Optimizing transitions from direct factor Xa inhibitors to unfractionated heparin therapy

Hospitalized patients taking direct factor Xa inhibitors (DFXaIs), such as apixaban and rivaroxaban, often need to be transitioned to unfractionated heparin (UFH). This transition is complicated by residual DFXaI activity, which can lead to anticoagulant stacking and possible increased bleeding risk. The guidance on this transition from the manufacturers does not account for interpatient variability in drug clearance and may not be appropriate for all hospitalized patients.

Residual DFXaI anticoagulation at the time of UFH initiation can result in a period of dual anticoagulation or anticoagulant stacking. This issue is identified most often when heparin is monitored using the anti-factor Xa assay as this assay is highly sensitive to the DFXaI. Several retrospective descriptive studies have reported supratherapeutic heparin levels (above 0.7 units/mL), which can last for days depending on the presence of patient-specific factors that reduce DFXaI clearance. The period of anticoagulant stacking has been associated with bleeding events. With the UFH anti-factor Xa assay detecting both anticoagulants, alternative methods are needed for heparin monitoring when transitioning from a DFXaI to UFH. Limited data describe alternative approaches that can be categorized as approaches that ignore residual DFXaI anticoagulation and ones that account for residual DFXaI anticoagulation. Observational data suggest that approaches that measure baseline residual DFXaI anticoagulation allow for a delay in UFH initiation and can reduce bleeding risk. The authors provide recommendations for hospitals or health systems to consider for optimizing management of the transition from DFXaI to UFH therapy.

Each hospital or health system should develop a structured approach for managing DFXaI to UFH transitions. Ideally, the transition should be managed by pharmacists and involve measurement of residual DFXaI anticoagulation to inform the timing of UFH initiation. Prospective studies are needed to better define best practices.