Use of Enoxaparin for the chronically anticoagulated patient before and after procedures

Warfarin is used to either treat or prevent thromboembolism; currently >1 million people are taking this anticoagulant.(1) Patients maintained on warfarin may occasionally need to stop their anticoagulation during invasive procedures. All techniques to manage anticoagulation during procedures may be problematic.(2-4) After stopping warfarin, unfractionated heparin, either high-dose subcutaneous or intravenous, may be started once the international normalized ratio (INR) becomes subtherapeutic. Either form of heparin requires monitoring and often several adjustments before becoming therapeutic. Moreover, most physicians prefer intravenous heparin to be given in the inpatient setting, thus increasing costs. Another approach is to lower the dose of warfarin by approximately one third and perform the invasive procedure when the INR is approximately 1.5. The INR can also be lowered by adding a small dose of vitamin K. This method, however, may carry an increased risk for bleeding, even for less vascular procedures. Also, the use of vitamin K may lead to temporary warfarin resistance. A last option is to hold warfarin 4 to 5 days before the procedure and not to use any anticoagulant until the postoperative period. However, this method may carry a risk for thrombotic complications. The use of enoxaparin may avoid these limitations. It can be given subcutaneously and therefore does not require hospitalization perioperatively. Reports show that low molecular weight heparin, such as enoxaparin, is at least as effective and safe as unfractionated heparin in the prevention and treatment of thrombosis.(5,6) This report details our experience to date using enoxaparin for chronically anticoagulated patients.