Need for Antepartum Thromboprophylaxis in Pregnant Women With One Prior Episode of Venous Thromboembolism (VTE)

• Conditions: Venous Thromboembolism; Deep Vein Thrombosis; Pulmonary Embolism

• Registration Number: NCT01357941
• Lead Sponsor: Hamilton Health Sciences Corporation

Brief Summary

Pregnant women with a prior history of venous thromboembolism (VTE) are at increased risk of recurrent VTE. Current guidelines assessing the role of prophylaxis in pregnant women with prior VTE are based primarily on expert opinion and the optimal clinical management strategy remains unclear.

This multicentre, prospective cohort study aims to test the following hypotheses:

1. Antepartum prophylaxis with fixed-dose low molecular-weight heparin (LMWH) is safe, convenient and associated with an acceptably low risk of recurrent VTE in women with a single prior episode of VTE that was either unprovoked or associated with a minor transient risk factor. (Moderate risk cohort)

2. Withholding antepartum prophylaxis is safe (recurrence risk \<1%) in pregnant women with a single prior episode of VTE provoked by a major transient risk factor. (Low risk cohort)

All study patients will receive 6 weeks of postpartum prophylaxis.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2011-05-19
• Study First Submitted QC: 2011-05-20
• Study First Posted: 2011-05-23
• Status Verified: 2011-06
• Last Update Submitted: 2011-06-02
• Last Update Posted: 2011-06-03
• Study Start: 2011-09
• Primary Completion: 2013-09
• Study Completion: 2014-09

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: Female
• Target Recruitment: 203

Inclusion Criteria

• Confirmed pregnancy (positive serum or urine)
• At least 18 years of age
• History of one prior episode of VTE consisting of DVT (diagnosed by compression ultrasonography [CUS] or venography) and/or PE (diagnosed by ventilation-perfusion [V/Q] lung scintigraphy, computed tomographic pulmonary angiography [CTPA], or traditional pulmonary angiography)

Exclusion Criteria

• Ongoing need for therapeutic anticoagulation for prevention or treatment of cardioembolic stroke
• Known high-risk thrombophilia (specifically antithrombin deficiency, protein S deficiency, protein C deficiency, homozygosity for the factor V Leiden or prothrombin G20210A mutations, antiphospholipid antibody or compound abnormalities)
• VTE within 3 months of the current pregnancy
• Clinical risk factor for initial episode of VTE, if present, not resolved (excluding pregnancy)
• Known contraindication to anticoagulation (including active, uncontrolled bleeding or major bleed within the previous 4 weeks)
• For patients with prior unprovoked VTE, contraindication to LMWH (including allergy, HIT, impaired renal function, osteoporosis)
• Geographic or social factors precluding follow-up
• Inability or unwillingness to provide informed consent

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Symptomatic venous thromboembolism	antepartum period (expected average 7 months)	Symptomatic objectively confirmed recurrent VTE, including proximal DVT, non-fatal PE, and fatal PE during antepartum period

Secondary Outcome Measures

Name	Time	Method
Thrombocytopenia or heparin-induced thrombocytopenia (HIT)	antepartum period (expected average 7 months)	Thrombocytopenia or HIT during antepartum period
Symptomatic recurrent venous thromboembolism	antepartum period (expected average 7 months) and first 3 months postpartum	Symptomatic recurrent VTE antepartum and within first 3 months postpartum
Symptomatic recurrent pulmonary embolism	antepartum period (expected average 7 months) and first 3 months postpartum	Symptomatic objectively confirmed recurrent PE antepartum and within first 3 months postpartum
Symptomatic osteoporosis	antepartum period (expected average 7 months) and first 3 months postpartum	Symptomatic osteoporosis antepartum and within first 3 months postpartum
Other complications	antepartum (expected average 7 months) and within first 3 months postpartum	Other complications sufficient to stop treatment (e.g., local and systemic reactions) antepartum and within first 3 months postpartum
Pregnancy complications and outcomes	antepartum period (expected average 7 months)	Pregnancy complications and outcomes including fetal death, pre-eclampsia, toxemia, intrauterine growth restriction, prematurity during antepartum period
Fetal anomalies	antepartum (expected average 7 months) and during first 3 months postpartum	Fetal anomalies
Major and minor bleeding	antepartum (expected average 7 months)	Major and minor bleeding

Trial Locations

Locations (2)

McMaster University Medical Centre; 🇨🇦 Hamilton, Ontario, Canada

St. Joseph's Healthcare Hamilton; 🇨🇦 Hamilton, Ontario, Canada