Recurrent thrombosis rescued by fondaparinux in high‐risk patients: A case series

Background: Recurrent thrombosis treatment options are limited when anticoagulation with dose escalation of low molecular weight heparin or unfractionated heparin fail. Fondaparinux is a pure, synthetic pentasaccharide that consists of heparin's essential five-sugar chain that binds antithrombin to inactivate factor Xa. There is scarce data regarding fondaparinux's use in recurrent thrombosis. Key Clinical Question: We aim to explore fondaparinux's role in recurrent thrombosis when other standard anticoagulation treatments fail. Clinical Approach: We report a case series of six high thrombotic risk patients successfully treated with fondaparinux after thrombosis progression while on supratherapeutic low molecular weight heparin or unfractionated heparin. Of our six patients, two were previously diagnosed with a high-risk thrombophilia: triple positive antiphospholipid syndrome, and homozygous factor V Leiden. The other four had an underlying malignancy. Conclusion: With fondaparinux, no thrombosis progression was observed, and no bleeding complications occurred.