StrokeFCGNCT05518305
Platelet Expression of FcγRIIa and Arterial Hemodynamics to Predict Recurrent Stroke in Intracranial Atherosclerosis
An observational study of Stroke and TIA, run by University of California, Los Angeles at 1 site in United States.
Trial summary
An observational study to determine if individuals with increased platelet FcyRIIa will have a higher risk of ischemic events. Read more about this study
- Who is it for?
- Ages 30 years and olderHealthy volunteers can take part
- Conditions the study is for
- Stroke, TIA, Ischemic Stroke
- What is being tested?
- Medical Imaging
- How many people
- 250 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Sep 2022to 30 Sep 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 30 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Individuals with who have experience a Stroke or TIA
Who may be able to join
- Stroke is defined as symptoms lasting >24 hours and associated with imaging evidence of acute ischemia in the distribution of the stenotic vessel on head CT or brain MRI. Minor stroke is defined as NIHSS<6, as used in prior studies.
- Eligible TIA, defined as transient neurological symptoms lasting <24 hours, need to be: a) accompanied by DWI abnormalities in the distribution of the stenotic artery; or b) multiple (>1), stereotyped events associated with unequivocal ischemic symptoms (i.e. weakness, aphasia, diplopia), and attributed to the symptomatic artery. The intent of these restrictive inclusion criteria for TIA is to exclude potential stroke mimics.
- ICAD should involve the intracranial carotid, middle cerebral, intracranial vertebral or basilar arteries. Isolated anterior and posterior cerebral artery stenosis is not included as it is uncommon in these locations and non-invasive criteria for high-grade ICAD are not well established for these vessels.
- Stenosis 50-99% will be quantified by CTA. The criteria for 50-99% are: measured stenosis by WASID criteria (percent stenosis = (1-[diameter stenosis/diameter normal]) x 100%.
- Age ³30; those 30-49 years of age must also have the presence of established atherosclerotic disease in another vascular bed (coronary, extracranial carotid, peripheral) or the presence of 2 or more risk factors (hypertension, diabetes mellitus, hyperlipidemia, tobacco abuse within the last 2 years). The rationale for this criterion is to exclude non-atherosclerotic vasculopathies.
- Provide informed consent for participation in the study.
Who cannot join
- Other determined etiology or established cause of the acute stroke or TIA: atrial fibrillation, mitral stenosis, mechanical valve, intracardiac thrombus or vegetation, dilated cardiomyopathy or ejection fraction <30%, proximal extracranial carotid or vertebral stenosis >50%.
- Contraindications to MRI, including MR-incompatible metallic implants (i.e. certain artificial cardiac valves, penile implants, other prosthesis), implanted electronic devices (i.e. pacemaker/defibrillator, neurostimulators, cochlear implants), other potentially mobile ferromagnetic material (i.e. shrapnel, magnetic aneurysm clips), pregnancy (women in fertile age should have a negative pregnancy test), lactation, morbid obesity, and severe claustrophobia.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Ronald Reagan UCLA Medical Center
Los Angeles, California, 90095
Ryan Apfel, rapfel@mednet.ucla.edu
David Liebeskind, MD
About this study
Official title: Platelet Expression of FcγRIIa and Arterial Hemodynamics to Predict Recurrent Stroke in Intracranial Atherosclerosi
An observational study to determine if individuals with increased platelet FcyRIIa will have a higher risk of ischemic events.
