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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Venous thromboembolism prevention in lower leg injury requiring immobilisation: a feasibility study and open-label trial of Jet Impulse Technology (JIT) within-cast:

Scientific title
Feasibility study of 18-70 year olds with lower limb injuries requiring below knee immobilisation, utilising Jet Impulse Technology with inflatable footpad with usual care of aspirin EC 100mg daily
Secondary ID [1] 286141 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Venous thromboembolism 294150 0
Lower limb injury requiring cast or moon-boot immobilisation 294151 0
Condition category
Condition code
Blood 294471 294471 0 0
Clotting disorders
Respiratory 294472 294472 0 0
Other respiratory disorders / diseases
Injuries and Accidents 294473 294473 0 0

Study type
Description of intervention(s) / exposure
The Jet Impulse Technology (JIT) system, is supplied by Dickson and Dickson Healthcare (DnD Healthcare) and comprises a VENAjet pump system foot garment.

This is a system that is used regularly for DVT prophylaxis in high risk and immobile patients post-surgery.

The subjects' foot that is intended to be casted will be placed in a foot compression garment (a cuff) that will be attached by tube assembly to a pump unit. When the pump unit is turned on, a distal aircell within the foot cuff will inflate rapidly to approximately 130mmHg +/-10% and will then settle to 52mmHg, and a proximal aircell follows approximately 0.3 seconds after, to settle at approximately 48mmHg. After 6 seconds of compression at 48-53mmHg, the cuffs deflate. The cycle repeats every minute.

The JIT system will be placed on the participants foot, and the cast will be applied over the JIT system.

The JIT system is supposed to be used during non-weight bearing so those using the device will be asked to use it while they are seated or immobile during the day and while in bed at night. Information about device usage will be collected at each visit to determine the use of JIT (60%, or 14.4 hours per day average is defined as good adherence).

In addition to this intervention, participants will receive the usual care of aspirin EC, 100mg daily.

The overall duration of lower limb immobiisation is expected to be a minimum of 4 weeks, out to a maximum of 8 weeks.

At weeks 2 and 4 of enrolment, participants will have an above-cast ultrasound of the casted limb to check for asymptomatic deep vein thrombosis (DVT)

At approximately 8 weeks (after removal of the limb immobilisation), participants will have a full length lower limb ultrasound to check for asymptomatic DVT.
Intervention code [1] 291143 0
Comparator / control treatment
As this is a feasibility study to assess the utilisation and safety of the device and the likelihood of this being a comparator arm in the proposed MAIN RCT, there is no intended comparator group.

All potential participants that present during usual working hours will be offered the opportunity to participate in the study until 70 participants have been recruited. Those that choose not to participate will receive the usual care of 100mg aspirin EC daily. They will not be recruited into the trial and will not be followed up.
Control group

Primary outcome [1] 294254 0
The proportion of eligible participants recruited into the open-label trial of the JIT system .
Timepoint [1] 294254 0
At the point at which 70 participants have been enrolled, (anticipated to be approximately 9 months)
Secondary outcome [1] 312881 0
The number of patients eligible for recruitment in the MAIN RCT from the Wellington Hospital fracture clinic for one year.
Timepoint [1] 312881 0
The point at which 70 participants are enrolled in the trial, (expected to be approximately 9 months). The one year outcome will be extrapolated from the time at which the trial is fully recruited.
Secondary outcome [2] 312882 0
The proportion of participants adhering to use of the JIT system for greater than 60% of each 24 hour period averaged over the days between review
Timepoint [2] 312882 0
From the start of the study until removal of the lower limb immobilisation, to a maximum of 8 weeks per participant.
Secondary outcome [3] 312883 0
Proportion of participants in the open-label trial who have complications specific to use of the JIT system, and the consequent proportion that withdrew due to JIT- related adverse events. This is a composite outcome

Adverse events that will be specifically monitored and recorded over this time are:
1. Participant discomfort / pain on using the device, as described by each participant
2. Skin integrity: - redness, chaffing, masceration, on visual inspection by investigators at each clinic visit
Timepoint [3] 312883 0
From the start of the study until removal of the lower limb immobilisation, to a maximum of 8 weeks per participant.
Secondary outcome [4] 312884 0
Proportion of all participants with asymptomatic DVT detected by ultrasound of the popliteal to femoral vein (accessible above the cast) at weeks 2 and 4
Timepoint [4] 312884 0
At completion of the 70th participant in the trial, expected to be approximately 11 months
Secondary outcome [5] 312885 0
Proportion of all participants with asymptomatic DVT detected by ultrasound of the entire index limb after removal of the lower limb immobilisation (between 6 and 8 weeks in most cases).
Timepoint [5] 312885 0
From the start of the study until removal of the lower limb immobilisation, to a maximum of 8 weeks per participant.
Secondary outcome [6] 312886 0
Proportion of all participants with symptomatic DVT and / or PE, as defined by positive finidng on full length lower limb ultrasound and / or positive ventilation / perfusion scan and / or CT Pulmonary Angiogram (CTPA)
Timepoint [6] 312886 0
From the start of the study until removal of the lower limb immobilisation, to a maximum of 8 weeks per participant.

