Related Experiment Video
Updated: Dec 6, 2025

Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
Emergent reversal of oral factor Xa inhibitors with four-factor prothrombin complex concentrate
Louis Lipari1, Sam Yang2, Brian Milligan3
1Department of Pharmacy, Research Medical Center, Kansas City, MO, USA.
Background:
Controversy exists regarding first-line use of the recently approved reversal agent andexanet alfa due to limitations of the ANEXXA-4 study, thrombotic risks, and high medication acquisition cost. The purpose of this study was to evaluate the safety and effectiveness of 4F-PCC for the reversal of emergent oral fXa inhibitor-related bleeding. Furthermore, we aimed to evaluate a subgroup using strict ANNEXA-4 patient selection criteria.
Methods:
This was a retrospective study conducted utilizing chart review of adult patients that received 4F-PCC for oral fXa inhibitor-related bleeding. The primary endpoint was the rate of clinical success defined as achieving excellent or good hemostatic effectiveness following the administration of 4F-PCC. Secondary endpoints included in-hospital mortality and arterial/venous thromboembolism, and cost compared with andexanet alfa.
Results:
A total of 119 patients were included, with 83 patients in the ANNEXA-4 criteria subgroup. Eighty-five of the 119 patients (71%) required reversal due to intracranial bleeding. Prior to reversal, 70 patients (59%) were taking apixaban and 49 patients (41%) were taking rivaroxaban. Clinical success was achieved in 106 of 119 patients (89%) and 74 of 83 patients (90%) in the strict criteria subgroup. Three of 119 patients (2.5%) had a thrombotic event during hospital stay and the overall mortality rate was 13%. The average cost increase of andexanet alfa compared to 4F-PCC would have been $29,500 per patient.
Conclusions:
Administration of 4F-PCC for the reversal of oral fXa inhibitors was effective with relatively low thrombotic risk. Further direct prospective comparison of 4F-PCC to andexanet alfa is warranted.
Related Concept Videos
Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants
Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...
Venous Thrombosis III: Interprofessional Care
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
Coagulation
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...
Clot Retraction and Fibrinolysis