Read the detailed description
Recurrent ischemic stroke due to intracranial atherosclerotic disease (ICAD) is extremely common despite treatment with anti-platelet medications. Heterogeneity of the arterial architecture and associated blood flow changes in ICAD-related stenoses result in different patterns of wall shear stress (WSS) from one individual to the next. Such wall shear stress can be readily quantified with computational fluid dynamics (CFD) from noninvasive CT angiography (CTA), routinely acquired in patients with minor stroke or transient ischemic attack (TIA) due to ICAD. These shear stress changes in blood flow promote platelet aggregation and thereby alter the response to anti-platelet therapy. Additionally, greater platelet FcγRIIa expression increases platelet reactivity and promotes thrombosis when platelets are exposed to increased shear stress. In the coronary circulation, greater platelet expression of FcγRIIa identifies patients at greater risk of recurrent cardiovascular events, including stroke. Numerous mechanisms have been invoked in the recurrence of ischemia in ICAD, yet focused research on the pathophysiology of shear stress and platelet activation has not been evaluated to explain the high rate of imaging evidence and clinical strokes following minor stroke or TIA due to ICAD. Given the shared pathology of coronary artery disease and ICAD, the data suggest that individual differences in CFD-derived WSS and platelet FcγRIIa expression may inform a precision medicine strategy to prevent recurrent stroke. The investigators developed a novel approach to validate CTA CFD values of WSS in stenoses in ICAD with precision 3D cerebrovascular models, including data from the landmark SAMMPRIS trial. In other collaborations, The investigators have separately studied the potential impact of elevated WSS on stroke recurrence in ICAD and conducted an observational multicenter study on mechanisms of recurrent stroke in ICAD. The investigators and others have demonstrated that greater platelet FcγRIIa expression increases the activation of platelets in response to agonists and shear stress. These synergies now enable us to investigate how the interaction of anti-platelet therapies with individual platelet expression of FcγRIIa and WSS calculated from patient-specific CTA CFD may explain recurrent ischemia after minor stroke or TIA due to ICAD. The investigators hypothesize that the incidence of recurrent silent ischemia on MRI and clinical strokes by 1 year after minor stroke or TIA due to ICAD will be predicted by quantifying individual risk determined by platelet FcγRIIa expression and focal elevations in WSS due to stenosis.
- Conditions
- Stroke, TIA, Ischemic Stroke, Ischemic
- Being tested
- Medical Imaging
- Keywords
- Stroke
- Medical subject headings
- Stroke, Ischemic Stroke, Ischemia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Medical ImagingDiagnostic test
magnetic resonance imaging
| Study group | Role | What they receive |
|---|---|---|
| All | Blood sampling and an MRI will be conducted alongside standard stroke cognitive tests upon enrollment. A follow-up three-month visit will check for adverse events and a follow-up cognitive stroke test. At 12 months, an MRI will be conducted alongside a cognitive test. Receives: Diagnostic Test: Medical Imaging |
What is being measured
The primary outcome is the main question the study is designed to answer.
Determine the impact of platelet FcγRIIa expression on 1-year risk of recurrent stroke in ICAD.
The investigators hypothesize that increased platelet FcγRIIa will be associated with a greater risk of ischemic events. Platelet FcγRIIa expression will be quantified in 250 subjects enrolled at 6 sites with stroke or TIA due to 50-99% ICAD to determine impact of FcγRIIa on 1-year risk of recurrent stroke, including clinical events and serial MRI.
Measured: 1 year
Quantify the impact of WSS from CTA CFD on 1-year risk of recurrent stroke in ICAD
The investigators hypothesize that high WSS and an elevated post-stenotic oscillatory shear index (OSI) that are stimuli of shear-induced platelet aggregation will confer an increased risk of recurrent ischemic stroke. We will use routinely acquired CTA in 250 subjects enrolled at 6 sites with stroke or TIA due to 50-99% ICAD to quantify the impact of WSS and post-stenotic OSI on 1-year risk of recurrent stroke, including clinical events and serial MRI.
Measured: 1 year
Develop a precision model to determine the risk of recurrent stroke 1 year after index events due to ICAD based on individual FcγRIIa expression and WSS from baseline CTA.
The investigators hypothesize that the 1-year recurrent stroke risk associated with high platelet FcγRIIa expression and high WSS will be more than additive.
Measured: 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Aug 2022
- Study start30 Sep 2022
- Primary completion30 Sep 2027 (estimated)
- Study completion30 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for StrokeStudies of the same condition, open and under way.
