plaque composition, microembolic counts, serum inflammatory
markers, and cerebral hypoperfusion are likely mediators of impaired cognition in patients
with asymptomatic carotid stenosis. As part of this proposal, the investigators will identify
the biological mechanisms by which carotid stenosis could result in cognitive impairment.
The goal of this proposal is to perform a systematic, adequately powered study to measure the
magnitude of cognitive impairment in asymptomatic carotid stenosis, its impact on quality of
life, and its potential pathophysiological mechanisms. Information from this study will
define an unsuspected morbidity of carotid stenosis and identify subsets of patients at risk
for cognitive impairment. It will form the foundation for future studies on prevention,
pre-emptive treatment, or rehabilitation of patients with carotid stenosis. It will also
improve the selection of patients with carotid stenosis to decrease unnecessary
revascularization procedures.
Specific Aim 1 will assess if patients with asymptomatic carotid stenosis differ in cognitive
function compared to age-matched controls without carotid stenosis but with similar vascular
risk profiles. The investigators hypothesize that in patients with asymptomatic carotid
stenosis 50% who survive stroke free for 2 years; the change in overall and domain-specific
cognitive function will be significantly different compared to those without stenosis. The
study will recruit 284 subjects and will detect a clinically significant difference in
cognitive score with 90% power. The investigators will use a novel battery of cognitive tests
specifically developed to address the unique issues relating to carotid stenosis.
Specific Aim 2 will define plaque-morphometric, biologic, and hemodynamic characteristics
that correlate with cognitive impairment in patients with asymptomatic carotid stenosis. The
investigators hypothesize that carotid plaque architecture, plaque composition, microembolic
counts, serum pro-inflammatory markers, and cerebral hypoperfusion could each mediate
cognitive decline over a 2-year follow-up period. The investigators will implement a novel
clinical 3D B-mode ultrasound imaging technique developed to obtain reliable serial plaque
measurements.
Specific Aim 3 will measure the impact of cognitive impairment on quality of life. The
investigators hypothesize that at 2 years, regardless of plaque features, cognitive
impairment will correlate with a reduction in health-related quality of life measures.
these patients has been the focus of intense investigation. Cognitive impairment is a more
insidious but poorly understood outcome in patients with "asymptomatic" carotid stenosis who
have not suffered a stroke. Cognitive function describes how a person produces and controls
mental processes such as thinking, learning, and problem solving. It is an important outcome
measure that affects patient well-being and their ability to live independent productive
lies. It is well-known that cognitive impairment coexists in patients with stroke from
carotid stenosis. However, isolated cognitive deficits in patients with asymptomatic carotid
stenosis have not been looked for, and have therefore not been reported in any detail.
Asymptomatic carotid stenosis affects 2-12% of people. With 23.4 million Veterans in the
country, at least 1 million (4.3%) have asymptomatic carotid stenosis and are at risk for
cognitive impairment. A subset analysis of the Cardiovascular Health Study found cognitive
decline in 34% of 32 patients with asymptomatic carotid stenosis. In this proposal, the
investigators will define the extent of initial and progressive cognitive impairment in
Veterans with carotid stenosis who are currently labeled as "asymptomatic" in the absence of
a focal neurologic deficit (stroke, transient ischemic attack). Programs to prevent,
postpone, or mitigate cognitive impairment in patients with carotid stenosis will depend on
the identification of mediators for cognitive impairment. Microembolic brain injury and
cerebral hypoperfusion have been associated with cognitive impairment in elderly individuals.
Therefore plaque architecture, plaque composition, microembolic counts, serum inflammatory
markers, and cerebral hypoperfusion are likely mediators of impaired cognition in patients
with asymptomatic carotid stenosis. As part of this proposal, the investigators will identify
the biological mechanisms by which carotid stenosis could result in cognitive impairment.
The goal of this proposal is to perform a systematic, adequately powered study to measure the
magnitude of cognitive impairment in asymptomatic carotid stenosis, its impact on quality of
life, and its potential pathophysiological mechanisms. Information from this study will
define an unsuspected morbidity of carotid stenosis and identify subsets of patients at risk
for cognitive impairment. It will form the foundation for future studies on prevention,
pre-emptive treatment, or rehabilitation of patients with carotid stenosis. It will also
improve the selection of patients with carotid stenosis to decrease unnecessary
revascularization procedures.
Specific Aim 1 will assess if patients with asymptomatic carotid stenosis differ in cognitive
function compared to age-matched controls without carotid stenosis but with similar vascular
risk profiles. The investigators hypothesize that in patients with asymptomatic carotid
stenosis 50% who survive stroke free for 2 years; the change in overall and domain-specific
cognitive function will be significantly different compared to those without stenosis. The
study will recruit 284 subjects and will detect a clinically significant difference in
cognitive score with 90% power. The investigators will use a novel battery of cognitive tests
specifically developed to address the unique issues relating to carotid stenosis.
Specific Aim 2 will define plaque-morphometric, biologic, and hemodynamic characteristics
that correlate with cognitive impairment in patients with asymptomatic carotid stenosis. The
investigators hypothesize that carotid plaque architecture, plaque composition, microembolic
counts, serum pro-inflammatory markers, and cerebral hypoperfusion could each mediate
cognitive decline over a 2-year follow-up period. The investigators will implement a novel
clinical 3D B-mode ultrasound imaging technique developed to obtain reliable serial plaque
measurements.
Specific Aim 3 will measure the impact of cognitive impairment on quality of life. The
investigators hypothesize that at 2 years, regardless of plaque features, cognitive
impairment will correlate with a reduction in health-related quality of life measures.
Inclusion Criteria:
- asymptomatic 50% carotid stenosis or more
Exclusion Criteria:
- previous stroke or transient ischemic attack (TIA)
- severe medical illness that would interfere with evaluation of outcomes or reduce the
likelihood of a 2-year follow-up
- carotid occlusion
- patients scheduled for carotid revascularization procedures
We found this trial at
1
site
Baltimore, Maryland 21201
Principal Investigator: Brajesh K Lal, MD
Phone: 410-605-7130
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