When should Clexane (enoxaparin) be withheld prior to surgery?

Timing of Clexane (Enoxaparin) Discontinuation Before Surgery

Preoperative Discontinuation Recommendations

For patients receiving therapeutic-dose enoxaparin, the last dose should be administered approximately 24 hours before surgery rather than 10-12 hours before the procedure to reduce bleeding risk. 1

Timing Based on Bleeding Risk

Low to Moderate Bleeding Risk Surgery:

• Discontinue therapeutic-dose enoxaparin at least 24 hours before surgery
• For prophylactic doses:
  • Last dose can be given 12-24 hours before surgery
  • For surgical patients receiving prophylactic doses, enoxaparin should be given 10-12 hours preoperatively 1

High Bleeding Risk Surgery:

• Discontinue therapeutic-dose enoxaparin at least 24 hours before surgery
• Consider longer intervals (up to 48 hours) for patients with impaired renal function
• For patients undergoing neuraxial anesthesia, prophylactic doses of enoxaparin should not be administered within 10-12 hours before the procedure 1

Specific Surgical Scenarios

Cardiac Surgery (CABG):

• For patients undergoing CABG, low molecular weight heparins should be discontinued at least 12-24 hours before surgery 1
• Resumption should be based on adequate surgical site hemostasis

Bariatric Surgery:

• Preoperative prophylactic enoxaparin (40 mg) should be administered 10-12 hours before surgery 1
• Higher doses may be considered for obese patients

Postoperative Resumption Recommendations

• For low to moderate bleeding risk surgery: Resume enoxaparin at least 24 hours after surgery 1
• For high bleeding risk surgery: Wait at least 48-72 hours before resuming therapeutic-dose enoxaparin 1
• When neuraxial anesthesia is used, the first dose of enoxaparin can be administered 6-8 hours postoperatively, and after catheter removal, no earlier than 2 hours afterward 1

Special Considerations

Renal Function

• Enoxaparin is dependent on significant renal clearance
• Avoid in patients with creatinine clearance <30 mL/minute or adjust dose based on anti-factor Xa levels 1

Obesity

• Standard fixed-dose regimens may lead to suboptimal anticoagulation in obese patients
• Consider weight-based dosing (0.5 mg/kg twice daily) for obese patients 2
• For morbidly obese patients, intermediate doses may be more appropriate 1

Bleeding Risk Assessment

• Major bleeding rates with therapeutic-dose LMWH resumed within 24 hours after surgery can be as high as 20% for major surgeries (>1 hour duration) 1
• The risk of bleeding must be balanced against the risk of thrombosis

Common Pitfalls to Avoid

1. Inadequate Discontinuation Time: Failing to stop enoxaparin early enough before surgery can lead to increased perioperative bleeding

2. One-Size-Fits-All Approach: Different surgical procedures have different bleeding risks and may require individualized timing of discontinuation

3. Ignoring Renal Function: Patients with impaired renal function may require longer discontinuation periods due to prolonged drug half-life

4. Resuming Too Early: Resuming therapeutic doses too soon after surgery (especially high bleeding risk procedures) can significantly increase bleeding complications

5. Neuraxial Anesthesia Considerations: Special timing is required when neuraxial anesthesia is planned to prevent spinal/epidural hematoma

In conclusion, the timing of Clexane discontinuation should be based on the bleeding risk of the procedure, the dose being administered (prophylactic vs. therapeutic), and patient-specific factors such as renal function. The strongest evidence supports discontinuing therapeutic-dose enoxaparin 24 hours before surgery and waiting at least 24 hours after surgery before resuming, with longer intervals for high bleeding risk procedures.