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Completed

NCT Number: NCT01348074

Reinitiation of Anticoagulation After Temporary Withdrawal of Vitamin K Antagonist

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.

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Key information

Conditions

Atrial Fibrillation Arrhythmias, Cardiac Cardiovascular Diseases Embolism and Thrombosis Heart Diseases Heart Valve Disease Heart Valve Diseases Hemorrhage Pathologic Processes Pathological Conditions, Signs and Symptoms Surgery Thromboembolism Vascular Diseases Venous Thromboembolism

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Thrombosis Service, HHS- General Hospital

Hamilton, Ontario, L8L 2X2, Canada

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Double dose

Drug

For each individual the dose on Day 1 and Day 2 will be twice the one normally taken

Other names: Loading dose

Primary outcomes

  1. 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)

Secondary outcomes

  1. Thromboembolic events

    Time frame: 30 days

    Objectively verified arterial or venous thromboembolic events

  2. Major bleeding events

    Time frame: 30 days

    Defined by the ISTH criteria of 2010

  3. Minor bleeding events

    Time frame: 30 days

    Any bleeding requiring medical attention but not fulfilling the criteria of Major bleeding

  4. 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.

Sponsors and collaborators

Lead sponsor

McMaster University

Other

Registry information

Official study title

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

Acronym: DOSIDO

Important dates

Study start
2011
Primary completion
2013
Study completion
2013
First posted
May 5, 2011
Registry last updated
Apr 5, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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