What should be given preoperatively to a patient undergoing surgery who has no active bleeding but a prolonged prothrombin time (elevated INR)?

Management of Prolonged PT/INR in Preoperative Patients Without Active Bleeding

For a patient scheduled for surgery with prolonged PT (elevated INR) but no active bleeding, do not routinely administer fresh frozen plasma, prothrombin complex concentrate, or high-dose vitamin K—instead, allow the INR to normalize naturally by withholding warfarin, or use low-dose oral vitamin K (1-2.5 mg) only if the INR remains >1.5 within 1-2 days of surgery. 1

Preoperative INR Thresholds and Timing

• Stop warfarin 5 days before surgery to allow the INR to normalize to <1.5 at the time of the procedure, as recommended by the American College of Chest Physicians. 1

• The target INR for major surgical procedures is <1.5 to minimize bleeding risk while allowing safe surgery. 1

• A prospective study found that stopping warfarin 5 days beforehand resulted in only 7% of patients having an INR >1.5 on the day of surgery. 1

• Check INR on the day before or day of surgery, particularly for patients requiring spinal/epidural anesthesia. 1

When to Use Vitamin K (and When NOT to)

• If INR remains >1.5 one to two days before surgery, consider postponing the procedure rather than routinely administering vitamin K. 1

• The American College of Chest Physicians specifically recommends against routine pre-operative vitamin K for patients with elevated INR (>1.5) 1-2 days before elective surgery/procedure, due to uncertainty about the dose and potential for resistance to post-operative re-anticoagulation. 2

• For high bleeding risk procedures, consider administering 1-2.5 mg oral vitamin K to lower INR to ≤1.5, which typically normalizes INR within 24 hours. 3

• Avoid high-dose vitamin K (>5 mg) as this creates difficulty achieving therapeutic INR postoperatively and may induce a hypercoagulable state. 1

Fresh Frozen Plasma: When It Is (Rarely) Appropriate

• Fresh frozen plasma is reasonable only for patients with mechanical valves who require interruption of warfarin therapy for emergency noncardiac surgery, invasive procedures, or dental care. 4

• FFP is preferable to high-dose vitamin K in this specific emergency scenario. 4

• FFP should NOT be used for routine preoperative INR correction in non-emergency settings, as it does not meaningfully improve hemostatic capacity and carries risks of fluid overload and transfusion reactions. 4

• In patients with cirrhosis, no studies have demonstrated the efficacy of prophylactic FFP in preventing bleeding in patients undergoing invasive procedures. 4

Prothrombin Complex Concentrate: Reserved for Emergencies Only

• PCC is NOT indicated for asymptomatic patients with prolonged INR scheduled for elective surgery. 2

• PCC is reserved for life-threatening or critical-site bleeding (intracranial, intraspinal, intraocular, pericardial, retroperitoneal) or for emergency surgery where an INR <1.5 is required immediately. 2

• For emergency surgery with elevated INR, administer 4-factor PCC 25-50 U/kg IV plus vitamin K 5-10 mg by slow IV infusion over 30 minutes, targeting INR <1.5. 2, 5

Special Populations Requiring Bridging Anticoagulation

• High-risk patients include those with mechanical mitral valve or any mechanical valve with additional risk factors (atrial fibrillation, prior thromboembolism, LV dysfunction). 1

• In patients at high risk of thrombosis, therapeutic doses of intravenous unfractionated heparin should be started when the INR falls below 2.0 (typically 48 hours before surgery), stopped 4-6 hours before the procedure, restarted as early after surgery as bleeding stability allows, and continued until the INR is again therapeutic with warfarin therapy. 4

• In patients at low risk of thrombosis (bileaflet mechanical AVR with no risk factors), warfarin can be stopped 48-72 hours before the procedure (so the INR falls to less than 1.5) and restarted within 24 hours after the procedure—heparin is usually unnecessary. 4

Postoperative Management

• Resume warfarin 12-24 hours after surgery when adequate hemostasis is achieved, using the patient's usual maintenance dose rather than double-dosing. 1

• For patients who required bridging, continue therapeutic anticoagulation until INR has been in therapeutic range for at least 48 hours. 3

Common Pitfalls to Avoid

• Do not administer vitamin K intravenously when not necessary, as this can lead to anaphylactic reactions (3 per 100,000 doses). 2, 3

• Avoid unnecessary correction of minimally elevated INR values (e.g., INR 1.3-1.5), as this may increase thrombotic risk without improving surgical safety. 1, 3

• In patients with mechanical heart valves, extreme caution should be exercised with vitamin K administration to avoid valve thrombosis, and never allow INR to fall rapidly. 1

• Baseline INR is associated with the rate of normalization after stopping warfarin, but it has limited utility as a predictor in clinical practice—whenever normal hemostasis is considered crucial for safety, the INR should be checked again before the invasive procedure. 6

Algorithm for Decision-Making

1. Five days before surgery: Stop warfarin in all patients except those undergoing low-risk procedures who can proceed with therapeutic INR. 1

2. One to two days before surgery: Check INR. 1

   • If INR <1.5: Proceed with surgery. 1
   • If INR 1.5-2.0 and high bleeding risk procedure: Consider 1-2.5 mg oral vitamin K. 3
   • If INR >2.0: Consider postponing surgery or administering 1-2.5 mg oral vitamin K. 1, 3

3. Day of surgery: Recheck INR, especially for neuraxial anesthesia. 1

4. Emergency surgery with elevated INR: Administer 4-factor PCC plus vitamin K 5-10 mg IV. 2, 5