An observational study in Stroke, TIA and Ischemic Stroke, sponsored by University of California, Los Angeles. Recruiting at 1 site in United States. Open to participants aged 30 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-11.
Sponsored by University of California, Los Angeles · Observational
An observational study to determine if individuals with increased platelet FcyRIIa will have a higher risk of ischemic events.
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.
2,612 studies on the registry are indexed under Ischemic Stroke; 971 are open to participants now.
This study's planned enrollment of 250 is below the median of 300 across 771 observational studies indexed under Ischemic Stroke.
Browse Ischemic Stroke studies →University of California, Los Angeles is the lead sponsor of 1,170 studies on the registry; 195 are open to participants now.
Of its 95 completed or terminated interventional studies of FDA-regulated products, 70 (74%) have results posted.
Compared within Ischemic Stroke, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Stroke. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Individuals with who have experience a Stroke or TIA
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
TIA (transient ischaemic attack)
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Diagnostic Test: Medical Imaging
magnetic resonance imaging
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.
Time frame: 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.
Time frame: 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.
Time frame: 1 year
Plan to share: No
No publications or documents are linked to this record.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of California, Los Angeles →