Warfarin:

• INR Monitoring: Assess the patient's INR before surgery. For most procedures, an INR of 2.0-3.0 is generally acceptable for lower bleeding risk surgeries. For higher bleeding risk surgeries, an INR closer to 1.5 may be targeted.
• Discontinuation: Warfarin is typically stopped 5 days before surgery to allow for a decrease in the INR. If the INR is not at the desired level, vitamin K or fresh frozen plasma can be considered to rapidly reverse the anticoagulant effect.
• Bridging Therapy: For high thrombotic risk patients with mechanical heart valves or prior thromboembolism, bridging with LMWH may be considered during the interruption of warfarin.

‍Direct Oral Anticoagulants (DOACs):

• Renal Function Assessment: Consider renal function when deciding on the timing of DOAC discontinuation and reinitiation. Drugs like dabigatran, rivaroxaban, apixaban, and edoxaban have different half-lives influenced by renal function.
• Timing of Discontinuation: For low bleeding risk surgeries, DOACs are generally stopped 24-72 hours before the procedure. For high bleeding risk surgeries, discontinuation is typically longer.
• Reinitiation Post-surgery: Reinitiate DOACs postoperatively based on the patient's bleeding risk and the need for thromboprophylaxis. Ensure hemostasis is achieved before restarting anticoagulation.

‍Antiplatelet Agents (Aspirin, Clopidogrel):

• Timing of Discontinuation: Aspirin is typically stopped 7-10 days before elective surgery. Clopidogrel cessation depends on the specific surgical bleeding risk, and its discontinuation timing can vary from 5 to 7 days before surgery.

‍Bridge Therapy:

• High-Risk Patients: Patients at high thrombotic risk (e.g., those with mechanical heart valves) might need bridging therapy with LMWH or unfractionated heparin during the perioperative period when anticoagulants are temporarily stopped.

‍Postoperative Resumption:

• Restarting Anticoagulation: The decision to restart anticoagulation post-surgery depends on achieving hemostasis, the patient's bleeding risk, and the risk of thrombosis. Generally, anticoagulation is resumed as soon as it is safe post-surgery.

‍Special Considerations:

• Regional Anesthesia: Assess the risk of spinal/epidural hematomas for patients on anticoagulants, especially when planning regional anesthesia.

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Bridge Therapy

Indications:

‍Bridge therapy is considered for high-risk patients with mechanical heart valves, atrial fibrillation with high thromboembolic risk, recent thromboembolism, or other conditions requiring continuous anticoagulation.

‍Agents Used for Bridging:

• Low Molecular Weight Heparin (LMWH): Enoxaparin, dalteparin, or fondaparinux are commonly used.
• Unfractionated Heparin (UFH): Given intravenously or subcutaneously.

‍Timing of Bridge Therapy:

• Stopping Oral Anticoagulants: Warfarin is stopped several days before surgery. DOACs are usually stopped 24-72 hours before the procedure.
• Starting Bridge Therapy: Typically initiated when the oral anticoagulant is discontinued and continued until the perioperative period is over or until the patient can resume oral anticoagulants.

‍Bridge Therapy Dosage:

• LMWH: Dosage is based on weight and renal function. For instance, enoxaparin might be dosed at 1 mg/kg every 12 hours or 1.5 mg/kg once daily.
• UFH: Adjusted based on activated partial thromboplastin time (aPTT) monitoring.

‍Bridging and Postoperative Resumption:

• Warfarin: Typically restarted 12-24 hours post-surgery if hemostasis is achieved and the risk of bleeding is acceptable.
• DOACs: Often resumed within 24-48 hours post-surgery if hemostasis is achieved and the patient's bleeding risk allows.

‍Bridge Therapy Continuation:

• Bridge therapy is usually continued until the oral anticoagulant reaches therapeutic levels.

‍Special Considerations for Bridging:

• Renal Function: Adjustments in LMWH dosing are necessary in patients with renal impairment.
• Monitoring and Dose Adjustment: Monitoring of anticoagulant activity might be needed during bridge therapy, especially for UFH, to prevent excessive anticoagulation.

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