An observational study in Antiphospholipid Syndrome, Stenosis and Intracranial Stenosis, sponsored by Chinese University of Hong Kong. Enrolling by invitation at 1 site in Hong Kong. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-26.
Sponsored by Chinese University of Hong Kong · Observational
Antiphospholipid syndrome (APS) is an important cause of young stroke which could result in major disability. Cohort studies suggested that 17% of young ischemic stroke were accountable by APS (1). Although warfarin has been the mainstay of treatment in APS for the past decades, recurrent thromboembolism occurred up to 10% of warfarinized patients with APS (2, 3). These observations call for an in-depth understanding of disease mechanisms secondary to antiphospholipid antibodies (aPL). Contrary to traditional understanding, recent evidence suggested mechanisms of cerebrovascular ischemia in APS are far more complex than hypercoagulability alone.
In the proposed cross-sectional study, we aim to determine the prevalence of intracranial stenosis, and to explore the correlations between the neuroimaging findings and the immunological as well as clinical features in patients with APS.
In the proposed cross-sectional study, we aim to determine the prevalence of intracranial stenosis, and to explore the correlations between the neuroimaging findings and the immunological as well as clinical features in patients with APS.
In the proposed cross-sectional study, we aim to determine the prevalence of intracranial stenosis, and to explore the correlations between the neuroimaging findings and the immunological as well as clinical features in patients with APS.
Upon reviewing the clinical and laboratory information in the medical specialist out-patient clinics, electronic patient record and/or through the Clinical Data Analysis And Reporting System (CDARS), investigators shall identify and recruit on-site APS patients who fulfilled the modified Sapporo criteria, currently aged ≥18 years, and receive care from the Prince of Wales Hospital.
Investigators shall then arrange a study clinic visit for eligible patients. After obtaining an informed consent, patients will be subjected to cognitive assessment (Hong Kong Version of Montreal Cognitive Assessment (HK-MoCA)), blood pressure, pulse, body mass index measurement, urinalysis, and contrast MRI brain (see imaging assessment below). Demographic data (age, gender, smoking, drinking, ambulatory status), medical comorbidities (concurrent autoimmune diseases and their organ involvement, history of catastrophic APS, hypertension, hyperlipidemia, diabetes mellitus, congestive heart failure, number and type of previous arterial or venous thromboembolism), laboratory parameters (complete blood count, liver and renal function test, C-reactive protein, erythrocyte sediment rate, high sensitive C-reaction protein, plasminogen activator inhibitor-1, neurofilament light chain, titers of autoimmune markers including anti-nuclear antibodies, extractable nuclear antigen antibodies, aPLs, rheumatoid factor, anti-cyclic citrullinated peptide antibody, etc.), concurrent medications (aspirin, warfarin, direct oral anticoagulants, antihypertensives, statins, steroid, immunosuppressants, etc.). In another ongoing prospective Brain Health Longitudinal study which contained stroke- and dementia free participants (CREC Ref. No: 2018.148), investigators shall identify age- and gender-matched individuals without aPLs as controls. They will be assessed in the same manner as the APS patients.
121 studies on the registry are indexed under Antiphospholipid Syndrome; 52 are open to participants now.
This study's planned enrollment of 60 is below the median of 156 across 50 observational studies indexed under Antiphospholipid Syndrome.
Browse Antiphospholipid Syndrome studies →Chinese University of Hong Kong is the lead sponsor of 1,454 studies on the registry; 474 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
Counted across the registry records on this site, refreshed daily.
Adults with or without APS
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.
Patients diagnosed with APS who fulfilled the modified Sapporo criteria:
i. Lupus anticoagulant positivity requires screening, mixing, and confirmation test as per International Society of Thrombosis and Hemostasis guidelines (11). ii. Anticardiolipin antibodies positivity requires a medium to high titer IgG and/or IgM level by ELISA assays. iii. Anti-β2 glycoprotein antibodies positivity requires a >99th titer IgG and/or IgM level by ELISA assays.
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.
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.
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.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
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.
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.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigators shall recruit patients with the following criteria: 1. Diagnosed with APS who fulfilled the modified Sapporo criteria: 1. at least one clinical criterion (vascular thrombosis or pregnancy morbidity); and 2. laboratory criteria (aPL positivity twice, 12 weeks apart): i. Lupus anticoagulant positivity requires screening, mixing, and confirmation test as per International Society of Thrombosis and Hemostasis guidelines (11). ii. Anticardiolipin antibodies positivity requires a medium to high titer IgG and/or IgM level by ELISA assays. iii. Anti-β2 glycoprotein antibodies positivity requires a \>99th titer IgG and/or IgM level by ELISA assays. 2. Patients age ≥18 years 3. Patients who are able to provide an informed consent to study procedures
Diagnostic Test: Imaging assessment · Diagnostic Test: Neurosonology assessment · Diagnostic Test: Blood Test
From the ongoing prospective Brain Health Longitudinal study which contained stroke- and dementia free participants (CREC Ref. No: 2018.148), investigators shall identify age- and gender-matched individuals without aPLs as controls
Diagnostic Test: Imaging assessment · Diagnostic Test: Neurosonology assessment · Diagnostic Test: Blood Test
Investigators shall perform cranial MRI examinations. The scanning protocol will employ an MRI scan protocol with T1-weighted, T2-weighted, FLAIR, susceptibility weighted imaging, diffusion weighted imaging, and time-of-flight magnetic resonance angiography (MRA) sequences. In addition, high-resolution magnetic resonance vessel wall imaging (HRMRI) allows assessment of the vessel wall using specific the SPACE sequence and the MATCH sequence. Assessors of the HRMRI images shall be blinded to the group allocation and clinical information.
Investigators shall perform carotid duplex ultrasonography (CD) assessment, focusing on the peak systolic (PSV) and end diastolic velocity (EDV) of bilateral extracranial internal carotid arteries (ICA) Brightness mode imaging shall gauge the intimal thickness and plaque characteristics (if any) of bilateral ICAs.
Nine milliliters of EDTA blood will be drawn during the research clinic visit for evaluation of the degree of neurovascular inflammation. Serum plasminogen activator inhibitor-1 (PAI-1) and high-sensitive C-reactive protein (hsCRP) are markers of vascular inflammation, atherosclerosis, and thrombotic risk. Serum neurofilament light chain (NfL) is a biomarker for neuroaxonal injury that correlates with small vessel disease.
Radiological evidence of intracranial arterial stenosis
Defined as the presence of \>50% stenosis of any intracranial arteries (ICA, MCA, anterior cerebral arteries, posterior cerebral arteries, basilar artery, or vertebral arteries) or presence of arterial plaques in vessel wall imaging.
Time frame: 31／01／2026
Other radiological outcomes
Including the presence and pattern of enhancing intracranial plaques (concentric vs eccentric), Age-related White Matter Change Scale ≥ 2, white matter hyperintensity volume, presence of lacunes, cerebral microbleeds, extracranial ICA plaques, normalized total brain volume. Secondary biochemical outcomes include level of hs-CRP and PAI-1. The relationship between the neuroimaging outcomes and the clinical characteristics of patients with APS will be evaluated.
Time frame: 31／01／2026
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.
No contact was published for this record. The registry link below has the sponsor’s details.
Get 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.
Chinese University of Hong Kong →