Heparin-induced thrombocytopenia: comparison between response to fondaparinux and lepirudin

Background Patients with heparin-induced thrombocytopenia (HIT) require anticoagulation with alternative immediate acting anticoagulants such as lepirudin. Lepirudin may generate antibodies that increase risk of bleeding. Fondaparinux, on the other hand, is structurally too short to induce antibody formation, and therefore, it could be a useful agent for the treatment of HIT. Setting University teaching hospital in Saudi Arabia. Method A retrospective study was conducted at a university teaching hospital on HIT cases which were diagnosed between January 2006 and December 2009. The diagnosis was based on clinical findings consistent with HIT presentation (i.e., a confirmed fall in the platelet count to < 100 x 10(9)/L or a 50% reduction from baseline, four or more days after starting heparin therapy, with exclusion of other causes of thrombocytopenia) and a positive immunoassay test. Results Twelve HIT patients (6 males and 6 females) met the inclusion criteria. Fondaparinux was given to five subjects while lepirudin was utilized in seven patients. The median age was 65 years in the fondaparinux group, and 55 years in the lepirudin group. Nine patients (75%) were on heparin infusion, while three (25%) were on subcutaneous heparin or heparin flushes prior to HIT diagnosis. Frequencies of concomitant chronic diseases as well as other treatments including antiplatelets were similar between the two groups (P > 0.05). The time for platelets recovery was similar between the two groups (Median = 4 days for both arms; P = 0.736). Furthermore, fondaparinux therapy was associated with bigger area under platelet count compared to lepirudin (8,179 vs. 5,768 cell x 10(9)*day/L; P = 0.0303), and higher nadir counts (89 vs. 44 cell x 10(9)/L; P = 0.061). Conclusion The current study suggests that fondaparinux is a potential alternative treatment for HIT. Further larger studies are needed to confirm our findings.