Efficacy and Safety of Fondaparinux in Patients With Suspected Heparin-Induced Thrombocytopenia

Objective: Heparin-induced thrombocytopenia (HIT) occurs in up to 5% of patients exposed to unfractionated heparin for 5 or more days. Direct thrombin inhibitors (DTIs) are currently the only Food and Drug Administration (FDA)-approved agents for the treatment of HIT. The purpose of this study is to determine whether fondaparinux is an appropriate first-line alternative anticoagulant in patients with suspected or confirmed HIT. Methods: A retrospective study was conducted by identifying all patients who received a DTI or fondaparinux during a 5 year period, August 2009-August 2014. Patients were included if they had a HIT panel/serotonin-release assay analysis (regardless of the result) and were initiated on a DTI or fondaparinux for alternative anticoagulation. The primary outcome was new, recurrent, or progressive thromboembolic event. Secondary outcomes included bleeding events, platelet count recovery, and hospital stay. Results: A total of 1022 patients were evaluated, and 47 patients met the inclusion criteria. Twelve patients were HIT positive and 35 were HIT negative. Seven (14.9%) of the 47 patients experienced a new thrombosis, none of whom were on fondaparinux only (FONDA). There were 4 new minor bleeds, with 1 bleed as a result of being on fondaparinux. FONDA treatment resulted in a slightly shorter median duration of hospital stay compared to the DTI-only group and the DTI followed by fondaparinux group. There is a potential for cost savings with fondaparinux due to the ease of administration and availability to be given in the outpatient setting. Conclusion: In this small retrospective review, fondaparinux appeared similarly efficacious and safe compared to DTIs for the treatment of suspected HIT.