Should therapeutic Clexane (enoxaparin) 100mg twice daily be withheld the day prior to return to theatre in a man with a mechanical aortic valve and previously on Warfarin (coumarin)?

From the Guidelines

Therapeutic enoxaparin (Clexane) should be withheld 24 hours before returning to theater for a patient with a mechanical aortic valve, with the last dose given approximately 24 hours before surgery. For this patient on enoxaparin 100mg twice daily, this means holding the evening dose the day before and the morning dose on the day of surgery. This timing allows the anticoagulant effect to diminish sufficiently to reduce bleeding risk during surgery, as supported by the most recent guidelines and studies, including the 2022 American College of Chest Physicians clinical practice guideline on perioperative management of antithrombotic therapy 1. Some key points to consider in the management of anticoagulation in patients with mechanical heart valves include:

• The risk of thromboembolism versus the risk of surgical bleeding must be balanced, with mechanical aortic valves being thrombogenic but brief interruption of anticoagulation generally considered acceptable for necessary procedures when managed appropriately.
• For patients with mechanical heart valves who are at high risk of thrombosis, consider bridging with intravenous unfractionated heparin, which can be stopped 4-6 hours before surgery and provides more precise control, as discussed in the context of perioperative antithrombotic management 1.
• After surgery, enoxaparin can typically be restarted 24-48 hours postoperatively when hemostasis is secure, based on clinical judgment and the specific patient's risk factors. The decision to withhold anticoagulation should be made on a case-by-case basis, taking into account the patient's individual risk factors for thromboembolism and bleeding, and guided by the most recent and highest quality evidence available, such as the 2022 guideline from the American College of Chest Physicians 1.

From the Research

Anticoagulation Management for Mechanical Aortic Valve

• The management of anticoagulation in patients with mechanical aortic valves is crucial to prevent thromboembolic events and valve thrombosis 2, 3.
• For patients on therapeutic clexane (enoxaparin), the decision to withhold it before returning to theatre depends on various factors, including the patient's individual risk of thromboembolism and bleeding 4, 5.

Risk of Thromboembolism and Bleeding

• Patients with mechanical aortic valves are at high risk of thromboembolism, and anticoagulation therapy is essential to prevent this complication 2, 3.
• However, anticoagulation therapy also increases the risk of bleeding, particularly in patients with a history of bleeding events or those who are taking other medications that increase the risk of bleeding 4, 5.

Bridging Anticoagulation Therapy

• Bridging anticoagulation therapy with intravenous unfractionated heparin or subcutaneous low-molecular weight heparin may increase the risk of bleeding in patients undergoing mechanical aortic valve replacement 5.
• The use of bridging anticoagulation therapy should be carefully considered on a case-by-case basis, taking into account the patient's individual risk factors and medical history 5.

Management of Anticoagulation in the Perioperative Period

• The management of anticoagulation in the perioperative period for patients with mechanical aortic valves requires careful planning and monitoring to minimize the risk of thromboembolism and bleeding 2, 4, 3, 5.
• The decision to withhold or continue anticoagulation therapy before surgery should be made in consultation with a multidisciplinary team, including cardiologists, surgeons, and anesthesiologists 4.