Does the patient need to be anticoagulated before surgery?

Perioperative Anticoagulation Management

The patient should receive bridging anticoagulation before surgery if they are at moderate to high risk for cardiovascular events, with the last dose of therapeutic LMWH administered approximately 24 hours before surgery. 1

Assessment of Thromboembolism Risk

The decision to provide bridging anticoagulation depends primarily on the patient's risk of thromboembolism:

• High risk patients (requiring bridging):

  • Mechanical heart valve
  • Recent venous thromboembolism (<3 months)
  • Atrial fibrillation with CHA₂DS₂-VASc score ≥4
  • Recent stroke/TIA (<3 months)
  • Recent coronary stent placement (BMS <6 weeks, DES <6 months) 1, 2

• Moderate risk patients (consider bridging):

  • Atrial fibrillation with CHA₂DS₂-VASc score of 2-3
  • Older mechanical heart valve
  • Venous thromboembolism within past 3-12 months 1

• Low risk patients (no bridging needed):

  • Atrial fibrillation with CHA₂DS₂-VASc score 0-1
  • Venous thromboembolism >12 months ago
  • No prior thromboembolism 1

Bridging Protocol

If bridging is indicated based on thromboembolism risk assessment:

1. Discontinue warfarin 5-6 days before surgery to allow INR to normalize to ≤1.5 2

2. Start therapeutic-dose LMWH when INR falls below therapeutic range (typically 3 days before surgery) 2

3. Administer last preoperative LMWH dose approximately 24 hours before surgery rather than 12 hours before surgery 1, 2

   • For once-daily regimen: Give half the total dose the morning before surgery
   • For twice-daily regimen: Skip the evening dose before surgery 1

4. Check INR on the morning of surgery to ensure it's ≤1.5 2

Postoperative Anticoagulation Management

The timing of postoperative anticoagulation depends on the bleeding risk of the procedure:

1. Resume warfarin on the evening of surgery or the next morning at the usual maintenance dose 2

2. For high bleeding risk procedures:

   • Resume therapeutic-dose LMWH 48-72 hours after surgery 1
   • Ensure adequate surgical site hemostasis before restarting 1, 2

3. For non-high bleeding risk procedures:

   • Resume therapeutic-dose LMWH approximately 24 hours after surgery 1

4. Continue LMWH until INR returns to therapeutic range (typically 4-5 days) 2

Special Considerations

• For patients with mechanical heart valves or recent thromboembolism: Bridging is strongly recommended due to high thrombotic risk 1

• For patients with drug-eluting stents placed within 6 months: Consider continuing dual antiplatelet therapy through surgery if possible, or at minimum continuing aspirin 1

• For patients receiving IV unfractionated heparin: Stop the infusion 4-6 hours before surgery 1

• For minor procedures (dental, dermatologic, cataract surgery): Consider continuing warfarin throughout the procedure rather than interrupting 1, 3

Monitoring

• Monitor for signs of bleeding (surgical site bleeding, hematoma formation)
• Monitor for signs of thromboembolism (neurological changes, shortness of breath)
• Check INR regularly during the perioperative period, especially before restarting LMWH 2

The decision to provide bridging anticoagulation requires balancing the risks of perioperative thromboembolism against bleeding complications. For most patients at moderate to high thrombotic risk, bridging with therapeutic-dose LMWH is appropriate, with careful attention to the timing of the last preoperative dose and the resumption of postoperative anticoagulation.