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Trial registered on ANZCTR


Registration number
ACTRN12615000418572
Ethics application status
Approved
Date submitted
31/03/2015
Date registered
1/05/2015
Date last updated
23/01/2020
Date data sharing statement initially provided
23/01/2020
Date results provided
23/01/2020
Type of registration
Retrospectively registered

Titles & IDs
Public title
Assessment of Cerebrovascular Function in Patients with previous Aortic Coarctation Repair
Scientific title
A cross sectional study to examine cerebrovascular function in patients with previous surgical relief of aortic coarctation using transcranial Doppler ultrasound.
Secondary ID [1] 286456 0
Nil
Universal Trial Number (UTN)
U1111-1168-8983
Trial acronym
Aortic Coarctation study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Aortic Coarctation - congenital heart disease 294637 0
Condition category
Condition code
Cardiovascular 294936 294936 0 0
Other cardiovascular diseases

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
We will evaluate the nature of cerebral blood flow using transcranial Doppler ultrasound (TCD) as well as detect any abnormalities in the larger cerebral arteries in patients with previous surgical relief of aortic coarctation compared with healthy controls.

The procedure will take up to 60 minutes and will be performed by Dr Rachel Wong, the study coordinator, in week one. There is only one visit in this study.

TCD will be used to record mean blood flow velocities during quiet seated rest and during 180 sec of hypercapnia. The cerebrovascular responsiveness to hypercapnia will be calculated as a percentage difference between the resting blood flow velocity and the peak velocity obtained during the hypercapnia. We will then compare the differences in responsiveness between patients and controls.
Intervention code [1] 291537 0
Not applicable
Comparator / control treatment
No treatment, observation only.
Control subjects will be age and gender matched to the participants with previous coarctation repair. They will be healthy, with no history of heart disease.
Control group
Uncontrolled

Outcomes
Primary outcome [1] 294693 0
Cerebrovascular responsiveness (CVR) to hypercapnia at the level of the middle cerebral artery (MCA).

Increases in blood flow velocity in the MCA. Basal cerebral blood flow velocities for 10 cardiac cycles will first be recorded to determine the blood flow velocity (peak systolic, end diastolic and mean) at rest. The measures of cerebral pulsatility and resistive indexes will also be recorded simultaneously. During CVR to hypercapnia, participants breathe carbogen (5% CO2, 95% O2) for 150 seconds and the peak increase of blood flow velocity is recorded. This procedure is done in triplicates with a resting interval of at least 2min between each recording.
Timepoint [1] 294693 0
Week 1, one visit only.
Secondary outcome [1] 313870 0
CVR to hypercapnia at the level of the posterior cerebral artery (PCA)

Increases in blood flow velocity in the PCA. Basal cerebral blood flow velocities for 10 cardiac cycles will first be recorded to determine the blood flow velocity (peak systolic, end diastolic and mean) at rest. The measures of cerebral pulsatility and resistive indexes will also be recorded simultaneously. During CVR to hypercapnia, participants breathe carbogen (5% CO2, 95% O2) for 150 seconds and the peak increase of blood flow velocity is recorded. This procedure is done in triplicates with a resting interval of at least 2min between each recording.
Timepoint [1] 313870 0
Week 1, one visit only.
Secondary outcome [2] 313871 0
CVR to photic stimulation

Cerebrovascular responsiveness (CVR) to photic stimulation will be assessed using transcranial doppler ultrasound. Increase in blood flow velocity in the posterior cerebral arteries (PCA) in response to photic stimulation is a robust activation paradigm that allows for the assessment of the relationship between local neuronal activities and regional blood flow in the cortex (neurovascular coupling capacity) (20). Protocol will take place in a quiet, dark room and a computer monitor will be placed 0.3m in front of the seated participant. The screen will occupy approximately 80% of the participant’s visual field. Mean blood flow velocities in the PCA will be recorded continuously during stimulation period.

After a baseline recording of 1 min eyes open and 1 min eyes closed, CVR to photic stimulation protocol will consist of alternating between 60s eyes closed and 40s eyes open whilst (a) looking at the monitor with a white lighted and (b) looking at an image of complex scenery. Transition between eyes open and close will be signal by an acoustic tone. Previous literature found that the blood flow velocity in the PCA will peak within 20s of photic stimulation. Discarding the first 5 s during the eyes closed, an averaged velocity of the reminding 30s will be the baseline. The vasomotor reaction time will be recorded as the time taken to reach peak velocity after opening eyes. CVR to photic stimulation will be calculated as the percentage increase of peak velocity over baseline velocity.
Timepoint [2] 313871 0
Week 1, one visit only.
Secondary outcome [3] 313872 0
Cerebral artery pulsatility index (PI)

Resting cerebral blood flow pulsatility index of the MCA (peak systolic flow minus end-diastolic flow/mean blood flow velocity) will be determined during the basal blood flow recordings.
Timepoint [3] 313872 0
Week 1, one visit only.
Secondary outcome [4] 313873 0
Systemic arterial compliance (AC)

Seated BP and AC will be assessed after resting in a seated position for 10 min. Four consecutive BP, HR and AC readings were taken at 5-minute intervals by automated oscillometry using a standard BP cuff over the left brachial artery (to assess BP) and tonometer (for pulse wave analysis) positioned perpendicularly over the right radial artery with a sensitivity of at least 18% (to assess large and small artery elasticity indexes) using a Cardiovascular Profiler (HDI Cardiovascular Profiler CR2000).
Timepoint [4] 313873 0
Week 1, one visit only.

