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Enoxaparin in Children With Asymptomatic Venous Thrombosis After Pediatric Cardiac Surgery

This study has been withdrawn prior to enrollment.
(Poor enrollment)
Sponsor:
Information provided by (Responsible Party):
Brian McCrindle, The Hospital for Sick Children
ClinicalTrials.gov Identifier:
NCT01474902
First received: November 15, 2011
Last updated: August 25, 2013
Last verified: August 2013
  Purpose

The CATCH-enoxaparin trial is the natural continuation of the CATCH study. It will capitalize on the fact that patients enrolled in the CATCH study will be specifically screened for asymptomatic thromboembolism (TEs) in order to answer important clinical questions.

The investigators propose a randomized controlled trial to address whether, among pediatric patients with congenital heart defects (CHD) recovering from cardiovascular surgery and diagnosed with an asymptomatic venous TE, the use of enoxaparin results in a net therapeutic benefit?


Condition Intervention Phase
Asymptotic Venous Thrombosis
Drug: Enoxaparin
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: A Randomized Controlled Trial of Enoxaparin in Children With Asymptomatic Venous Thrombosis After Pediatric Cardiac Surgery

Resource links provided by NLM:


Further study details as provided by The Hospital for Sick Children:

Primary Outcome Measures:
  • Net therapeutic benefit of enoxaparin [ Time Frame: Events recording from baseline to 18 months post-surgery ] [ Designated as safety issue: No ]
    Defined as the between group difference in proportion of patients with negative outcomes (percent clot conversion to symptomatic + percent major bleeding complications)


Secondary Outcome Measures:
  • Rate of objective clot size progression (or regression) [ Time Frame: Up to 18 months post-surgery ] [ Designated as safety issue: No ]
    This will be determined by serial imaging with ultrasound and frequency of complete clot resolution at the end of the treatment

  • Frequency and Risk Factors for conversion from asymptomatic to symptomatic thromboembolism [ Time Frame: Up to 18months post-surgery ] [ Designated as safety issue: No ]
    Defined as the appearance of any of the following symptoms: swelling, edema, discoloration or high temperature of the affected territory

  • Frequency of and risk factors for post-thrombotic syndrome [ Time Frame: 18 months after surgery ] [ Designated as safety issue: No ]
    Clinical manifestations include varicose veins, edema, skin hyperpigmentation and skin ulcers

  • Frequency of and risk factors for bleeding complications [ Time Frame: Up to 18months ] [ Designated as safety issue: Yes ]
    Minor complications and major episodes defined as cerebral, abdominal, retroperitoneal or pulmonary hemorrhage or any bleeding complications requiring blood transfusions

  • Neurodevelopment and health re-lated quality of life [ Time Frame: 18 months post-surgery ] [ Designated as safety issue: No ]
    Age appropriate PedsQL® generic module and parent report and Child Health Questionnaire


Enrollment: 0
Study Start Date: August 2011
Estimated Study Completion Date: August 2015
Estimated Primary Completion Date: August 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Treatment group

The initial enoxaparin dose will be: 1.75 mg/kg/dose SC q12h for patients ≤ 2 months old or

1 mg/kg/dose SC q12h for patients > 2 months old

Adjust the dose of enoxaparin according to the following monogram. Depending on the Enoxaparin Anti-factor Xa level achieved, successive actions are indicated, including whether to hold the next scheduled dose, whether any dose change is indicated and when the next anti-factor Xa level should be drawn.

Drug: Enoxaparin
Lovenox- Enoxaparin; Sanofi-Aventis Canada Inc.
No Intervention: No-treatment

Detailed Description:

Primary Aim: To address whether, among pediatric patients with congenital heart defects (CHD) recovering from cardiovascular surgery and diagnosed with an asymptomatic venous TE, the use of enoxaparin results in a net therapeutic benefit. We hypothesize that enoxaparin dosed as per age-appropriate algorithms is associated with an increased rate of clot resolution and decreased rate of clot progression/long-term complications in children with CHD and asymptomatic venous TE. Benefits from clot resolution will outweigh the risks associated with the use of enoxaparin resulting in a net therapeutic benefit in favour of enoxaparin use in this context.

