NCT01348074

Brief Summary

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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
104

participants targeted

Target at P25-P50 for phase_2 atrial-fibrillation

Timeline
Completed

Started Apr 2011

Typical duration for phase_2 atrial-fibrillation

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

April 1, 2011

Completed
1 month until next milestone

First Submitted

Initial submission to the registry

May 3, 2011

Completed
2 days until next milestone

First Posted

Study publicly available on registry

May 5, 2011

Completed
2.6 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2013

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2013

Completed
Last Updated

April 5, 2016

Status Verified

April 1, 2016

Enrollment Period

2.7 years

First QC Date

May 3, 2011

Last Update Submit

April 1, 2016

Conditions

Atrial FibrillationVenous ThromboembolismHeart Valve DiseaseSurgery

Keywords

warfarinsurgerymanagementthromboembolismbleeding

Outcome Measures

Primary Outcomes (1)

  • Proportion of patients with INR back in therapeutic range Day 5 or Day 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 Outcomes (4)

  • Thromboembolic events

    30 days

  • Major bleeding events

    30 days

  • Minor bleeding events

    30 days

  • Laboratory parameters of hypercoagulability

    10 days

Study Arms (2)

Double dose

EXPERIMENTAL

Re-initiation with warfarin at twice the usual maintenance dose the first 2 days, then maintenance dose.

Drug: Double dose

Usual maintenance dose

NO INTERVENTION

Usual maintenance dose from Day 1, i.e. no postoperative loading dose.

Interventions

Double doseDRUG

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

Also known as: Loading dose
Double dose

Eligibility Criteria

Sexall
Healthy VolunteersNo
Age GroupsChild (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

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

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Thrombosis Service, HHS- General Hospital

Hamilton, Ontario, L8L 2X2, Canada

Location

Related Publications (2)

  • Schulman S, El Bouazzaoui B, Eikelboom JW, Zondag M. Clinical factors influencing the sensitivity to warfarin when restarted after surgery. J Intern Med. 2008 Apr;263(4):412-9. doi: 10.1111/j.1365-2796.2007.01913.x. Epub 2008 Jan 16.

    PMID: 18205763BACKGROUND

  • Schulman S, Hwang HG, Eikelboom JW, Kearon C, Pai M, Delaney J. Loading dose vs. maintenance dose of warfarin for reinitiation after invasive procedures: a randomized trial. J Thromb Haemost. 2014 Aug;12(8):1254-9. doi: 10.1111/jth.12613. Epub 2014 Jun 25.

    PMID: 24837794RESULT

Related Links

MeSH Terms

Conditions

Atrial FibrillationVenous ThromboembolismHeart Valve DiseasesThromboembolismHemorrhage

Condition Hierarchy (Ancestors)

Arrhythmias, CardiacHeart DiseasesCardiovascular DiseasesPathologic ProcessesPathological Conditions, Signs and SymptomsEmbolism and ThrombosisVascular Diseases

Study Officials

  • Sam Schulman, MD, PhD

    McMaster University

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
phase 2
Allocation
RANDOMIZED
Masking
NONE
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Prof.

Study Record Dates

First Submitted

May 3, 2011

First Posted

May 5, 2011

Study Start

April 1, 2011

Primary Completion

December 1, 2013

Study Completion

December 1, 2013

Last Updated

April 5, 2016

Record last verified: 2016-04

Data Sharing

IPD Sharing
Will not share

Locations

CA(1)