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Trial registered on ANZCTR


Registration number
ACTRN12624000393550
Ethics application status
Approved
Date submitted
23/02/2024
Date registered
3/04/2024
Date last updated
3/04/2024
Date data sharing statement initially provided
3/04/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Understanding standing in Postural Orthostatic Tachycardia Syndrome (POTS)
Scientific title
Understanding circulatory control in postural orthostatic tachycardia syndrome
Secondary ID [1] 311442 0
None
Universal Trial Number (UTN)
U1111-1300-3515
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Postural Orthostatic Tachycardia Syndrome 332730 0
Condition category
Condition code
Cardiovascular 329450 329450 0 0
Other cardiovascular diseases

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This is a non-therapeutic mechanistic physiological study.

The study consists of a 1 hour familiarisation and two experimental visits (1.5 hours and 3 hours). Studies will be conducted in Human Cardiorespiratory Physiology Laboratory within the Clinical Research Centre, Faculty of Health and Medical Science, University of Auckland. The following physiological measures will be made in the POTS participant group and matched healthy control group. All assessments will be one-on-one.

Assessments:

Screening visit-
Health Screening Questionnaires (EQ-5D-5L, IPAQ, COMPASS-31, MAPS, Beighton Joint Hypermobility)
Delivered by a trained investigator. Delivered face-to-face.
Delivered once. Takes 10-15 min to complete these forms.

Height, weight, hip and waist circumference
Delivered by a trained investigator. Delivered face-to-face.
Delivered once. Takes 5-10 min to complete this assessment.

Experimental visit 1-
The following tests will each be separated by a ~10 minute break.

Arterial stiffness
Measured by the placement of a pen-shaped probe over arteries at the participants neck, wrist, and ankle. A cuff will be placed around the participants upper thigh that will inflate for a couple of minutes.
Delivered by a trained investigator. Delivered face-to-face.
Delivered once. Takes 10-15 min to complete this assessment.

Flow mediated dilatation
While brachial artery is imaged with ultrasound a cuff around the upper arm will be inflated [for 5 minutes] and then deflated [5 minutes].
Delivered by a trained investigator. Delivered face-to-face.
Delivered once. Takes 10-15 min to complete this assessment.

Venous function
Measured by a cuff placed around the thigh, above the knee and a lightweight elastic band or sensor cuff placed around the widest portion of the calf. The cuff will be inflated for 8 minutes and then slowly deflated over 60 seconds.
Delivered by a trained investigator. Delivered face-to-face.
Delivered once. Takes 10-15 min to complete this assessment.

Experimental visit 2-
The following tests will each be separated by a ~10 minute break.

Slow deep breathing
The participant will be asked to take slow deep breaths for 5 minutes with the guidance of an investigator.
Delivered by a trained investigator. Delivered face-to-face.
Delivered once. Takes 10-15 min to complete this assessment.

Handgrip test
The participant will be asked to hold a device that measures the force of the handgrip. The participant will do some short handgrip trials to establish the maximum grip strength, then hold ~30% of this for 2 min.
Delivered by a trained investigator. Delivered face-to-face.
Delivered once. Takes 10-15 min to complete this assessment.

Valsalva’s manoeuvre
The participant will forcefully breathe out against a resistance (breathing out whilst you are wearing a mouthpiece) for around 15 seconds.
Delivered by a trained investigator. Delivered face-to-face.
Delivered three times. Takes 5-10 min to complete this assessment.

Cold pressor test
The participant will be asked to place a hand in cold water for 2 minutes.
Delivered by a trained investigator. Delivered face-to-face.
Delivered three times. Takes 5-10 min to complete this assessment.

The devices/instruments used for study visits are novel devices supplied for human research purposes (e.g., by ADInstruments).
Intervention code [1] 328055 0
Early detection / Screening
Comparator / control treatment
Age and biological-sex matched healthy participants
Control group
Active

Outcomes
Primary outcome [1] 337490 0
Arterial stiffness
Timepoint [1] 337490 0
Assessed once at a single time-point (Experimental visit 1)
Primary outcome [2] 337491 0
Endothelial function
Timepoint [2] 337491 0
Assessed once at a single time-point (Experimental visit 1)
Primary outcome [3] 337762 0
Venous function
Timepoint [3] 337762 0
Assessed once at a single time-point (Experimental visit 2)
Secondary outcome [1] 432086 0
Heart rate
Timepoint [1] 432086 0
Assessed continuously for ~2 hours during Experimental visit 2
Secondary outcome [2] 432087 0
Blood pressure
Timepoint [2] 432087 0
Assessed continuously for ~2 hours during Experimental visit 2
Secondary outcome [3] 432088 0
Muscle sympathetic nerve activity
Timepoint [3] 432088 0
Assessed continuously for ~2 hours during Experimental visit 2

