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Two Weeks of Low Molecular Weight Heparin for Distal Vein Thrombosis (TWISTER)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT01252420
Recruitment Status : Unknown
Verified July 2010 by Monash Medical Centre.
Recruitment status was:  Recruiting
First Posted : December 3, 2010
Last Update Posted : December 6, 2010
Information provided by:

Study Description
Brief Summary:
The purpose of this study is to determine whether a limited duration of treatment (two weeks of low molecular weight treatment) is a safe and effective treatment for distal deep vein thrombosis of the lower limb.

Condition or disease Intervention/treatment Phase
Venous Thrombosis Pulmonary Embolism Drug: Enoxaparin Phase 4

Detailed Description:

Approximately 50% of symptomatic episodes of deep vein thrombosis (DVT) will be confined to the calf veins (distal DVT). The proportion of distal DVT that propagate to the proximal veins, increasing the risk of pulmonary embolism, is not known. The best treatment of isolated distal DVT is therefore controversial and options include no treatment, follow-up scanning and treatment of only those patients with thrombus propagating to proximal veins, and full anticoagulation for periods ranging from 2 weeks to 3 months.

There is good evidence that the 3-month thromboembolic risk in patients with a negative CUS that is limited to the proximal veins is low, in the order of 1%. Previous studies have demonstrated that patients treated with a short period of anticoagulation (4-6 weeks) have a low risk of developing recurrent DVT or PE. In addition, the specificity of CUS for distal DVT is lower than that for proximal DVT, increasing the proportion of false positive findings, making it likely that a proportion of patients diagnosed with distal DVT are treated unnecessarily, with the attendant risks of major and fatal haemorrhage.

The need for anticoagulation of patients with distal DVT to prevent recurrent DVT is therefore uncertain, however a survey of current practice suggested that most patients with this condition currently receive antithrombotic therapy. The impact of anticoagulation on initial patient symptoms, and the subsequent risk of the post-thrombotic syndrome are also unclear, and may be a possible alternative justification for antithrombotic therapy.

In this proposed multicentre, prospective, cohort study, we plan to determine if a shorter duration of anticoagulation (minimum 2 weeks) is a safe and effective treatment for isolated distal vein thrombosis.

Study Design

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 330 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Two Weeks of Low Molecular Weight Heparin for Distal Vein Thrombosis (TWISTER)
Study Start Date : November 2010
Estimated Primary Completion Date : November 2013
Estimated Study Completion Date : November 2014

Resource links provided by the National Library of Medicine

Drug Information available for: Heparin
U.S. FDA Resources

Arms and Interventions

Intervention Details:
    Drug: Enoxaparin
    1.5mg/kg daily for 2 weeks
    Other Name: Clexane

Outcome Measures

Primary Outcome Measures :
  1. Symptomatic recurrence of venous thrombosis (DVT, non fatal and fatal pulmonary embolism) within 3 months. [ Time Frame: 3 months ]

Secondary Outcome Measures :
  1. Asymptomatic proximal thrombus extension at 2 weeks [ Time Frame: 2 weeks ]
  2. Time course of symptom resolution and the proportion of patients with complete resolution at two weeks. [ Time Frame: 2 weeks ]
    Time course of symptom resolution including time to complete resolution of symptoms, and the proportion of patients with complete resolution at two weeks.

  3. All-cause mortality [ Time Frame: 3 months ]
  4. Post-thrombotic syndrome [ Time Frame: 6 months ]
  5. Predictors of recurrent or progressive DVT or new PE [ Time Frame: 3 months ]

Eligibility Criteria

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Patients aged 18 years or older with acute symptomatic provoked or unprovoked distal vein thrombosis (axial or muscular veins but not involving trifurcation or distal popliteal vein)
  • Absence of symptomatic pulmonary embolism

Exclusion Criteria:

  • DVT involving trifurcation or more proximal leg veins on imaging
  • Prior DVT
  • Active malignancy ie present at time of diagnosis, or on treatment, or treatment completed within 3 months
  • Ongoing risk factors for propagation e.g. immobility (>50% of day in bed or ≥72 hours), plaster cast or non-weight bearing
  • Other indication for therapeutic anticoagulation (e.g. AF)
  • Active gastro-oesophageal ulceration or bleeding
  • Other high risk for bleeding (e.g. recent neurosurgery, vascular retinopathy, coagulopathy)
  • Platelet count <80 x 109/L
  • Renal impairment (CrCl <30ml/min) • Pregnancy or lactation
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01252420

Australia, New South Wales
Prince of Wales Hospital Not yet recruiting
Sydney, New South Wales, Australia, 2031
Contact: Tim Brighton, MBBs, MD    +61293829013    Tim.Brighton@SESIAHS.HEALTH.NSW.GOV.AU   
Principal Investigator: Tim Brighton, MBBs, MD         
Australia, South Australia
Royal Adelaide Hospital Not yet recruiting
Adelaide, South Australia, Australia, 5000
Contact: Simon McRae, MBBs, BMedSci    +61 448882279      
Principal Investigator: Simon McRae, MBBs, BMedSci         
Australia, Victoria
Monash Medical Centre, Southern Health Recruiting
Melbourne, Victoria, Australia, 3168
Contact: Eileen Merriman, MBChB    +61 450011998    eileen.merriman@southernhealth.org.au   
Contact: Huyen Tran, MBBS, BClinEpi    +61 408780785    huyen.tran@southernhealth.org.au   
Principal Investigator: Huyen Tran, MBBs, MClinEp         
Sub-Investigator: Eileen Merriman, MBChB         
Sub-Investigator: Sanjeev Chunilal, MBChB         
New Zealand
Christchurch Hospital Not yet recruiting
Christchurch, Canterbury, New Zealand, 8011
Contact: Mark Smith, MBChB    +64 3 3640640    mark.smith@cdhb.govt.nz   
Principal Investigator: Mark Smith, MBChB         
Sponsors and Collaborators
Monash Medical Centre
Southern Health, Victoria
Eastern Health, Victoria
Royal Adelaide Hospital, Adelaide
Prince of Wales Hospital, Sydney
Christchurch Hospital, NZ
Auckland City Hospital
North Shore Hospital, New Zealand
Middlemore Hospital, New Zealand
Principal Investigator: Huyen Tran, MBBs(Hons), MClin Epidem Monash Medical Centre
More Information

Responsible Party: Huyen Tran, Monash Medical Centre, Southern Health
ClinicalTrials.gov Identifier: NCT01252420     History of Changes
Other Study ID Numbers: DDVTANZ
First Posted: December 3, 2010    Key Record Dates
Last Update Posted: December 6, 2010
Last Verified: July 2010

Keywords provided by Monash Medical Centre:
Distal Vein Thrombosis
Proximal Vein Thrombosis
Pulmonary Embolism
Post-thrombotic syndrome
Limited duration treatment

Additional relevant MeSH terms:
Pulmonary Embolism
Venous Thrombosis
Embolism and Thrombosis
Vascular Diseases
Cardiovascular Diseases
Lung Diseases
Respiratory Tract Diseases
Heparin, Low-Molecular-Weight
Fibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action