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Enoxaparin in Children With Asymptomatic Venous Thrombosis After Pediatric Cardiac Surgery

Primary Purpose

Asymptotic Venous Thrombosis

Status
Withdrawn
Phase
Phase 3
Locations
Canada
Study Type
Interventional
Intervention
Enoxaparin
Sponsored by
The Hospital for Sick Children
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Asymptotic Venous Thrombosis focused on measuring pediatric, asymptotic venous thrombosis, Enoxaparin, pediatric cardiac surgery

Eligibility Criteria

undefined - 18 Years (Child, Adult)All SexesDoes not accept healthy volunteers

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.

Sites / Locations

  • The Hospital for Sick Children

Arms of the Study

Arm 1

Arm 2

Arm Type

Experimental

No Intervention

Arm Label

Treatment group

No-treatment

Arm Description

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.

Outcomes

Primary Outcome Measures

Net therapeutic benefit of enoxaparin
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)
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
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
Clinical manifestations include varicose veins, edema, skin hyperpigmentation and skin ulcers
Frequency of and risk factors for bleeding complications
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
Age appropriate PedsQL® generic module and parent report and Child Health Questionnaire

Full Information

First Posted
November 15, 2011
Last Updated
August 25, 2013
Sponsor
The Hospital for Sick Children
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1. Study Identification

Unique Protocol Identification Number
NCT01474902
Brief Title
Enoxaparin in Children With Asymptomatic Venous Thrombosis After Pediatric Cardiac Surgery
Official Title
A Randomized Controlled Trial of Enoxaparin in Children With Asymptomatic Venous Thrombosis After Pediatric Cardiac Surgery
Study Type
Interventional

2. Study Status

Record Verification Date
August 2013
Overall Recruitment Status
Withdrawn
Why Stopped
Poor enrollment
Study Start Date
August 2011 (undefined)
Primary Completion Date
August 2015 (Anticipated)
Study Completion Date
August 2015 (Anticipated)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
The Hospital for Sick Children

4. Oversight

Data Monitoring Committee
Yes

5. Study Description

Brief Summary
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?
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: 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. 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. 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. 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.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Asymptotic Venous Thrombosis
Keywords
pediatric, asymptotic venous thrombosis, Enoxaparin, pediatric cardiac surgery

7. Study Design

Primary Purpose
Treatment
Study Phase
Phase 3
Interventional Study Model
Parallel Assignment
Masking
None (Open Label)
Allocation
Randomized
Enrollment
0 (Actual)

8. Arms, Groups, and Interventions

Arm Title
Treatment group
Arm Type
Experimental
Arm Description
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.
Arm Title
No-treatment
Arm Type
No Intervention
Intervention Type
Drug
Intervention Name(s)
Enoxaparin
Intervention Description
Lovenox- Enoxaparin; Sanofi-Aventis Canada Inc.
Primary Outcome Measure Information:
Title
Net therapeutic benefit of enoxaparin
Description
Defined as the between group difference in proportion of patients with negative outcomes (percent clot conversion to symptomatic + percent major bleeding complications)
Time Frame
Events recording from baseline to 18 months post-surgery
Secondary Outcome Measure Information:
Title
Rate of objective clot size progression (or regression)
Description
This will be determined by serial imaging with ultrasound and frequency of complete clot resolution at the end of the treatment
Time Frame
Up to 18 months post-surgery
Title
Frequency and Risk Factors for conversion from asymptomatic to symptomatic thromboembolism
Description
Defined as the appearance of any of the following symptoms: swelling, edema, discoloration or high temperature of the affected territory
Time Frame
Up to 18months post-surgery
Title
Frequency of and risk factors for post-thrombotic syndrome
Description
Clinical manifestations include varicose veins, edema, skin hyperpigmentation and skin ulcers
Time Frame
18 months after surgery
Title
Frequency of and risk factors for bleeding complications
Description
Minor complications and major episodes defined as cerebral, abdominal, retroperitoneal or pulmonary hemorrhage or any bleeding complications requiring blood transfusions
Time Frame
Up to 18months
Title
Neurodevelopment and health re-lated quality of life
Description
Age appropriate PedsQL® generic module and parent report and Child Health Questionnaire
Time Frame
18 months post-surgery

10. Eligibility

Sex
All
Maximum Age & Unit of Time
18 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: Pediatric patients with a cardiac defect (acquired or congenital) 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 Enrollment in the Heart Centre Biobank Registry Enrollment in the CATCH main study Exclusion Criteria: Clots associated with any of the following symptoms: swelling, edema, discoloration or high temperature of the affected territory. Clots in a vascular segment/location (arterial clots, intracardiac clots) or with a degree of vessel occlusion which obligatory warrants treatment Prosthetic heart valve Active or previous cancer history Known congenital coagulopathy or thrombophilic disorder Liver failure (AST, ALT or % bilirubin 2x normal) Need for anticoagulation for treatment or prophylaxis for other reasons (e.g. BT shunt, recent thrombosis requiring anticoagulation) Previous documented residual clot within the same vascular territory affected by current asymptomatic clot Increased bleeding risk reflected by severe thrombocytopenia (platelet count <30,000/ml) and/or coagulopathy (INR >4.0 or aPTT >120s) Active bleeding or major bleeding <10 days ago (not surgery related) Previous neurosurgery <14 days ago Uncontrolled severe hypertension (>95th percentile for age) Previous proven diagnosis of heparin-induced-thrombocytopenia (HIT) <100 days ago Absolute contraindication to heparin/LMWH (e.g. severe heparin allergy) Pregnancy or breastfeeding 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.
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Brian W McCrindle, MD
Organizational Affiliation
The Hospital for Sick Children
Official's Role
Principal Investigator
Facility Information:
Facility Name
The Hospital for Sick Children
City
Toronto
State/Province
Ontario
ZIP/Postal Code
M5V1X8
Country
Canada

12. IPD Sharing Statement

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Enoxaparin in Children With Asymptomatic Venous Thrombosis After Pediatric Cardiac Surgery

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