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Anticoagulant TherapyPhase 4NCT07515664

Vitamin K for Perioperative Warfarin Management

A Phase 4 study testing Vitamin K, Warfarin (standard without loading) and Warfarin (standard with loading) in people with Anticoagulant Therapy, run by University of Michigan at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

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

Who is it for?
Ages 18 years and older
Conditions the study is for
Anticoagulant Therapy
What is being tested?
Vitamin K, Warfarin (standard without loading) and Warfarin (standard with loading)
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
20 participants
Where
1 siteUnited States
Study dates
3 Jul 2025to Aug 2026
Phase
Phase 4
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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

Who cannot join

  • 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)
Show all 9Show fewer
  • 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)

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Geoffrey Barnes, MD contact

734 936-4000

gbarnes@med.umich.edu

United States1 site, 1 recruiting

  • Michigan Medicine

    Ann Arbor, Michigan, 48109

    Geoffrey Barnes, MD, 734 936-4000, gbarnes@med.umich.edu

    Recruiting

Other trials in United States

About this study

Official title: 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.

Read the 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.

Being tested
Vitamin K, Warfarin (standard without loading), Warfarin (standard with loading)

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Vitamin KDrug

    10 mg of oral vitamin K will be given approximately 36-48 hours before procedure.

  • Warfarin (standard without loading)Drug

    Also called Coumadin

    Patients receive their standard warfarin dosing without interruption.

  • Warfarin (standard with loading)Drug

    Also called Coumadin

    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.

Study groups in NCT07515664
Study groupRoleWhat they receive
Standard Warfarin Dosing with Vitamin KExperimentalPatients 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.
Receives: Drug: Vitamin K; Drug: Warfarin (standard without loading)
Loading Warfarin Dosing with Vitamin KExperimentalPatients 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.
Receives: Drug: Vitamin K; Drug: Warfarin (standard with loading)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Feasibility of patient recruitment

    Percentage of recruited patients among those initially screened

    Measured: Within two weeks (from outreach to five days prior to procedure)

  2. INR reversal

    Percentage of enrolled patients with an INR less than or equal to 1.5 on morning of procedure

    Measured: Within 12 hours prior to procedure

Secondary outcomes (9)

  1. Fidelity to intervention protocol

    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

    Measured: 12 day span from 2 days pre-operative through 10 days post-operative

  2. Fidelity to randomization

    Percent of patients who used the appropriate dose of warfarin that was recommended immediately post -procedure based on randomization

    Measured: 24 hours (day of procedure)

  3. Cost per recruited patient

    Study costs per patient recruited through end of follow up. Inclusive of personnel, supplied, medication costs.

    Measured: 12 day span from 2 days pre-operative through 10 days post-operative

  4. Patient acceptability

    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.

    Measured: 10 days post procedure

  5. Clinical acceptability

    Data gathered with an acceptability survey, on a Likert scale ranging from 1-5 where 5 means most acceptable and 1 means least acceptable.

    Measured: 10 days post procedure

  6. Therapeutic INR by post-operative day 5

    Percent of patients whose INR has returned to their therapeutic range by day 5 post-procedure

    Measured: day 5 post procedure

  7. Adverse events

    Any bleeding or thromboembolic complication that occurs with 30-days following the surgical procedure

    Measured: 30 days post procedure

  8. Canceled procedures

    Percent of procedures that are canceled due to an INR greater than 1.5

    Measured: 24 hours prior to procedure

  9. Additional warfarin reversal pre-operative

    Use of any additional warfarin reversal agents (e.g., fresh frozen plasma, prothrombin complex concentrate, additional vitamin K)

    Measured: 24 hours pre-procedure

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted7 Apr 2026
  2. Study start3 Jul 2025
  3. Primary completionAug 2026 (estimated)
  4. Study completionAug 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 4
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
20 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07515664
Sponsor's protocol ID
HUM00264031
Other IDs
K24HL179410
Status last verified
Apr 2026
First submitted
31 Mar 2026
Last updated
13 Apr 2026
Results posted
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Vitamin K, Warfarin (standard without loading) and Warfarin (standard with loading) in people with Anticoagulant Therapy, run by University of Michigan at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 13 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Geoffrey Barnes, MD (734 936-4000, gbarnes@med.umich.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Feasibility of patient recruitment (time frame: Within two weeks (from outreach to five days prior to procedure)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07515664.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Apr 2026.

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