An observational study to determine if individuals with increased platelet FcyRIIa will have a higher risk of ischemic events.
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%.
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.
Individuals with who have experience a Stroke or TIA
Cohort
Prospective
Medical Imaging
Diagnostic testmagnetic 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.
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.
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.
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University of California, Los Angeles
Lead sponsor
University of Pittsburgh Medical Center
Collaborator
University of Chicago
Collaborator
Bay State Clinical Trials, Inc.
Collaborator
Yale University
Collaborator
University of Vermont
Collaborator
University of Southern California
Collaborator
