Clinical Trials Logo

Clinical Trial Summary

Venous thromboembolism (VTE) remains the most common cause of maternal death in the developed world. VTE includes two conditions, deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT refers to a blood clot that has formed in a deep vein, often in the legs and/or pelvis and PE refers to the passage of these clots into the lungs (which can be fatal). VTE is up to 10 times more common in pregnant women than non-pregnant women of comparable age. More than a third of pregnancy related VTE occur during the 6 weeks after delivery. When compared with vaginal delivery, cesarean delivery further increases the risk of pregnancy associated VTE by three-fold.

A medication called low molecular weight heparin is sometimes prescribed during pregnancy and after delivery to prevent VTE. However, clinical practice varies because there hasn't been adequate research to determine that this medication is safe and effective at preventing VTE during this time. The potential benefits of the medication must also be weighed against its cost and possible side effects.

The researchers are conducting a study that will assess the effectiveness and safety of low molecular weight heparin in women who are at moderate to high risk of VTE after a cesarean section. They will monitor these women to determine if those who received the medication have fewer blood clots. Participants will also be monitored closely for any side effects.


Clinical Trial Description

BACKGROUND: Venous thromboembolism (VTE) remains the most common cause of maternal mortality in the developed world. VTE is up to 10 times more common in pregnant women than non-pregnant women of comparable age. More than a third of pregnancy related VTE occur during the brief postpartum period (6 weeks). When compared with vaginal delivery, cesarean delivery further increases the risk of pregnancy associated VTE by three-fold. Pregnancy associated VTE is unique in that isolated iliac vein thrombosis is more likely and long term morbidity (post-phlebitic syndrome) is common.

There is an absence of randomized controlled trials (RCTs) of thromboprophylaxis after C-section to guide practice. Many national societies have guidelines on thromboprophylaxis however these are not evidence based and compliance with these guidelines is poor. Thromboprophylaxis may be associated with adverse effects (bleeding, heparin induced thrombocytopenia, skin reactions), inconvenience and cost. It is critical that the efficacy and safety of thromboprophylaxis following cesarean delivery be assessed in well designed and conducted randomized trials.

OBJECTIVES: We are conducting a randomized double-blind placebo-controlled pilot study. The pilot study seeks to answer the question: Is a randomized double-blind placebo-controlled multicentre trial of low molecular weight heparin thromboprophylaxis feasible in moderate to high risk women post cesarean section with DVT detected by pelvic vein (MRV) or leg vein (leg compression ultrasound) imaging? Our ultimate goal is to determine:

1. Is LMWH effective in preventing postpartum DVT following cesarean section in women at moderate to high risk of VTE?

2. Is LMWH safe in preventing postpartum DVT following cesarean section in women at moderate to high risk of VTE?

3. Is LMWH cost effective in preventing postpartum DVT following cesarean section in women at moderate to high risk of VTE?

STUDY DESIGN: We propose a randomized double-blind placebo-controlled pilot study of prophylactic LMWH in women at moderate to high risk for VTE following cesarean section. Eligible, consenting and randomized participants will receive once-daily injections of study drug (4,500 IU tinzaparin sodium (Innohep®;) or placebo) within 6 to 24 hours postpartum and continue until 3 to 7 days postpartum. On the day of hospital discharge, bilateral leg imaging with compression leg ultrasounds and pelvic vein imaging with MRV will be completed. The primary outcome will be adjudicated DVT documented on ultrasounds or MRV on the day of hospital discharge. Secondary outcomes will include symptomatic DVT and PE, death from PE, major and minor bleeding, HIT during the six week postpartum period. All outcomes will be adjudicated by an independent committee of experts blinded to study drug allocation.

With a sample size of 134 patients we will have over 80% power to detect a 50% relative risk reduction in the primary outcome event rate and a large enough sample to determine the feasibility objectives of the pilot study (i.e. obtain a precise estimate of the primary outcome event rate [DVT], a precise estimate of the multicentre recruitment rate, feasibility and acceptability of blinded study drug and placebo administration, feasibility of obtaining local study centre MRV and central interpretation of MRV and a preliminary relative risk reduction estimate with study drug compared to placebo to inform final study sample size determination).

RELEVANCE: Maternal mortality is a devastating outcome with far reaching emotional and societal implications. Evidence to guide thromboprophylaxis in women at risk for the number 1 cause of maternal mortality is required. ;


Study Design


Related Conditions & MeSH terms


NCT number NCT00225108
Study type Interventional
Source Ottawa Hospital Research Institute
Contact
Status Completed
Phase Phase 2/Phase 3
Start date July 2002
Completion date September 2006

See also
  Status Clinical Trial Phase
Recruiting NCT05003843 - BOLT: Study of the Indigo® Aspiration System When Used in Patients With Deep Vein Thrombosis N/A
Recruiting NCT03937947 - Traumatic Brain Injury Associated Radiological DVT Incidence and Significance Study
Withdrawn NCT04136561 - Novel Strategy to Encourage Early Removal of Central Venous Catheters N/A
Completed NCT03420625 - Blood Flow Stimulation in the Lower Limbs by Application of Different External Devices N/A
Recruiting NCT02507180 - Safely Ruling Out Deep Vein Thrombosis in Pregnancy With the LEFt Clinical Decision Rule and D-Dimer
Completed NCT02555111 - Xarelto Versus no Treatment for the Prevention of Recurrent Thrombosis in Patients With Chronic Portal Vein Thrombosis. Phase 3
Terminated NCT02469376 - Evaluation of a New Imagingtechnologie for Thrombosis Phase 1
Completed NCT01975090 - The SENTRY Clinical Study N/A
Completed NCT02037607 - Incidence of Venous Thromboembolism in Children Undergoing Elective Neurosurgical Procedures N/A
Not yet recruiting NCT01357941 - Need for Antepartum Thromboprophylaxis in Pregnant Women With One Prior Episode of Venous Thromboembolism (VTE) N/A
Completed NCT00771303 - Ruling Out Pulmonary Embolism During Pregnancy:a Multicenter Outcome Study
Completed NCT00720915 - D-dimer to Select Patients With First Unprovoked Venous Thromboembolism Who Can Have Anticoagulants Stopped at 3 Months N/A
Completed NCT00773448 - Screening for Occult Malignancy in Patients With Idiopathic Venous Thromboembolism N/A
Completed NCT00244725 - Odiparcil For The Prevention Of Venous Thromboembolism Phase 2
Completed NCT00264277 - D-dimer to Establish Duration of Anticoagulation After Venous Thromboembolism Phase 4
Completed NCT00365950 - 3 Months' Versus 6 Months' Anticoagulation in Patients With DVT and/or PE Phase 4
Completed NCT00182403 - Fixed Dose Heparin Study Phase 3
Completed NCT03682419 - Evaluation of Precision and Accuracy of INR Measurements in a Point of Care Device (OPTIMAL) N/A
Not yet recruiting NCT04981327 - The API-CALF Study: Apixaban to Treat Calf Vein Thrombosis Phase 3
Recruiting NCT03240120 - A Study of Dabigatran Etexilate as Primary Treatment of Malignancy Associated Venous Thromboembolism Phase 3