Thrombopénie induite à  l'héparine et syndrome coronarien aigu

Heparin-induced thrombocytopenia (HIT) is a relatively common immune-mediated disorder due to the development of IgG antibody specific to platelet factor 4. More frequent with the use of unfractionated heparine after the 5th day of treatment, this complication is defined as a decrease in platelet count of up to 40% and/or < 100,000 and is associated with new venous or arterial thromboses in 50% cases. The association between HIT and acute coronary syndrome is rare. Heparin withdrawal and treatment with an alternative antithrombotic agent have to be initiated prior to laboratory confirmation. Thrombotic complications actually occur rapidly before or simultaneously with platelet decline. The alternative antithrombotic danaparoid sodium (a heparinoid) or lepidurine (a recombinant direct thrombin inhibitor) are available for further anticoagulation with patients affected by HIT. Our case report describe clinical signs of cross reactivity between heparin and danaparoid which then need to be switch to another anticoagulation (lepidurin) despite the risk of bleeding in case of renal failure. In the future, HIT could disappear with a wider use of the new antithrombotic agents, such as fondaparinux and ximelatagran.