Abstract
Many patients with venous thromboembolism (VTE) are at risk of recurrence if anticoagulant
therapy is stopped. Whereas 3 months of anticoagulation treatment is sufficient for
patients with VTE provoked by major surgery or trauma, in many cases a longer course
is needed. Extended therapy with vitamin K antagonists (VKAs) requires frequent coagulation
monitoring and dose adjustments to ensure that the international normalized ratio
(INR) remains within the therapeutic range; furthermore, there is a risk of major
bleeding even if a therapeutic INR is maintained. Therefore, more convenient and safer
anticoagulants are needed.
The non-VKA oral anticoagulants (NOACs)—apixaban, dabigatran, edoxaban and rivaroxaban—simplify
extended therapy because they can be given in fixed doses without routine coagulation
monitoring. Randomized clinical trials have demonstrated the efficacy and safety of
NOACs for extended VTE treatment, but bleeding remains a concern. Patients and physicians
may, therefore, be reluctant to continue anticoagulation beyond 3 to 6 months except
in patients at high risk of recurrence. Acetylsalicylic acid (ASA) is often prescribed
instead of an anticoagulant because of its perceived lower risk of bleeding; however,
the recent EINSTEIN CHOICE trial demonstrated that once-daily rivaroxaban at a dose
of either 20 or 10 mg reduced the risk of recurrent VTE by 70% compared with ASA without
significantly increasing the risk of bleeding. In this review, we discuss the EINSTEIN
CHOICE trial in the context of previous trials for extended VTE treatment and examine
some of the lessons that can be applied to clinical practice.
Keywords
venous thromboembolism - anticoagulation - extended therapy - rivaroxaban - acetylsalicylic
acid
