Perioperative management of the chronically anticoagulated patient.

Common indications for chronic anticoagulation include mechanical prosthetic heart valve, non-rheumatic atrial fibrillation, and venous thromboembolism. Perioperative management of the chronically anticoagulated patient is a complex medical problem, and includes the following issues: urgency of surgery, risk of thromboembolism in the absence of anticoagulation, bleeding risk, consequences of bleeding, ability to control bleeding physically, and duration of bleeding risk after the procedure. Most patients can be managed safely by stopping oral anticoagulants 4-5 days before surgery and restarting anticoagulation after the procedure at the patient's usual daily dose. In general, dental procedures and cataract extraction can be performed without interrupting anticoagulation. Most other procedures can be safely performed with an INR < or = 1.4. For patients with double-wing prosthetic valves (e.g., St. Jude, Carbomedics) in the aortic position, uncomplicated atrial fibrillation, or a remote (>3 months) history of venous thromboembolism, oral anticoagulants can be stopped 4-5 days before surgery and restarted at the usual daily dose immediately after surgery. For other patients at higher risk of thrombosis, "bridging therapy" with outpatient low molecular weight heparin is safe and effective. For urgent procedures, a small dose of oral vitamin K usually will reduce the INR within 24-36 hours to a level sufficient for surgery and avoids exposure to transfused blood products.