Prevalence and Etiologies of Intracranial Stenosis in Patients With Antiphospholipid Syndrome (ICAS_APS)

May 21, 2026 updated by: Dr. IP Yiu Ming Bonaventure, Chinese University of Hong Kong

Prevalence and Etiologies of Intracranial Stenosis in Patients With Antiphospholipid Syndrome: a Cross Sectional Study (ICAS_APS)

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Hong Kong
      • Hong Kong, Hong Kong
        • Chinese University of Hong Kong

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Adults with or without APS

Description

Inclusion Criteria:

  1. Patients 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

Exclusion Criteria:

  1. Patient with established neurological disease, such as stroke, cerebral venous thrombosis, vasculitis of the central nervous system, cerebral lupus, etc.
  2. Patient contraindicated to contrast MRI scans. E.g. claustrophobia, allergy to gadolinium contrast, MRI incompatible implants, estimated glomerular filtration rate of < 30mL/min/1.73m2.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Patients diagnosed with APS

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
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.
Diagnostic test: Neurosonology assessment
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.
Diagnostic test: Blood Test
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.
Controls
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
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.
Diagnostic test: Neurosonology assessment
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.
Diagnostic test: Blood Test
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.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Radiological evidence of intracranial arterial stenosis
Time Frame: 31／01／2026
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.
31／01／2026

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Other radiological outcomes
Time Frame: 31／01／2026
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.
31／01／2026

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Chinese University of Hong Kong

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Bonaventure Yiu Ming IP, MB ChB, Chinese University of Hong Kong

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 12, 2022

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 31, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 17, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 13, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 13, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 17, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 26, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 21, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CREC 2022.352

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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