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Trial registered on ANZCTR


Registration number
ACTRN12624001097538
Ethics application status
Approved
Date submitted
25/07/2024
Date registered
12/09/2024
Date last updated
12/09/2024
Date data sharing statement initially provided
12/09/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Characterising sex and ethnicity-based differences in cerebrovascular dynamics using a CO2 stimulus.
Scientific title
Hemodynamic Encephalopathy Risk Study (HER Study): Characterising sex and ethnicity-based differences in cerebrovascular dynamics in Maori and Pakeha groups.
Secondary ID [1] 312591 0
None
Universal Trial Number (UTN)
Trial acronym
HER Study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Problem Studied: Stroke resilience. 334518 0
Problem Studied: Neurodegeneration resilience. 334669 0
Condition category
Condition code
Neurological 331133 331133 0 0
Studies of the normal brain and nervous system
Cardiovascular 331240 331240 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participant Experience Summary (3 interactions):

Interaction 1 – Recruitment and Consent: The participant pool will be recruited from posters advertised around the city (Auckland and Gisborne) and campuses (University of Auckland and Matai Medical Research Institute). Upon expressed interest to the recruiter, the recruiter will explain the research either over the phone, by email, or in person. Should the potential participant wish to join the study, a meeting with a researcher and the potential participant will be booked to complete the informed consent process over the phone or video call. The recruiter will then pass on the participants contact information to imaging centre administration to schedule Interactions 2 and 3.

Interaction 2 – Visit 1: Demographics, BP measurement, and Mock Scan:
Timing: Approximately 1-2 weeks after interaction 1.
The participant will be booked for a one-hour visit to the scanning centre. 24 hours before the visit, the participant will be asked to abstain from alcohol, exercise, and be encouraged to have good sleep. Participants will be asked to not eat 2 hours before the visit to minimise the effects of digestion in the measurements. The participant will receive a reminder email the day before for visit for pre-scan preparation and the researcher will verbally confirm adherence on the day. Provided the participant has followed the pre scan preparation:

During the visit:
• A member of the research team will first complete the demographic questionnaire form with the participant.
At this stage, and prior to measurement, the option to have a female or male chaperone will be offered to the participant during the time the researcher is collecting measurements. The main role of the chaperone is to be physically present during the consultation and to directly observe all contact between the researcher and participant. The chaperone will ensure the protocol is followed and correctly documented, and intervene if the researcher acts inappropriately. The chaperone will adhere to the Medical Council of New Zealand Information Sheet and Policy 2020 standards. [https://www.mcnz.org.nz/support/support-for-patients/chaperones/].

• The participant will then be asked to test several gas masks for an ideal fit and to lie down. A finger heart rate monitor will be attached, the mask will be placed on the participant, and headphones will be provided playing MRI scanner sounds. This will simulate the MRI experience to prepare the participant before the scan. This will last for 10 minutes. Five minutes into rest, 3 brachial blood pressure cuff measurements will be taken for consistent measurement followed by arterial tonometry (a pencil based pressure reader) to measure pulse wave velocity (PWV) by reading the blood signal at the neck and femoral artery. A measure of distance between both measurements will also be collected using a tape measure.
• The participant will then practice breathing a carbon dioxide enriched gas blend (gas blend (5% CO2, 21% O2, and 74% Nitrogen) for 10 minutes to make sure they are comfortable with the sensation, which may provoke anxiety. 5% CO2 is completely safe for the human body and little to no sensation is expected. It can comfortably be inhaled and has been used in MRI scanners before at higher percentages for 15 minutes at a time in a young and older cohort [Miller:10.3389/fphys.2018.01096]. Their blood pressure will be taken thrice again at 5 minutes with CO2, followed again by the arterial tonometry.

Interaction 3 – Visit 2: MRI, Ultrasound (US), and Blood Sample:
Timing: As soon as possible after interaction 2. Estimated 1 week.
The participant will be booked by imaging centre admin for a two-hour visit. Availability for this visit will be confirmed during the scheduling of visit 1.
24 hours before the visit, the participant will be asked to abstain from alcohol, exercise, and be encouraged to have good sleep. Participants will be asked to not eat 2 hours before the scan to minimise the effects of digestion. The participant will receive a reminder email the day before for visit for pre-scan preparation and the researcher will verbally confirm adherence on the day. Provided the participant has followed the pre scan preparation:
• The participant and researcher will move into the MRI scanner module and similar equipment to the mock scan will be placed on the participant.
• The participant will then be imaged using the MR protocol detailed in the next section. The scan is non-invasive and does not involve any harmful substances or needles. Midway through (~12 minutes into scan), the CO2 enriched gas blend will be delivered and the participant will breath the gas for ~10-12 minutes (dependent on participant heart rate) to image changes in vascular flow. We are aware of the time commitment and comfort of participants, and as such have developed the entire MRI scanning protocol to be approximately 30 minutes.
• After the MRI scan, the participant will be immediately transported with the research team to the ultrasound scan room where they will receive a cardiac echo ultrasound scan which will take approximately 30 minutes. 15 minutes breathing regular air, and ~15 minutes breathing the gas blend.
• Finally, the research team will accompany the participant to the blood clinic, where blood samples will be collected.

