Abstract
Traditionally, venous thromboembolism (VTE) resulting from major transient risk factors
(e.g., surgery or trauma) or a major persistent risk factor such as cancer, has been
defined as being provoked, whereas unprovoked VTE encompasses events without an identifiable
cause. These categorizations influence anticoagulant treatment duration; unlike VTE
provoked by major transient risk factors, extended anticoagulation beyond 3 months
is advised for patients with cancer or unprovoked VTE due to risk persistence after
treatment cessation. However, some patients with VTE provoked by minor transient or
minor persistent risk factors may also be candidates for extended anticoagulation
therapy due to the continuing risk of recurrence. In patients who require extended
therapy, vitamin K antagonists (VKAs) are effective but are associated with an increased
risk of bleeding and various treatment burdens (e.g., anticoagulation monitoring and
dose adjustment). Evaluations of extended VTE treatment with the less-burdensome direct
oral anticoagulants such as apixaban, dabigatran, edoxaban, and rivaroxaban show that
they are at least as safe and effective as VKAs in a broad range of patients. In addition,
apixaban and rivaroxaban offer more than one dosing option, allowing tailoring of
treatment to the patient's specific risk factor profile. Analysis of more granular
definitions for risk factor groupings has also yielded vital information on the most
appropriate strategies for the treatment of patients with specific risk factors, highlighting
that extended anticoagulation treatment may benefit those with minor transient and
persistent environmental and nonenvironmental risk factors who commonly receive shorter-duration
therapy.
Keywords anticoagulants - body weight - frail elderly - renal insufficiency - venous thromboembolism
