The Effect of Vasopressors on the Anti Xa Response to Enoxaparin in Critically Ill Patients

April 19, 2016 updated by: Dr Sharon Einav, Shaare Zedek Medical Center

Prospective Randomised Study of the Effect of Vasopressors on the Anti Xa Response to Enoxaparin in Critically Ill Patients

The purpose of this study is to evaluate the efficacy of 3 different dosing regimens of enoxaparin in achieving adequate antithrombotic aFXa levels in critically ill patients.

The relationship between appearance of DVT and antithrombotic aFXa levels will also be assessed and risk factors associated with inadequate aFXa levels under standard enoxaparin dosages will be searched for.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Critically ill patients are at increased risk of venous thrombosis and embolism from DVT. Low molecular weigh heparins such as enoxaparin (clexane) have more favorable pharmacokinetic/ pharmacodynamic profiles, equivalent or improved efficacy (e.g. in post trauma and orthopedic surgery patients) and fewer bleeding complications than low-dose unfractionated heparin. These medications are currently recommended for DVT prophylaxis in critically ill patients and are usually administered subcutaneously (SQ). The antithrombotic activity of LMWHs correlates with peak aFXa levels. However, the the appropriate dose and dosing interval of enoxaparin for DVT prophylaxis in critically ill surgical patients has not been established and in particular remains unknown for those patients with severe peripheral edema ans/or decreased peripheral circulation due to therapy with vasopressors. Several studies have recently demonstrated questionable efficacy of standard daily enoxaparin dosing for critically ill patients as DVT prophylaxis.

The current study will be a prospective, randomized, cohort study, conducted at the Shaare Zedek Medical Center over a period of 1 year (100 patients). All critically ill patients aged ≥18 years with a predicted requirement of mechanical ventilation for >3 days will be included. Data collection will be performed anonymously and will include patient demographics and admission details, duplex monitoring for DVT and daily recording of APACHE II scores, renal function, coagulation profile and overall dose of vasopressors.

Patients will be randomized to receive enoxaparin in accordance three DVT prophylaxis protocols- IV by weight, SQ by weight or SQ 40mg x1/day (standard). Blood samples for the evaluation of aFXa will be drawn twice daily for peak and trough activity over a period of 5 days. No further changes will be made in the standard therapy. Patient outcomes and occurrence of adverse events will be recorded. The principle outcome variable will be achievement of target peak and trough levels of aFXa during the 5 day study period.

Study Type

Interventional

Enrollment (Actual)

39

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Jerusalem, Israel, 91031
        • Shaare Zedek Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

All critically ill patients, aged ≥18 years, with a predicted requirement for mechanical ventilation of more than 3 days and for whom venous thromboembolic prophylaxis is indicated.

-

Exclusion Criteria:

  1. Patients requiring full anticoagulation
  2. Administration of unfractionated heparin in the 8hrs preceding study entry
  3. Existing contraindication to prophylactic dose of enoxaparin.
  4. Platelets < 75,000
  5. Significant renal failure (creatinine clearance <30 ml/min/m2) [39]
  6. BMI > 30
  7. INR > 1.7
  8. Any conditions precluding treatment in the opinion of the primary physician
  9. Patient /surrogate refusal

    -

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: IV by weight
intravenous dose of 0.5 mg/kg enoxaparin once daily

Patients considered eligible will be divided into 2 groups- those receiving vasopressor support and those not receiving vasopressor support at the time of inclusion. The patients in each group will be randomized to receive enoxaparin in accordance with one of the following DVT prophylaxis protocols:

  1. Intravenous Enoxaparine according to their weight (0.5mg/kg x 1/day)
  2. Subcutaneous Enoxaparine according to their weight (0.5mg/kg x 1/day)
  3. Subcutaneous Enoxaparine 40mg x1/day
Active Comparator: SC fixed dose
subcutaneous fixed dose of 40 mg enoxaparin once daily

Patients considered eligible will be divided into 2 groups- those receiving vasopressor support and those not receiving vasopressor support at the time of inclusion. The patients in each group will be randomized to receive enoxaparin in accordance with one of the following DVT prophylaxis protocols:

  1. Intravenous Enoxaparine according to their weight (0.5mg/kg x 1/day)
  2. Subcutaneous Enoxaparine according to their weight (0.5mg/kg x 1/day)
  3. Subcutaneous Enoxaparine 40mg x1/day
Active Comparator: SC by weight
subcutaneous dose of 0.5 mg/kg enoxaparin once daily

Patients considered eligible will be divided into 2 groups- those receiving vasopressor support and those not receiving vasopressor support at the time of inclusion. The patients in each group will be randomized to receive enoxaparin in accordance with one of the following DVT prophylaxis protocols:

  1. Intravenous Enoxaparine according to their weight (0.5mg/kg x 1/day)
  2. Subcutaneous Enoxaparine according to their weight (0.5mg/kg x 1/day)
  3. Subcutaneous Enoxaparine 40mg x1/day

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
To determine the effect of the dosing protocols of enoxaparin for critically ill patients on aFXa activity
Time Frame: 5 days
5 days

Secondary Outcome Measures

Outcome Measure
Time Frame
bleeding/thrombotic complications
Time Frame: 7 days
7 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: Sharon Einav-Bromiker, MD, Shaare Zedek Medical Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 2007

Primary Completion (Actual)

April 1, 2014

Study Completion (Actual)

September 1, 2015

Study Registration Dates

First Submitted

July 12, 2006

First Submitted That Met QC Criteria

July 12, 2006

First Posted (Estimate)

July 13, 2006

Study Record Updates

Last Update Posted (Estimate)

April 20, 2016

Last Update Submitted That Met QC Criteria

April 19, 2016

Last Verified

April 1, 2016

More Information

Terms related to this study

Other Study ID Numbers

  • einav-1-ctil

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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