NCT01348074

Reinitiation of Anticoagulation After Temporary Withdrawal of Vitamin K Antagonist

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

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 104 (actual)
• Sponsor: McMaster University · Academic / Other
• Sex: All
• Age: —
• Healthy volunteers: Not accepted

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.

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.

Conditions

• Atrial Fibrillation
• Venous Thromboembolism
• Heart Valve Disease
• Surgery

Interventions

Type	Name	Description
DRUG	Double dose	For each individual the dose on Day 1 and Day 2 will be twice the one normally taken

Timeline

• Start date: 2011-04-01
• Primary completion: 2013-12-01
• Completion: 2013-12-01
• First posted: 2011-05-05
• Last updated: 2016-04-05

Locations

1 site across 1 country: Canada