Uninterrupted warfarin with a single vitamin K dose for surgery
Official title: Vitamin K Reversal of INR for Perioperative Management of Warfarin: : A Pilot Study to Assess Feasibility
Run by University of Michigan · NCT07515664 · Data updated 2026-11-12
This study tries giving one dose of vitamin K before surgery to people on long-term warfarin to see if they can safely keep taking warfarin through the procedure.
Quick facts
| Phase | Phase 4 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 20 (estimated) |
| Sponsor | University of Michigan Academic / other |
| Locations | 1 site (Ann Arbor, Michigan) |
| Status | Recruiting |
| Started | July 3, 2025 |
| Main results expected | August 2026 |
| Study ends | August 2026 |
| Registry record updated | April 13, 2026 |
| Trial ID | NCT07515664 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are adults on stable warfarin therapy for at least three months who use home INR testing, have an INR ≤ 4 at screening (day 7–10 before procedure), and are scheduled for a procedure requiring an INR ≤ 1.5.
✕Probably not a fit
Patients undergoing high-bleeding-risk procedures, those with recent thrombotic events, very high stroke risk (CHA2DS2-VASc > 6), LVADs, lack of English proficiency, or INR > 4 at screening are excluded and unlikely to benefit from this approach.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This feasibility study tests continuing warfarin without interruption and giving a single preoperative oral vitamin K dose to lower INR to a safe level before surgery. Participants must have been on warfarin for at least three months, use home INR testing, and be scheduled for a procedure that typically requires an INR ≤ 1.5. Investigators will measure INR responses after the single pre-procedure vitamin K dose and will also compare whether an immediate postoperative vitamin K loading dose helps the INR return to therapeutic range faster than standard warfarin resumption. The study is being conducted at Michigan Medicine and uses home INR monitoring to track perioperative INR changes.
Why it matters
Potential benefit: If successful, this approach could allow patients to avoid stopping warfarin around surgery and return to therapeutic INR sooner, potentially lowering clot risk from missed doses.
How similar studies have gone: There is limited prior data on uninterrupted warfarin with a single pre-op vitamin K dose, so this specific strategy remains largely untested in controlled trials.
Who can join: the full rules
Show full inclusion / exclusion criteria
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)
Where it's running
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Michigan Medicine
Ann Arbor, Michigan, United States Recruiting
Study contacts
- Principal investigator: Geoffrey Barnes, MD — University of Michigan
- Study coordinator: Geoffrey Barnes, MD
- Email: gbarnes@med.umich.edu
- Phone: 734 936-4000
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.