Eligibility
Key inclusion criteria
• Participants with a clinical diagnosis of POTS
• Healthy volunteers with no history of POTS
• Men and women
• Aged 18 years and over
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
• Severe cardiac disease (e.g., coronary artery disease, heart failure, hypertension)
• Primary / secondary autonomic dysfunction
• Significant arrhythmias (e.g., atrial fibrillation, previous VT / significant ventricular ectopy)
• Severe respiratory disease (e.g., chronic obstructive pulmonary disease)
• Severe, uncontrolled type II diabetes
• Significant renal or liver disease
• Significant neurological disease including diabetic neuropathy
• Current active treatment for cancer
• Inflammatory disease
• Infection or pyrexial illness
• Uncontrolled thyroid disorders
• Recent (< 3 months) ischemic stroke
• Current smoker/vaper
• Current pregnancy
• Users of recreational drugs
• Current hazardous alcohol use. Participant’s alcohol intake will be initially screened in the Health Screening Questionnaire. If alcohol intake exceeds recommended limits, then the participant will be assessed by AUDIT questionnaire for hazardous alcohol intake (score of 8 or more on AUDIT).
• Inability to fully or appropriately provide consent (e.g., language issue, reading capability)
• Underlying medical conditions, which in the opinion of the Investigator place the participant at unacceptably high risk for participating in the study

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
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
Anthropometric (e.g., BMI) and demographic (e.g., age) information gathered at primary screening will be quantified using basic statistics (mean, SD, Median, IQR) and graphical presentations (boxplots, histograms, scatter plots). Likewise, levels of primary and secondary outcomes will be similarly reported. Responses will be compared in normotensive and hypertensive individuals. Normal distribution will be evaluated using Shapiro-Wilk tests. Comparisons of normally distributed physiological variables for a given trial will be made using a t-test, and non-normally distributed data evaluated using a Mann–Whitney U test. In the event of potential confounding differences in baseline characteristics (e.g., physical activity), analysis of covariance (ANCOVA) will be employed. Statistical analysis will be performed using SPSS (IBM Corp.,). Significance will be set at p < 0.05. Normally distributed data will be presented as mean (SD) while non-normally distributed data will be presented as median [interquartile range].

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
16/04/2024
Actual
Date of last participant enrolment
Anticipated
4/03/2027
Actual
Date of last data collection
Anticipated
4/03/2027
Actual
Sample size
Target
50
Accrual to date
Final
Recruitment outside Australia
Country [1] 26129 0
New Zealand
State/province [1] 26129 0

Funding & Sponsors
Funding source category [1] 315719 0
University
Name [1] 315719 0
University of Auckland
Country [1] 315719 0
New Zealand
Primary sponsor type
University
Name
University of Auckland
Address
Country
New Zealand
Secondary sponsor category [1] 318055 0
None
Name [1] 318055 0
Address [1] 318055 0
Country [1] 318055 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 314583 0
Central Health and Disability Ethics Committee
Ethics committee address [1] 314583 0
Ministry of Health, 133 Molesworth Street, PO Box 5013, Wellington, 6011
Ethics committee country [1] 314583 0
New Zealand
Date submitted for ethics approval [1] 314583 0
23/11/2023
Approval date [1] 314583 0
18/12/2023
Ethics approval number [1] 314583 0

Summary
Brief summary
Individuals with POTS often experience blood pooling in the legs, which is thought to occur because of abnormal tightening of the blood vessels on standing. However, the mechanism underlying this is remains unclear. The aim of this project is to investigate the blood vessel structure (specifically how stretchy the blood vessels are), function (how well the blood vessels tighten), and regulation (how well the nerves tighten the blood vessels) in people with POTS and people without POTS. The data will also be used to make computer models of the cardiovascular system to better understand mechanisms of individuals with POTS. It is hoped that our work will provide insight to the mechanisms underlying POTS which may help improve and personalise treatments for patients.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 132086 0
A/Prof James P Fisher
Address 132086 0
Matauranga Hauora | Faculty of Medical and Health Sciences Waipapa Taumata Rau | The University of Auckland Room 503-401C, Bldg 503, 85 Park Road, Grafton, Auckland 1023
Country 132086 0
New Zealand
Phone 132086 0
+64 9 9236320
Fax 132086 0
Email 132086 0
jp.fisher@auckland.ac.nz
Contact person for public queries
Name 132087 0
James P Fisher
Address 132087 0
Matauranga Hauora | Faculty of Medical and Health Sciences Waipapa Taumata Rau | The University of Auckland Room 503-401C, Bldg 503, 85 Park Road, Grafton, Auckland 1023
Country 132087 0
New Zealand
Phone 132087 0
+64 9 9236320
Fax 132087 0
Email 132087 0
jp.fisher@auckland.ac.nz
Contact person for scientific queries
Name 132088 0
James P Fisher
Address 132088 0
Matauranga Hauora | Faculty of Medical and Health Sciences Waipapa Taumata Rau | The University of Auckland Room 503-401C, Bldg 503, 85 Park Road, Grafton, Auckland 1023
Country 132088 0
New Zealand
Phone 132088 0
+64 9 9236320
Fax 132088 0
Email 132088 0
jp.fisher@auckland.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.