Heparin-induced thrombocytopenia and thrombosis syndrome: in vivo cross-reactivity with danaparoid and successful treatment with r-Hirudin.

Heparin-induced thrombocytopenia and thrombosis syndrome (HITTS) is an immune-mediated drug reaction that occurs 5-14 d after initiation of heparin therapy and is a potentially life-threatening thrombotic complication. The antibody-heparin-PF4 complexes cause platelet activation and generation of platelet microparticles. The need for anticoagulant treatment in asymptomatic thrombocytopenia is uncertain. However, treatment is warranted in HITTS, as illustrated in the case reported here. Danaparoid, r-Hirudin and argatroban are effective drugs. Danaparoid has a 10-50% in vitro cross-reactivity rate with the HIT antibodies, but has been proven to be clinically efficacious even in these cases. Here, we report a case of in vivo cross-reactivity with danaparoid, the patient showed an excellent recovery with r-Hirudin.