Fondaparinux effective treatment for SRA-positive HIT
MedWire News: Patients with acute immune heparin-induced thrombocytopenia (HIT), confirmed by serotonin-release assay (SRA), may benefit from anticoagulant treatment with fondaparinux, suggest study findings.
The findings are of importance, say the researchers, as they show that fondaparinux is a feasible alternative to other anticoagulants commonly used to treat HIT. Indeed, a worldwide shortage of danaparoid resulted in 2 years of treatment unavailability in Canada.
"Our study provides further evidence based on well-characterized patients that fondaparinux can be successfully used to treat SRA-positive HIT, including those with thrombotic complications," say Theodore Warkentin (McMaster University, Hamilton, Ontario, Canada) and co-authors.
For the study, the team reviewed thrombotic and major bleeding outcomes in 16 fondaparinux-treated patients with acute HIT (platelet count <150 x109 l-1), based upon clinical features and a positive platelet SRA (≥20% serotonin release at 0.1-0.3 U/ml heparin). Thrombin-antithrombin (TAT) levels were measured where possible.
In total, 14 patients had undergone surgery (n=11 cardiac, n=3 vascular) and two had an acute stroke, with nine patients having experienced one or more thrombotic events at the time of HIT diagnosis. Following treatment initiation none of the 16 patients developed new, progressive, or recurrent thrombosis. Platelet count recovery (to >150x109 l-1) occurred on average 4 days after commencing treatment.
One patient presenting with acute limb ischemia 4 weeks after surgery developed a limb-threatening calf hematoma and another patient required amputation for a gangrenous right upper limb that preceded initiation of fondaparinux.
TAT levels were reduced (albeit nonsignificantly) within 24 hours of commencing treatment with fondaparinux, and all patients (n=13) transitioned to warfarin did so successfully.
"If clinicians do not have access to a sensitive and specific test for HIT, or need to make treatment decisions before results of such testing are available, they can be reassured that fondaparinux has proven efficacy and safety in preventing and treating thrombosis in diverse clinical settings," conclude the authors in the Journal of Thrombosis and Haemostasis.
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By Ingrid Grasmo