title: Reversal of warfarin anticoagulation for urgent surgical procedures.
abstract: OBJECTIVE
  Patients treated with warfarin for therapeutic anticoagulation present a challenge for the perioperative management of urgent and emergent surgery. Anticoagulation must be reversed prior to most surgical procedures to prevent intraoperative bleeding. The purpose of this module is to review the options for urgent reversal of warfarin anticoagulation and the indications for each reversal agent. Selection of the appropriate agent is important to reduce unnecessary complications of treatment and to achieve optimal reversal of anticoagulation.
  
  
  RESULTS
  When urgent surgery is required for patients taking warfarin, intravenous vitamin K1 should be used for procedures that can be delayed for six to 12 hr. Vitamin K1 results in the activation of existing clotting factors rather than requiring the synthesis of new proteins, which allows for its relatively rapid onset of action. Intravenous vitamin K1 acts more quickly than oral administration, with reversal of anticoagulation occurring within six to 12 hr vs 18-24 hr, respectively. If surgery cannot be delayed, prothrombin complex concentrates (PCCs) should be given, and intravenous vitamin K1 should be infused concurrently to ensure sustained reversal of anticoagulation. The duration of action of both PCCs and plasma is six hours due to the short half-life of factor VII. Prothrombin complex concentrates contain small amounts of heparin and are contraindicated in patients with heparin-induced thrombocytopenia. Plasma should be used only if PCCs are unavailable or are contraindicated.
  
  
  CONCLUSIONS
  Reversal of warfarin anticoagulation can be achieved in a safe and timely manner when the appropriate agent is selected and administered correctly.
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, Queen's University, 76 Stuart St., Kingston, ON, K7L 2V7, Canada.
authors.forename: Rachel
authors.initials: R
authors.lastname: Curtis
authors.forename: Alexandra
authors.initials: A
authors.lastname: Schweitzer
authors.forename: Janet
authors.initials: J
authors.lastname: van Vlymen
mesh_terms: D000925:Anticoagulants / Q000009:adverse effects / Q000494:pharmacology*; D001779:Blood Coagulation Factors / Q000008:administration & dosage; D016063:Blood Loss, Surgical / Q000517:prevention & control; D006470:Hemorrhage / Q000517:prevention & control*; D006801:Humans; D011300:Preoperative Care / Q000379:methods*; D013997:Time Factors; D010837:Vitamin K 1 / Q000008:administration & dosage; D014859:Warfarin / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D000925:Anticoagulants; D001779:Blood Coagulation Factors; C025667:prothrombin complex concentrates; D014859:Warfarin; D010837:Vitamin K 1