Reinitiation of Anticoagulation After Temporary Withdrawal of Vitamin K Antagonist (DOSIDO)

April 1, 2016 updated by: Sam Schulman, McMaster University

Phase II Study of Double Versus Single Reinitiation Dose of Warfarin After Interruption for Surgery

It is not known how to best restart warfarin after temporary withdrawal. Participants will be randomized to two groups. Group 1 will restart warfarin at their usual maintenance dose, group 2 will restart warfarin at double their maintenance dose for two days followed by their usual maintenance dose. The main outcome parameter will be the number of patients who are back in therapeutic INR (international normalized ratio) range 4, and 9 days after restarting anticoagulation with warfarin. Thromboembolic and/or bleeding events will be recorded as additional parameters. These data will be collected by a standardized telephone interview at 1 month. In addition, the investigators will evaluate a possible prothrombotic state by measuring the potential of thrombin generation and D-dimers in the subset of patients visiting HHS-General Hospital for their INR tests.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

We will investigate if it is feasible to use double maintenance dose for the first two administrations of vitamin K antagonists when these drugs were temporarily interrupted and thus keep the time of an increased risk of thromboembolism and duration of "bridging" at a minimum. The control group will consist of patients who resume vitamin K antagonists at their usual maintenance dose. The aim of the study is to establish how to best restart anticoagulation with vitamin K antagonists after temporal withdrawal of these drugs. The main outcome parameter will be the proportion of patients who are back to a therapeutic international normalized ratio (INR) ratio at certain days after restarting vitamin K antagonists. Two additional parameters will be evaluated: Firstly, bleeding and thromboembolic complications will be reported and secondly, a possible prothrombotic state, measured as an elevation of D-dimer, at the initiation of anticoagulation will be evaluated.

Study Type

Interventional

Enrollment (Actual)

104

Phase

  • Phase 2

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

  • Canada
    • Ontario
      • Hamilton, Ontario, Canada, L8L 2X2
        • Thrombosis Service, HHS- General Hospital

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

  • ADULT
  • OLDER_ADULT
  • CHILD

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Current treatment with warfarin
  • Need for temporary interruption for invasive procedure or surgery

Exclusion Criteria:

  • Need for post-operative hospitalization more than one day
  • Participation in another clinical trial
  • No consent given

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: TREATMENT
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: NONE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Double dose
Re-initiation with warfarin at twice the usual maintenance dose the first 2 days, then maintenance dose.
Drug: Double dose
For each individual the dose on Day 1 and Day 2 will be twice the one normally taken
Other Names:
  • Loading dose
No Intervention: Usual maintenance dose
Usual maintenance dose from Day 1, i.e. no postoperative loading dose.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of patients with INR back in therapeutic range Day 5 or Day 10
Time Frame: Day 5-10
Proportion of patients with INR 2.0-3.0 on Day 5 or Day 10 (day of invasive procedure defined as Day 1)
Day 5-10

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Thromboembolic events
Time Frame: 30 days
Objectively verified arterial or venous thromboembolic events
30 days
Major bleeding events
Time Frame: 30 days
Defined by the ISTH criteria of 2010
30 days
Minor bleeding events
Time Frame: 30 days
Any bleeding requiring medical attention but not fulfilling the criteria of Major bleeding
30 days
Laboratory parameters of hypercoagulability
Time Frame: 10 days
Quantitative D-dimer and Thrombin Generation performed in a subset at day of procedure, day 5 and 10 to identify abnormal rise.
10 days

Collaborators and Investigators

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

Sponsor

McMaster University

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.

General Publications

Helpful Links

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

April 1, 2011

Primary Completion (Actual)

December 1, 2013

Study Completion (Actual)

December 1, 2013

Study Registration Dates

First Submitted

May 3, 2011

First Submitted That Met QC Criteria

May 4, 2011

First Posted (Estimate)

May 5, 2011

Study Record Updates

Last Update Posted (Estimate)

April 5, 2016

Last Update Submitted That Met QC Criteria

April 1, 2016

Last Verified

April 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HGH20090520

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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