MRI Protocol: Scan Time 30 minutes. Below describes the MR sequence and analysis plan/use.
1 - Structural T1-weighted: Measure total intracranial volume, grey matter, white matter, cerebrospinal
2 - Angiogram (Time of Flight): Localise the brain vessels to plan the 4D flow
3 - 4D Flow (3D phase contrast (0.75mm isotropic), Velocity encoding=90cm/s): Measure cardiac gated cerebral blood flow in the brain (focused on the circle of Willis)
4 - Functional fMRI: During initial CO2 inhalation, measure the initial response to CO2 bolus as a form of tissue reactivity

Ultrasound Protocol: Scan Time 30 minutes
Immediately following the MRI, an echocardiogram will be performed. This will be undertaken by an experienced echocardiographer using a cardiac ultrasound system. The echocardiogram will be undertaken in the MRI recovery area next to the MRI.
At this stage, and prior to measurement, the option to have a female or male chaperone
will be offered to the participant during the time the researcher is collecting measurements.
Two-dimensional (2D), pulsed-Doppler, and colour tissue Doppler imaging will be performed from standard parasternal and apical transducer positions. All indices will be measured according to the recommendation of the American Society of Echocardiography:
1) Standard 2D left ventricular measurements (apical 4 and 2 chamber volumes) and left atrial size will be recorded. Left ventricular ejection fraction will be quantified using Simpson’s biplane method, left atrial volume will be obtained from Simpson’s biplane volume assessment or area length volume assessment in the apical views. 3D left ventricular volumes will be assessed.
2) Left ventricular diastolic parameters will include the combined mitral inflow and annular tissue Doppler velocities (with sample volume placed at the mitral annulus and the average value of the medial and lateral velocities will be used to derive the E/e’).
3) Left ventricular global longitudinal strain (GLS) will be measured using speckle tracking echocardiography (STE) in the three standard apical views and the average value recorded. If regional tracking is suboptimal in more than two myocardial segments in a single view, the calculation of GLS will be recorded as unobtainable.
4) RV systolic function will be assessed by tricuspid annular plane systolic excursion [TAPSE]. TAPSE is easily obtainable and has been shown to be an accurate reflection of RV global systolic function.
Two 3D+t volumetric scans of one breath-hold each will be acquired to reconstruct 3D cardiac geometry and function within one cardiac cycle. Using echo analysis software, 3D measurements of left ventricular geometry and function such as: left ventricular mass, left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction, as well as 3D myocardial strain, will be derived from the 3D volumetric data. Finally, the raw imaging data will be converted to DICOM images, which will then be analysed using a model-based image processing software tool to construct a 3D computer model of the left ventricle for biomechanical analysis.
Two 3D-doppler images will be taken in the left ventricle and aorta to allow for assessment of quantification of pressure via a non-invasive means. A Pulse Cor R6.5 Cardiovascular monitor will be used to measure aortic pressure and arterial stiffness. This is a standard automated blood pressure cuff and the measurements are no different to having a standard blood pressure measurement performed.

The ultrasound imaging will be repeated breathing the CO2 enriched gas blend for reactivity measurements after free end tidal CO2 has normalised on the gas monitor. Each imaging round with and without gas will last about 15 minutes.

Blood Collection:
The participant and accompanying researcher will travel by foot or cab to the designated blood collection sites. The private third-party company will draw, store, process, and destroy the blood tissue (unless return is requested, an option by the companies named below).

Blood Tests:
Oestradiol (Estrogen) from plasma
Progesterone from plasma.
Haematocrit (red blood cell count, platelet count) from whole blood sample.
Testosterone (Total) from plasma
Intervention code [1] 329107 0
Early detection / Screening
Comparator / control treatment
No control group
Control group
Uncontrolled

Outcomes
Primary outcome [1] 338905 0
Identify strongest cerebrovascular reactivity index in response to hypercapnia by free breathing a carbon dioxide enriched gas blend (5% CO2, 21% O2, and 74% Nitrogen) with correction for covariates (global, cardiac, and hormones).
Timepoint [1] 338905 0
Primary timepoint of most measures (Interaction 3). Also including some information from Interaction 2, collected ~5 days prior to Interaction 3).
Primary outcome [2] 339015 0
Identify metrics that are sex and ethnicity sensitive.
Timepoint [2] 339015 0
Primary timepoint of most measures (Interaction 3). Also including some information from Interaction 2, collected ~5 days prior to Interaction 3).
Secondary outcome [1] 437887 0
Quantify differences in pulse wave velocity measured from carotid femoral arterial tonometry and 3D phase contrast MRI, at rest.
Timepoint [1] 437887 0
Using data from two timepoints interaction 3, and Interaction 2, collected ~5 days prior to Interaction 3).
Secondary outcome [2] 439568 0
Quantify differences in pulse wave velocity reactivities measured from carotid femoral arterial tonometry and 3D phase contrast MRI.
Timepoint [2] 439568 0
Using data from two timepoints interaction 3, and Interaction 2, collected ~5 days prior to Interaction 3).