Eligibility
Key inclusion criteria
Adult patients having undergone previous surgical repair of aortic coarctation in childhood, having measurable ultrasound signal on both sides of the head. Control participants should be healthy and without heart disease.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Unable to obtain a measurable signal in both left and right MCA.
History of cerebrovascular events including transient ischemic attack.
Uncontrolled hypertension (>160/100mmHg) (measured at the visit to CNRC).
Smokers or those currently on nicotine therapy.

Study design
Purpose
Screening
Duration
Cross-sectional
Selection
Defined population
Timing
Retrospective
Statistical methods / analysis
Participant characteristics (body mass index, waist circumference, clinic BP, medication use, age at time of surgery, type of aortic coarctation intervention, mean 24 hour blood pressure as assessed by ambulatory blood pressure monitoring, if available, history of repeat aortic intervention, history of sleep apnoea, prior stroke or myocardial infarction) will be used as covariates. Age and gender may be added as covariates if they are significantly correlated with the outcome measures. Echocardiography and cross sectional imaging (CT/MRI aorta), where available, will be assessed.

Participant characteristics will be used as covariates if they are significantly correlated with the outcome measures. A two-sample t-test will be used to compare the group differences in outcome measures. Where appropriate, Bonferroni adjustments will be made to allow for multiple comparisons.

As this is a pilot cross-sectional investigation, we will recruit 12 to 15 patients and age and gender match them with healthy controls.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
10/04/2015
Actual
10/04/2015
Date of last participant enrolment
Anticipated
Actual
2/02/2016
Date of last data collection
Anticipated
Actual
2/02/2016
Sample size
Target
30
Accrual to date
Final
27
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 3624 0
John Hunter Hospital Royal Newcastle Centre - New Lambton
Recruitment postcode(s) [1] 9477 0
2305 - New Lambton Heights

Funding & Sponsors
Funding source category [1] 291024 0
Hospital
Name [1] 291024 0
Cardiology Trust Fund
John Hunter Hospital
Country [1] 291024 0
Australia
Primary sponsor type
Hospital
Name
John Hunter Hospital
Address
Lookout Road
New Lambton NSW 2305
Country
Australia
Secondary sponsor category [1] 289703 0
None
Name [1] 289703 0
Address [1] 289703 0
Country [1] 289703 0
Other collaborator category [1] 278420 0
University
Name [1] 278420 0
University of Newcastle
Address [1] 278420 0
University Drive
Callaghan NSW 2308
Country [1] 278420 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 292606 0
Hunter New England Human Research Ethics Committee
Ethics committee address [1] 292606 0
Ethics committee country [1] 292606 0
Australia
Date submitted for ethics approval [1] 292606 0
Approval date [1] 292606 0
09/09/2014
Ethics approval number [1] 292606 0
14/08/20/4.04
Ethics committee name [2] 292607 0
University of Newcastle Human Research Ethics Committee
Ethics committee address [2] 292607 0
Ethics committee country [2] 292607 0
Australia
Date submitted for ethics approval [2] 292607 0
Approval date [2] 292607 0
23/09/2014
Ethics approval number [2] 292607 0
H-2014-0311

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 56206 0
Dr Nicholas Collins
Address 56206 0
Staff Specialist Cardiologist
John Hunter Hospital
c/- 58 Cleary Street
Hamilton NSW 2303, Australia
Country 56206 0
Australia
Phone 56206 0
+61 0411 987 025
Fax 56206 0
Email 56206 0
[email protected]
Contact person for public queries
Name 56207 0
Rachel Wong
Address 56207 0
Clinical Nutrition Research Centre
University of Newcastle
School of Biomedical Sciences & Pharmacy
Medical Sciences Building, MS 514
Callaghan, NSW 2308
Country 56207 0
Australia
Phone 56207 0
+61 02 4921 6408
Fax 56207 0
Email 56207 0
[email protected]
Contact person for scientific queries
Name 56208 0
Nicholas Collins
Address 56208 0
Staff Specialist Cardiologist
John Hunter Hospital
c/- 58 Cleary Street
Hamilton NSW 2303, Australia
Country 56208 0
Australia
Phone 56208 0
+61 0411 987 025
Fax 56208 0
Email 56208 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
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.