Laboratory monitoring of direct oral anticoagulants (DOACs)—The perfect storm?

The current armamentarium of anticoagulant drugs is broad and multifaceted (1) (Figure 1). Historically, anticoagulant treatment has been based on administration of vitamin K antagonists (VKAs; especially warfarin and syntrom), which mainly act by reducing the synthesis of active vitamin K-dependent factors (factors II, VII, IX and X). Due to a long lag phase of anticoagulation induction, the additional inhibitory effect on two physiological inhibitors of blood coagulation (i.e., protein C and protein S) and the narrow therapeutic range, VKAs have been supported for decades with initial and/or additional use of heparins/derivatives (1).