Perioperative management of long-term anticoagulation.

When the need for surgery arises, temporary interruption of long-term anticoagulation exposes patients to additional thrombotic risk. There is no consensus as to how perioperative anticoagulation should be managed in this setting. Based on an individual assessment of risk factors for arterial or venous thromboembolism and the risk of postoperative bleeding, this review outlines an approach to the perioperative management of anticoagulation that is designed to optimize patient safety and efficient delivery of health care. The duration of interruption of oral anticoagulation is minimized by withholding four daily doses of warfarin before surgery, and by restarting warfarin the same day that surgery is performed. This will usually achieve satisfactory coagulation status intraoperatively (e.g., International Normalized Ratio of 1.5 or less) with a low risk of postoperative bleeding. Supplemental prophylaxis with therapeutic doses of heparin, usually unfractionated heparin, can be reserved for patients with the highest risk of thromboembolism. In the preoperative period, this applies to patients who have had an episode of arterial or venous thromboembolism in the preceding month. In the postoperative period, this approach is generally reserved for patients with an episode of venous thromboembolism in the preceding 3 months, and patients with an episode of arterial embolism in the preceding month who have a low risk of bleeding. Differences in the approach to management of anticoagulation before and after surgery relate to the fact that surgery is an important risk factor for venous, but not arterial, thromboembolism, and that recent surgery greatly increases the risk of anticoagulant-induced bleeding. Subcutaneous unfractionated or low-molecular-weight heparin, in doses recommended to prevent venous thromboembolism in high-risk surgical patients, should be administered to in-patients who have a lesser risk of thromboembolism until oral anticoagulation is reestablished.