Warfarin Resumption After Hip Surgery
Yes, warfarin should be resumed within 24 hours (typically the evening of surgery) after hip surgery in most patients, provided adequate hemostasis has been achieved. 1, 2
Timing and Rationale
The American College of Chest Physicians (2022) specifically recommends resuming warfarin within 24 hours over delaying beyond 24 hours after elective surgery, including major orthopedic procedures like hip surgery. 1 This recommendation is based on evidence showing:
- Early resumption (12-24 hours) is associated with lower thrombotic risk: Arterial thromboembolism rates of only 0.1% compared to 2.4% with delayed resumption (>24 hours) 1, 2
- Bleeding rates remain acceptable: Major bleeding occurred in 2.7% with early resumption versus 8.6% with delayed resumption 1
- Warfarin's delayed onset provides a safety margin: It takes 2-3 days for partial anticoagulant effect and 4-8 days for full therapeutic effect, meaning resuming on postoperative day 1 does not immediately increase bleeding risk 1, 2
Dosing Strategy
Resume at the patient's usual maintenance dose, not a doubled dose. 1, 2 While doubling the dose may achieve therapeutic INR slightly faster (50% vs 13% by day 5), the American College of Chest Physicians recommends against this approach due to practical concerns and lack of significant benefit by day 10. 1
Critical Prerequisites Before Resumption
Warfarin resumption may need to be delayed beyond 24 hours if: 1, 2
- Inadequate surgical site hemostasis is present
- Anticipated need for additional surgical intervention exists
- Patient cannot take oral medications
For hip surgery specifically, which is classified as a high bleeding risk procedure, ensure the surgical site shows adequate hemostasis before resuming. 3, 4
Bridging Considerations
For most patients undergoing hip surgery, bridging anticoagulation is NOT required. 2 However, if the patient has very high thromboembolic risk (mechanical heart valves, recent stroke/TIA, CHA₂DS₂-VASc ≥7): 2
- Wait 48-72 hours after hip surgery before starting therapeutic-dose LMWH bridging 3, 4
- Continue LMWH until INR reaches therapeutic range (≥1.9-2.0) on two consecutive measurements 3, 4
Common Pitfalls to Avoid
- Do not unnecessarily delay warfarin resumption beyond 24 hours, as this significantly increases thrombotic risk without reducing bleeding risk 1, 2
- Do not double the warfarin dose when resuming, as this provides minimal benefit and may increase bleeding risk 1, 2
- Do not start therapeutic-dose LMWH within 48 hours after hip surgery if bridging is needed, as this substantially increases bleeding complications 3, 4
- Ensure clear discharge instructions are provided to patients about when and how to resume warfarin to prevent medication errors 2