For patients with a high risk of thromboembolism, we suggest stopping warfarin therapy approximately 4 days before sur-gery, to allow the INR to return to normal, and beginning therapy with full-dose unfractionated heparin or full-dose low-molecular-weight heparin as the INR falls (Grade 2C). In patients undergoing dental procedures, we suggest the use of tranexamic acid mouthwash (Grade 2B) or epsilon amino caproic acid mouthwash without interrupting anticoagulant therapy (Grade 2B) if there is a concern for local bleeding. For most patients who have a lupus inhibitor, we suggest a therapeutic target INR of 2.5 (range, 2.0 to 3.0) [Grade 2B]. In patients with recurrent thromboembolic events with a therapeutic INR or other additional risk factors, we suggest a target INR of 3.0 (range, 2.5 to 3.5) [Grade 2C]. As models of anticoagulation monitoring and management, we recommend that clinicians incorporate patient education, systematic INR testing, tracking, and follow-up, and good communication with patients concerning results and dosing decisions (Grade 1C+). (CHEST 2004; 126:204S-233S)
Abbreviations: ACC = anticoagulation clinic; AMS = anticoagulation management service; INR = international normalized ratio; ISI = international sensitivity index; LMWH = low-molecular-weight heparin; POC = point of care; PSM = patient selfmanagement; PST = patient self-testing; PT = prothrombin time; SC = subcutaneous; subcutaneously; TTR = time in the therapeutic range; UC = usual care; UFH = unfractionated heparin; VKA = vitamin K antagonist; WHO = World Health Organization he coumarins or vitamin K antagonists (VKAs) have been the mainstay of oral anticoagulant therapy for > 50 years. Their effectiveness has been established by well-designed clinical trials for the primary and secondary prevention of venous thromboembolism, for the prevention of systemic embolism in patients with prosthetic heart valves or atrial fibrillation, for the primary prevention of acute myocardial infarction in high-risk men, and for the prevention of stroke, recurrent infarction, or death in patients with acute myocardial infarction. VKAs are challenging to use in clinical practice for the following reasons: (1) they have a narrow therapeutic window; (2) they exhibit considerable variability in dose response among subjects; (3) they are subject to interactions with drugs and diet; (4) they have laboratory control that can be difficult to standardize; and (5) they have problems in dosing as a result of patient nonadherence and miscommunication between the patient and physician. Since warfarin is the most commonly used VKA worldwide, warfarin will be used interchangeably with VKA or coumarin throughout the following discussion.