Vitamin K for Perioperative Warfarin Management

April 6, 2026 updated by: Geoffrey Barnes, University of Michigan

Vitamin K Reversal of INR for Perioperative Management of Warfarin: : A Pilot Study to Assess Feasibility

This is a feasibility study of uninterrupted warfarin with a one time dose of Vitamin K before a surgical procedure.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Historically, warfarin is held for 5 days before a surgical procedure to obtain a safe INR (international normalized ratio) that minimizes bleeding risk. However, there is a strong rationale for continuing warfarin uninterrupted in the perioperative space and giving a one-time vitamin K dose to get a safe INR pre-operatively. This feasibility study will recruit patients who use warfarin and will measure their INR response after receiving a single pre-procedure vitamin K dose. This study will also assess the use of a one-time "loading" dose immediately post-operative to help the INR return to the therapeutic range sooner than continuing with the standard warfarin dosing.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Michigan
      • Ann Arbor, Michigan, United States, 48109
        • Recruiting
        • Michigan Medicine
        • Contact:

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Warfarin therapy for ≥3 months
  • Use of home INR testing equipment
  • Scheduled for a surgical procedure that requires INR ≤ 1.5 (typically achieved with warfarin interruption)
  • INR ≤ 4 on day 7-10 prior to procedure

Exclusion Criteria:

  • Surgical procedure does not require INR ≤1.5 (typically achieved with warfarin interruption)
  • Surgical procedure with a high risk of bleeding or complications (urologic procedures, bronchoscopy, epidural injections, nerve blocks, spinal surgery)
  • Warfarin therapy for < 3 months
  • Lack of English language proficiency
  • Use of a Heartmate II or HVAD left ventricular assist device
  • Recent thrombotic event (within 3 months)
  • CHA2DS2-VASc score >6
  • INR >4 on day 7-10 prior to procedure
  • Hypersensitivity to any component of Vitamin K or simple syrup (used in the compounding process)

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 Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Standard Warfarin Dosing with Vitamin K
Patients will receive their standard warfarin dosing before, during, and after their procedure. This is in addition to a one time dose of oral vitamin K pre-procedure.
Drug: Vitamin K
10 mg of oral vitamin K will be given approximately 36-48 hours before procedure.
Drug: Warfarin (standard without loading)
Patients receive their standard warfarin dosing without interruption.
Other Names:
  • Coumadin
Experimental: Loading Warfarin Dosing with Vitamin K
Patients will receive their standard warfarin dosing before and during their procedure. On the night following the procedure, they will receive a one time loading dose of warfarin (twice their normal dose). Patients will then resume normal dosing of warfarin. This is in addition to a one time dose of oral vitamin K pre-procedure.
Drug: Vitamin K
10 mg of oral vitamin K will be given approximately 36-48 hours before procedure.
Drug: Warfarin (standard with loading)
Patients receive their standard warfarin dosing without interruption; patients also receive a one time loading dose (twice normal dose) of warfarin on the evening following their procedure.
Other Names:
  • Coumadin

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Feasibility of patient recruitment
Time Frame: Within two weeks (from outreach to five days prior to procedure)
Percentage of recruited patients among those initially screened
Within two weeks (from outreach to five days prior to procedure)
INR reversal
Time Frame: Within 12 hours prior to procedure
Percentage of enrolled patients with an INR less than or equal to 1.5 on morning of procedure
Within 12 hours prior to procedure

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Fidelity to intervention protocol
Time Frame: 12 day span from 2 days pre-operative through 10 days post-operative
Percent of patients who achieved both elements of the intervention: 1) continued warfarin uninterrupted peri-operatively; 2) Administration of oral vitamin K on the evening of pre-operative day 2
12 day span from 2 days pre-operative through 10 days post-operative
Fidelity to randomization
Time Frame: 24 hours (day of procedure)
Percent of patients who used the appropriate dose of warfarin that was recommended immediately post -procedure based on randomization
24 hours (day of procedure)
Cost per recruited patient
Time Frame: 12 day span from 2 days pre-operative through 10 days post-operative
Study costs per patient recruited through end of follow up. Inclusive of personnel, supplied, medication costs.
12 day span from 2 days pre-operative through 10 days post-operative
Patient acceptability
Time Frame: 10 days post procedure
Data gathered with an acceptability survey, measured on a Likert scale ranging from 1-5 where 5 means most acceptable and 1 means least acceptable.
10 days post procedure
Clinical acceptability
Time Frame: 10 days post procedure
Data gathered with an acceptability survey, on a Likert scale ranging from 1-5 where 5 means most acceptable and 1 means least acceptable.
10 days post procedure
Therapeutic INR by post-operative day 5
Time Frame: day 5 post procedure
Percent of patients whose INR has returned to their therapeutic range by day 5 post-procedure
day 5 post procedure
Adverse events
Time Frame: 30 days post procedure
Any bleeding or thromboembolic complication that occurs with 30-days following the surgical procedure
30 days post procedure
Canceled procedures
Time Frame: 24 hours prior to procedure
Percent of procedures that are canceled due to an INR greater than 1.5
24 hours prior to procedure
Additional warfarin reversal pre-operative
Time Frame: 24 hours pre-procedure
Use of any additional warfarin reversal agents (e.g., fresh frozen plasma, prothrombin complex concentrate, additional vitamin K)
24 hours pre-procedure

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Michigan

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Heart, Lung, and Blood Institute (NHLBI)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Geoffrey Barnes, MD, University of Michigan

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 3, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 31, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 31, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 7, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 6, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HUM00264031
  • K24HL179410 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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