- More trials run by University of California, Los AngelesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 250 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Los Angeles
- Sponsor type
- University, hospital or other
- Collaborators
- University of Pittsburgh Medical Center, University of Chicago, Bay State Clinical Trials, Inc., Yale University, University of Vermont, University of Southern California
- Responsible party
- Principal investigator, David Liebeskind, University of California, Los Angeles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05518305
- Sponsor's protocol ID
- NS123734
- Acronym
- FCG
- Status last verified
- Jun 2026
- First submitted
- 24 Aug 2022
- Last updated
- 11 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 11 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Platelet Expression of FcγRIIa and Arterial Hemodynamics to Predict Recurrent Stroke in Intracranial Atherosclerosi
- ClinicalTrials.gov ID
- NCT05518305
- Acronym / sponsor ID
- FCG / NS123734
- Conditions
- Stroke, TIA, Ischemic Stroke, Ischemic
- Keywords
- Stroke
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 250 participants (estimated)
- Lead sponsor
- University of California, Los AngelesUniversity, hospital or other
- Collaborators
- University of Pittsburgh Medical Center, University of Chicago, Bay State Clinical Trials, Inc., Yale University, University of Vermont, University of Southern California
- Study start
- 30 Sep 2022 (actual)
- Primary completion
- 30 Sep 2027 (estimated)
- Study completion
- 30 Sep 2027 (estimated)
- First posted
- 26 Aug 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
An observational study to determine if individuals with increased platelet FcyRIIa will have a higher risk of ischemic events.
Detailed description
Recurrent ischemic stroke due to intracranial atherosclerotic disease (ICAD) is extremely common despite treatment with anti-platelet medications. Heterogeneity of the arterial architecture and associated blood flow changes in ICAD-related stenoses result in different patterns of wall shear stress (WSS) from one individual to the next. Such wall shear stress can be readily quantified with computational fluid dynamics (CFD) from noninvasive CT angiography (CTA), routinely acquired in patients with minor stroke or transient ischemic attack (TIA) due to ICAD. These shear stress changes in blood flow promote platelet aggregation and thereby alter the response to anti-platelet therapy. Additionally, greater platelet FcγRIIa expression increases platelet reactivity and promotes thrombosis when platelets are exposed to increased shear stress. In the coronary circulation, greater platelet expression of FcγRIIa identifies patients at greater risk of recurrent cardiovascular events, including stroke. Numerous mechanisms have been invoked in the recurrence of ischemia in ICAD, yet focused research on the pathophysiology of shear stress and platelet activation has not been evaluated to explain the high rate of imaging evidence and clinical strokes following minor stroke or TIA due to ICAD. Given the shared pathology of coronary artery disease and ICAD, the data suggest that individual differences in CFD-derived WSS and platelet FcγRIIa expression may inform a precision medicine strategy to prevent recurrent stroke. The investigators developed a novel approach to validate CTA CFD values of WSS in stenoses in ICAD with precision 3D cerebrovascular models, including data from the landmark SAMMPRIS trial. In other collaborations, The investigators have separately studied the potential impact of elevated WSS on stroke recurrence in ICAD and conducted an observational multicenter study on mechanisms of recurrent stroke in ICAD. The investigators and others have demonstrated that greater platelet FcγRIIa expression increases the activation of platelets in response to agonists and shear stress. These synergies now enable us to investigate how the interaction of anti-platelet therapies with individual platelet expression of FcγRIIa and WSS calculated from patient-specific CTA CFD may explain recurrent ischemia after minor stroke or TIA due to ICAD. The investigators hypothesize that the incidence of recurrent silent ischemia on MRI and clinical strokes by 1 year after minor stroke or TIA due to ICAD will be predicted by quantifying individual risk determined by platelet FcγRIIa expression and focal elevations in WSS due to stenosis.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| All | – | Diagnostic Test: Medical ImagingBlood sampling and an MRI will be conducted alongside standard stroke cognitive tests upon enrollment. A follow-up three-month visit will check for adverse events and a follow-up cognitive stroke test. At 12 months, an MRI will be conducted alongside a cognitive test. |
Who may qualify
- Ages
- 30 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Individuals with who have experience a Stroke or TIA
Key inclusion criteria (6 listed)
- Stroke is defined as symptoms lasting >24 hours and associated with imaging evidence of acute ischemia in the distribution of the stenotic vessel on head CT or brain MRI. Minor stroke is defined as NIHSS<6, as used in prior studies.