Secondary aims of this study are to:

  1. To compare the rate of conversion from asymptomatic to symptomatic TE and/or thromboembolic events between treated and untreated patients. Hypothesis: the use of enoxaparin will significantly reduce the rate of conversion from asymptomatic to symptomatic TE.
  2. To compare the rate of objective clot progression (or regression) by serial imaging with ultrasound and echocardiography between treated and untreated patients. Hypothesis: the use of enoxaparin will significantly increase the rate of clot regression.
  3. To identify factors associated with: TE conversion from asymptomatic to symptomatic, clot resolution and post-thrombotic syndrome in both treated and untreated patients separately. Hypothesis: older children with a more mature coagulation system and those with TEs in superficial vessels (rather than deep/systemic vessels) will have a lower frequency of TE complications.
  4. To establish the rate of bleeding complications (both minor and major) for patients on enoxaparin. Hypothesis: we expect major bleeding complications to be present in 2-3% of treated patients and minor bleeding complications to be frequent.
  Eligibility

Ages Eligible for Study:   up to 18 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  1. Pediatric patients with a cardiac defect (acquired or congenital)
  2. Recent cardiac surgery (during current hospital admission)3) Presence of a venous clot confirmed by appropriate diagnostic imaging methods associated with either ≥ 25% blood vessel occlusion (clot diameter/vessel diameter) OR is ≥ 3mm in absolute diameter
  3. Enrollment in the Heart Centre Biobank Registry
  4. Enrollment in the CATCH main study

Exclusion Criteria:

  1. Clots associated with any of the following symptoms: swelling, edema, discoloration or high temperature of the affected territory.
  2. Clots in a vascular segment/location (arterial clots, intracardiac clots) or with a degree of vessel occlusion which obligatory warrants treatment
  3. Prosthetic heart valve
  4. Active or previous cancer history
  5. Known congenital coagulopathy or thrombophilic disorder
  6. Liver failure (AST, ALT or % bilirubin 2x normal)
  7. Need for anticoagulation for treatment or prophylaxis for other reasons (e.g. BT shunt, recent thrombosis requiring anticoagulation)
  8. Previous documented residual clot within the same vascular territory affected by current asymptomatic clot
  9. Increased bleeding risk reflected by severe thrombocytopenia (platelet count <30,000/ml) and/or coagulopathy (INR >4.0 or aPTT >120s)
  10. Active bleeding or major bleeding <10 days ago (not surgery related)
  11. Previous neurosurgery <14 days ago
  12. Uncontrolled severe hypertension (>95th percentile for age)
  13. Previous proven diagnosis of heparin-induced-thrombocytopenia (HIT) <100 days ago
  14. Absolute contraindication to heparin/LMWH (e.g. severe heparin allergy)
  15. Pregnancy or breastfeeding
  16. No planned follow-up at The Hospital for Sick Children

While most patients will be identified as part of the CATCH study during the pre-discharge full-body vascular ultrasound, some patients who are not enrolled in CATCH will also be identified if an asymptomatic clot is identified during a clinically indicated radiological study. For those patients who are not already enrolled in the CATCH study and the Heart Centre Biobank Registry, they will be approached and consent will be obtained for those studies prior to enrolment in the CATCH-enoxaparin study.

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01474902

Locations
Canada, Ontario
The Hospital for Sick Children
Toronto, Ontario, Canada, M5V1X8
Sponsors and Collaborators
The Hospital for Sick Children
Investigators
Principal Investigator: Brian W McCrindle, MD The Hospital for Sick Children
  More Information

No publications provided

Responsible Party: Brian McCrindle, Staff Cardiologist, The Hospital for Sick Children
ClinicalTrials.gov Identifier: NCT01474902     History of Changes
Other Study ID Numbers: 1000022022
Study First Received: November 15, 2011
Last Updated: August 25, 2013
Health Authority: Canada: Health Canada

Keywords provided by The Hospital for Sick Children:
pediatric
asymptotic venous thrombosis
Enoxaparin
pediatric cardiac surgery

Additional relevant MeSH terms:
Thrombosis
Venous Thromboembolism
Venous Thrombosis
Cardiovascular Diseases
Embolism and Thrombosis
Thromboembolism
Vascular Diseases

ClinicalTrials.gov processed this record on November 23, 2014