Eligibility
Key inclusion criteria
Inclusion: NZ European Descent or Maori.
Inclusion: Male or Female at Birth.
Inclusion: Can donate blood (comfortable with needles)
Minimum age
25 Years
Maximum age
35 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Exclusion: MRI contraindications (implants, claustrophobia)
Exclusion: Current or recently quit smoker
Exclusion: Diabetes
Exclusion: Major structural or pathological cardiac, blood, or cerebral abnormalities (e.g.
hypertrophic cardiomyopathy, brain tumors, aneurysms, sickle cell disease, hypertension)
Exclusion: History of alcoholism.

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
10/11/2024
Actual
Date of last participant enrolment
Anticipated
20/11/2024
Actual
Date of last data collection
Anticipated
10/12/2024
Actual
Sample size
Target
20
Accrual to date
Final
Recruitment outside Australia
Country [1] 26454 0
New Zealand
State/province [1] 26454 0

Funding & Sponsors
Funding source category [1] 317021 0
University
Name [1] 317021 0
Auckland Bioengineering Institute research Development Fund
Country [1] 317021 0
New Zealand
Funding source category [2] 317043 0
Charities/Societies/Foundations
Name [2] 317043 0
Maurice and Phyllis Paykel Trust
Country [2] 317043 0
New Zealand
Funding source category [3] 317044 0
Government body
Name [3] 317044 0
Health Research Council of New Zealand Activation Grant
Country [3] 317044 0
New Zealand
Primary sponsor type
University
Name
University of Auckland
Address
Country
New Zealand
Secondary sponsor category [1] 319290 0
None
Name [1] 319290 0
Address [1] 319290 0
Country [1] 319290 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 315777 0
Central Health and Disability Ethics Committee
Ethics committee address [1] 315777 0
https://ethics.health.govt.nz/about/central-health-and-disability-ethics-committee/
Ethics committee country [1] 315777 0
New Zealand
Date submitted for ethics approval [1] 315777 0
04/07/2024
Approval date [1] 315777 0
22/07/2024
Ethics approval number [1] 315777 0
20417

Summary
Brief summary
Our understanding of human physiology is largely driven by data from males of European ethnicities, leading to widespread sex and ethnic differences in the quality of treatment and clinical outcomes. This knowledge profoundly shapes the guidelines and design of diagnosis and treatment, particularly for brain health. Perhaps as a consequence, females are known to have a higher risk of severe dementia and vascular diseases, and Maori have higher mortality from stroke. We are proposing an advanced multicenter imaging study to characterise vascular differences in the brain in equal sex-represented Maori and Pakeha groups. We aim to identify physiological differences between groups related to vascular reactivity and cerebral pulsatility that can translate to more adequate treatments or further emphasise the impact of poorer access to interventions/increases in mortality.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 135762 0
Dr Gonzalo Daniel Maso Talou
Address 135762 0
University of Auckland UniServices House, Level, 6/70 Symonds St , Auckland, 1010
Country 135762 0
New Zealand
Phone 135762 0
+642108468901
Fax 135762 0
Email 135762 0
[email protected]
Contact person for public queries
Name 135763 0
Gonzalo Daniel Maso Talou
Address 135763 0
University of Auckland UniServices House, Level, 6/70 Symonds St , Auckland, 1010
Country 135763 0
New Zealand
Phone 135763 0
+642108468901
Fax 135763 0
Email 135763 0
[email protected]
Contact person for scientific queries
Name 135764 0
Gonzalo Daniel Maso Talou
Address 135764 0
University of Auckland UniServices House, Level, 6/70 Symonds St, Auckland, 1010
Country 135764 0
New Zealand
Phone 135764 0
+642108468901
Fax 135764 0
Email 135764 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
Non-identifiable data derived from MRI and cardiac ultrasound images, tables collating measurements collected from participants, and blood analysis results. All data will be anonymized.
When will data be available (start and end dates)?
Data will be available after the study results have been published, anticipated June 2025, and be available for a period of 10 years, potentially longer if participants agree to extended anonymized storage.
Available to whom?
Any interested researcher associated with a university upon reasonable request. Users agree to acknowledge the original work. A data-sharing agreement will be signed, agreeing not to share the data externally.
Available for what types of analyses?
Any.
How or where can data be obtained?
Data-sharing requests can be made to the Principal Investigator (Gonzalo Daniel Maso Talou, email:[email protected]), who will conduct the data transfer via a web-sharing link.


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
24035Ethical approval    388176-(Uploaded-24-07-2024-16-46-03)-HERStudy_HDEC_Approval.pdf
24036Study protocol    388176-(Uploaded-24-07-2024-16-46-29)-HER_Protocol_v1.3.docx
24037Informed consent form    388176-(Uploaded-24-07-2024-16-46-43)-HER_Consent_Form_v1.2.docx



Results publications and other study-related documents

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No documents have been uploaded by study researchers.

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