- Eligible TIA, defined as transient neurological symptoms lasting <24 hours, need to be: a) accompanied by DWI abnormalities in the distribution of the stenotic artery; or b) multiple (>1), stereotyped events associated with unequivocal ischemic symptoms (i.e. weakness, aphasia, diplopia), and attributed to the symptomatic artery. The intent of these restrictive inclusion criteria for TIA is to exclude potential stroke mimics.
- ICAD should involve the intracranial carotid, middle cerebral, intracranial vertebral or basilar arteries. Isolated anterior and posterior cerebral artery stenosis is not included as it is uncommon in these locations and non-invasive criteria for high-grade ICAD are not well established for these vessels.
- Stenosis 50-99% will be quantified by CTA. The criteria for 50-99% are: measured stenosis by WASID criteria (percent stenosis = (1-[diameter stenosis/diameter normal]) x 100%.
- Age ³30; those 30-49 years of age must also have the presence of established atherosclerotic disease in another vascular bed (coronary, extracranial carotid, peripheral) or the presence of 2 or more risk factors (hypertension, diabetes mellitus, hyperlipidemia, tobacco abuse within the last 2 years). The rationale for this criterion is to exclude non-atherosclerotic vasculopathies.
Key exclusion criteria (2 listed)
- Other determined etiology or established cause of the acute stroke or TIA: atrial fibrillation, mitral stenosis, mechanical valve, intracardiac thrombus or vegetation, dilated cardiomyopathy or ejection fraction <30%, proximal extracranial carotid or vertebral stenosis >50%.
- Contraindications to MRI, including MR-incompatible metallic implants (i.e. certain artificial cardiac valves, penile implants, other prosthesis), implanted electronic devices (i.e. pacemaker/defibrillator, neurostimulators, cochlear implants), other potentially mobile ferromagnetic material (i.e. shrapnel, magnetic aneurysm clips), pregnancy (women in fertile age should have a negative pregnancy test), lactation, morbid obesity, and severe claustrophobia.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Medical Imagingmagnetic resonance imaging | Diagnostic test | All |
Primary outcome
Determine the impact of platelet FcγRIIa expression on 1-year risk of recurrent stroke in ICAD.
Time frame: 1 year
The investigators hypothesize that increased platelet FcγRIIa will be associated with a greater risk of ischemic events. Platelet FcγRIIa expression will be quantified in 250 subjects enrolled at 6 sites with stroke or TIA due to 50-99% ICAD to determine impact of FcγRIIa on 1-year risk of recurrent stroke, including clinical events and serial MRI.
Quantify the impact of WSS from CTA CFD on 1-year risk of recurrent stroke in ICAD
Time frame: 1 year
The investigators hypothesize that high WSS and an elevated post-stenotic oscillatory shear index (OSI) that are stimuli of shear-induced platelet aggregation will confer an increased risk of recurrent ischemic stroke. We will use routinely acquired CTA in 250 subjects enrolled at 6 sites with stroke or TIA due to 50-99% ICAD to quantify the impact of WSS and post-stenotic OSI on 1-year risk of recurrent stroke, including clinical events and serial MRI.
Develop a precision model to determine the risk of recurrent stroke 1 year after index events due to ICAD based on individual FcγRIIa expression and WSS from baseline CTA.
Time frame: 1 year
The investigators hypothesize that the 1-year recurrent stroke risk associated with high platelet FcγRIIa expression and high WSS will be more than additive.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Jun 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Stroke and TIA, run by University of California, Los Angeles at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 11 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact David Liebeskind, MD ((310) 963-5539, dliebeskind@mednet.ucla.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Determine the impact of platelet FcγRIIa expression on 1-year risk of recurrent stroke in ICAD. (time frame: 1 year). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Jun 2026.