Oral anticoagulation treatment-control, risks, benefits, and informed consent

The most common indications for warfarin therapy are atrial fibrillation, the presence of a mechanical heart valve and venous thromboembolism. The risks and benefits of treatment for these conditions have been fairly well characterized and recent consensus groups have provided guidelines which are nearly identical. Although we can define the recommended range of the PT in INR units, it is often difficult under the best of circumstances to keep the INR in the desired range. Physicians often dont recognize the limitations of INR testing. Furthermore, the continued risk of thromboembolic and bleeding complications despite state of the art treatment might not be recognized by the patient. This places the physician at risk of a malpractice suit and emphasizes the need for informed consent. The following review will summarize current recommendations for the major conditions requiring long-term management with oral anticoagulants, identify problems with PT-INR testing, consider when the laboratory should contact the physician urgently, define acceptable control of the PT-INR during audits, and finally suggest information for the patient, which might be used in an informed consent form.