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NCT Number: NCT07515664

Vitamin K for Perioperative Warfarin Management

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

Recruiting

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Key information

Conditions

Anticoagulant Therapy

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Michigan Medicine

Ann Arbor, Michigan, 48109, United States

Location status: Recruiting

Location contact

Geoffrey Barnes, MD

CONTACT

[email protected]

734 936-4000

About this study

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.

Who can participate

Healthy volunteers accepted: No

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

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)

Treatment and study plan

Vitamin K

Drug

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

Warfarin (standard without loading)

Drug

Patients receive their standard warfarin dosing without interruption.

Other names: Coumadin

Warfarin (standard with loading)

Drug

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

Primary outcomes

  1. 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

  2. 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

Secondary outcomes

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Adverse events

    Time frame: 30 days post procedure

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

  8. Canceled procedures

    Time frame: 24 hours prior to procedure

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

  9. 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)

Study contacts

Contact information is provided by the study sponsor or research team.

Geoffrey Barnes, MD

CONTACT

[email protected]

734 936-4000

Sponsors and collaborators

Lead sponsor

University of Michigan

Other

Collaborators

  • National Heart, Lung, and Blood Institute (NHLBI)

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Apr 7, 2026
Registry last updated
Apr 13, 2026

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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