title: Perioperative management of patients receiving vitamin K antagonists.
abstract: OBJECTIVE
  As the number of patients taking vitamin K antagonists (VKA) is growing, the clinician is increasingly faced with having to make decisions regarding anticoagulation therapy before, during and immediately after surgery. In this article we review the indications for VKA and assess their use in the perioperative period based on available pharmacological and clinical data.
  
  
  METHODS
  An on-line computerized search of Medline was conducted limited to English and French language articles. The bibliographies of relevant articles and additional material from other published sources were retrieved and reviewed.
  
  
  RESULTS
  Assessment of patients taking VKA who need surgery must include three factors: 1) the indication for anticoagulation, which determines the thromboembolic risk; 2) the pharmacokinetics of VKA, which determine the moment at which treatment should be discontinued; and 3) the type of surgery, which determines the hemorrhagic risk. Some patients will need to stop VKA treatment and start a substitution or "bridging" anticoagulant therapy, such as unfractionated heparin or low molecular weight heparin, prior to and after surgery. In patients requiring emergency surgery, prothrombin complex concentrate can be used to improve coagulation and is preferable to, although more expensive than fresh frozen plasma.
  
  
  CONCLUSIONS
  For the perioperative setting, further studies are required to determine the optimal substitution ("bridging") regimen and the clinical circumstances that necessitate substitution therapy.
authors.affiliation: Department of Anesthesiology, Hôpital Erasme, 808, Route de Lennik, 1070 Bruxelles, Belgium. brigitte.ickx@ulb.ac.be
authors.forename: Brigitte E
authors.initials: BE
authors.lastname: Ickx
authors.forename: Annick
authors.initials: A
authors.lastname: Steib
mesh_terms: D000925:Anticoagulants / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000075202:Contraindications; D004632:Emergency Medical Services; D006801:Humans; D016343:Monitoring, Intraoperative; D019990:Perioperative Care; D013514:Surgical Procedures, Operative; D014812:Vitamin K / Q000037:antagonists & inhibitors*
chemical_list: D000925:Anticoagulants; D014812:Vitamin K