Background: Heparin-induced thrombocytopenia (HIT) syndrome is an immune-mediated disorder producing thrombocytopenia and thrombosis, with or without prior exposure to heparin. Although avoidance of heparin products and non-heparin anticoagulants are used, immune-based therapies including intravenous immunoglobulin have been tried when the thrombocytopenia persists or there is breakthrough thrombosis. We sought to systematically review and analyze the published literature on use of IVIg in the treatment of HIT.
Methods: A systematic search of PubMed, google scholar, EMBASE, SCOPUS for all study designs and reports were carried out from inception until April 2019. Statistical analysis was done using Microsoft EXCEL and Stata version 13.
Results: In 34 patients with HIT, the mean age was 60 years. About 70% cases were by unfractionated heparin exposure and 30% by low molecular weight heparin (LMWH). The most common precipitant in the patients without heparin exposure was recent surgery. Average nadir platelet count for which IVIg was used was 28,000/microliter. Time from resolution of the thrombocytopenia after IVIg treatment was 3 days with average platelet count recovery to 159,000/microliter. Mean time from diagnosis to administration of IVIg was day 18. Thrombosis was identified in 32% of patients. Dose of IVIg were 0.08 mg/kg to 1mg/kg. Average number of administered doses was 3. About 77% patients improved (platelet count>100,000/microL or cessation of thrombosis) following use of IVIg. Logistic regression did not identify any factors that predicted IVIg response (including baseline platelet count, dose of IVIg used or the presence of thrombosis) (p>0.05). No thrombotic events or other adverse events were noted with use of IVIg.
Conclusions: IVIg appears to be a safe and effective treatment option for HIT-related thrombocytopenia and for refractory thrombosis.