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Trial registered on ANZCTR

Registration number

ACTRN12611001003965

Ethics application status

Approved

Date submitted

19/09/2011

Date registered

20/09/2011

Date last updated

20/09/2011

Type of registration

Retrospectively registered

Titles & IDs

Public title

The average level of blood thinning, resulting from an individual weight determined dose of Clexane, when given to women after caesarian section to prevent blood clots.

Scientific title

The effect of a weight-based enoxaparin thromboprophylaxis on antiXa levels in women post caesarian section.

Secondary ID [1]

Nil

Universal Trial Number (UTN)

U1111-1124-5054

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

thromboprophylaxis for caesarian section

Condition category

Condition code

Blood

Clotting disorders

Reproductive Health and Childbirth

Childbirth and postnatal care

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Enoxaparin dose is based upon patient weight at time of confinement booking (usually 6 - 12 weeks gestation)
Dosage schedule is:

Less than 40 kg 20 IU subcutaneous daily
> 40 to 90kg 40 IU subcutaneous daily
> 90 to 130 kg 60 IU subcutaneous daily
> 130 to 170 kg 80 IU subcutaneous daily
> 170 kg 0.5 IU/kg subcutaneous twice daily

Administered day 1,2 and 3 post partum

Intervention code [1]

Treatment: Drugs

Intervention code [2]

Prevention

Comparator / control treatment

NIL

Control group

Uncontrolled

Outcomes

Primary outcome [1]

plasma AntiXa levels

Timepoint [1]

baseline, 4 hours post first & third doses

Secondary outcome [1]

Nil

Timepoint [1]

Nil

Eligibility

Key inclusion criteria

post caesarian section.
patient classified as high or intermediate risk of VTE based upon BCOG guidelines 2009

Minimum age

No limit

Maximum age

No limit

Sex

Females

Can healthy volunteers participate?

Key exclusion criteria

refusal to enter trial
no booking maternal weight obtainable

Study design

Purpose of the study

Prevention

Allocation to intervention

Non-randomised trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

convenience sampling to fill weight based strata

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

N/A

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Single group

Other design features

Phase

Phase 4

Type of endpoint/s

Pharmacokinetics

Statistical methods / analysis

Recruitment

Recruitment status

Recruiting

Date of first participant enrolment

Anticipated

19/09/2011

Actual

Date of last participant enrolment

Anticipated

Actual

Date of last data collection

Anticipated

Actual

Sample size

Target

160

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Funding & Sponsors

Funding source category [1]

Hospital

Name [1]

Mercy Hospital For Women

Address [1]

163 Studley Road
Heidelberg Victoria 3084

Country [1]

Australia

Primary sponsor type

Hospital

Name

Mercy Hospital For Women

Address

163 Studley Road
Heidelberg Victoria 3084

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Ethics committee address [1]

Ethics committee country [1]

Date submitted for ethics approval [1]

Approval date [1]

Ethics approval number [1]

R11/35

Summary

Brief summary

Following major surgery patients are at increased risk of developing blood clots in the veins of the lower limb and in some patients these may dislodge, travel to the lung as pulmonary emboli, resulting in breathing difficulties and rarely death. The situation is no different after caesarian section, where patients are at increased risk of blood clots, however the risk is not the same for all but influenced by factors such as previous history of blood clots, the need for emergency surgery, age and body weight. 
After your surgery we can minimize the risk of blood clots by mobilizing you as soon as possible, using below knee compression stockings, which prevent pooling of blood in calf veins and in certain patients by once daily injections under the skin of a blood thinning low molecular weight heparin drug (LMWH) called enoxaparin. For many years the dose of enoxaparin has been fixed and not adjusted for body weight, however there is evidence from studies in overweight non-pregnant patients that as body weight increases an increase in dose is required to maintain prevention. Pregnancy also alters the way these enoxaparin is handled by the body resulting in an increase in the dose required (at the end of pregnancy and immediately after delivery) to provide the same action as in the non-pregnant patient. 
Recently, the Royal College of Obstetrician and Gynaecologists (RCOG) in the United Kingdom have updated their guidelines for prevention of thrombosis after caesarian section and recommend that patients classified as intermediate risk or greater should be given LMWH with the dose determined by their actual body weight at 8 -16 weeks of gestation (usually referred to as the booking weight). 

We believe that you fall into the intermediate (or high) risk category and therefore would benefit from having LMWH preventative treatment. The dose given to you will be that recommended by the RCOG guideline and will be calculated based on your body weight at the time of registering for care at the Mercy Hospital for Women. For patients of less than 90 kg you will receive what for many years has been the standard dose of enoxaparin. For patients above 90 kg you will receive a dose greater than this fixed dose, which we believe is safe and is likely to result in better prevention of clots compared to the usual dose. 
We are asking that you consent to having three samples of blood (10 mls each) taken and analyzed for LMWH blood thinning activity (antiXa levels). The first and second samples will be taken immediately prior to & then four hours after your first preventative injection some 4-12 hours after completion of your caesarian section. A third sample will be taken four hours after your third or fourth dose given on the day prior to your discharge from hospital. An additional small plastic cannula will be inserted into a arm vein at the time of your caesarian section and the first blood sample taken at that time. A second sample, hopefully via the cannula, will be taken 3 – 5 hours after the injection of Enoxaparin some 4-12 hours after your caesarian delivery. The third sample will require a separate blood test to be taken. 
The study does not change the obstetric or anaesthetic management of your delivery.  Breast feeding is considered safe whilst on enoxaparin. 
All blood thinners lead to a slightly increased risk of wound and uterine bleeding.  We don't believe that the risk of bleeding is increased over that seen in non pregnant patients given enoxaparin to prevent blood clots following surgery.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Address

Country

Phone

Fax

Contact person for public queries

Name

Clin Assoc Prof Scott Simmons

Address

Mercy Hospital for Women
163 Studley Road
Heidelberg Victoria 3084

Country

Australia

Phone

61 0384584113

Fax

[email protected]

Contact person for scientific queries

Name

Clin Assoc Prof Scott Simmons

Address

Department of Anaesthesia
Mercy Hospital for Women
163 Studley Road
Heidelberg Victoria 3084

Country

Australia

Phone

61 03 84584113

Fax

[email protected]

No information has been provided regarding IPD availability

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.

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