Key inclusion criteria
Aged between 18 and 70 years with
- ruptured Achilles tendon or
- stable ankle fracture requiring a non-weight bearing cast, or
- ankle fracture with operative fixation and then cast immobilisation, or
- elective operation of the lower limb subsequently requiring cast immobilisation
- Able to provide informed consent
Minimum age
18 Years
Maximum age
70 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. History of previous or current DVT or PE
2. Pregnancy
3. Current active cancer, other than basal cell carcinoma of the skin.
4. Known thrombophilic state
5. Already using anticoagulation
6. Use of low molecular weight heparin or immobility greater than two days prior to enrolment.
7. Any other criteria which at the discretion of the investigator will affect the safety of the participant or the participants ability to comply with the requirements of the study

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
During working hours, investigators – in conjunction with nursing staff at the fracture clinic will identify potentially eligible participants. Subjects will be informed about the open-label trial and asked if they would participate. Those who decline to participate will be asked if this is because the treatment is a device rather than a medication. A log will be kept of potential participants who were treated and discharged outside of working hours and of all potential participants approached during the working day.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
There is no randomisation sequence
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The main analyses will be calculation of 95% confidence intervals for a proportion.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 6646 0
New Zealand
State/province [1] 6646 0

Funding & Sponsors
Funding source category [1] 290716 0
Government body
Name [1] 290716 0
Health Research Council of New Zealand
Address [1] 290716 0
PO Box 5541,
Wellesley Street,
Auckland 1141
Country [1] 290716 0
New Zealand
Primary sponsor type
Medical Research Institute of New Zealand
Private Bag 7902
Wellington 6242
New Zealand
Secondary sponsor category [1] 289404 0
Name [1] 289404 0
Victoria University
Address [1] 289404 0
School of Biological Sciences
Victoria University of Wellington
PO Box 600
Wellington 6140
New Zealand
Country [1] 289404 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 292346 0
NZ Health and Disability Ethics Committee
Ethics committee address [1] 292346 0
C/- MEDSAFE, Level 6, Deloitte House
10 Brandon Street
PO Box 5013
Wellington 6145
Ethics committee country [1] 292346 0
New Zealand
Date submitted for ethics approval [1] 292346 0
Approval date [1] 292346 0
Ethics approval number [1] 292346 0

Brief summary
We intend to undertake a full study (MAIN RCT) consisting of a three-arm parallel groups randomised-controlled trial of low dose aspirin, an intermittent pneumatic compression device commercially known as Jet Impulse Technology (JIT) plus low dose aspirin, or rivaroxaban alone to prevent venous thromboembolism (VTE) secondary to cast immobility for a ruptured Achilles tendon or ankle fracture.

For the proposed MAIN RCT to be viable, we need to establish the capacity to recruit, tolerability of JIT placement under a lower limb cast for a protracted period of time (up to 8 weeks), and adherence to the proposed JIT in-cast regime.

This feasibility trial has been designed to establish the proportion of subjects likely to enrol in the MAIN RCT, the ease of application and acceptability of the JIT system under a cast, possible adverse events with the JIT system, and the proportion of symptomatic VTE events in the population enrolled in the trial.
Trial website
Trial related presentations / publications
Public notes
A manuscript has been prepared to outline the findings of this study, and is currently under review with BMJ Open.
Attachments [1] 302 302 0 0

Principal investigator
Name 54802 0
Dr Irene Braithwaite
Address 54802 0
Medical Research Institute of New Zealand Private Bag 7902 Wellington 6242
Country 54802 0
New Zealand
Phone 54802 0
+64 4 805 0245
Fax 54802 0
Email 54802 0
Contact person for public queries
Name 54803 0
Dr Irene Braithwaite
Address 54803 0
Medical Research Institute of New Zealand Private Bag 7902 Wellington 6242
Country 54803 0
New Zealand
Phone 54803 0
+64 4 805 0245
Fax 54803 0
Email 54803 0
Contact person for scientific queries
Name 54804 0
Dr Irene Braithwaite
Address 54804 0
Medical Research Institute of New Zealand Private Bag 7902 Wellington 6242
Country 54804 0
New Zealand
Phone 54804 0
+64 4 805 0245
Fax 54804 0
Email 54804 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary