Heparin-induced thrombocytopenia: an update.

Heparin-induced thrombocytopenia (HIT) is an immune response to heparin that can progress to severe thrombosis, amputation, and in some cases death. The diagnosis and treatment of HIT is complex, but needs to be considered in the clinical management of patients exposed to heparin due to its serious outcomes. Early diagnosis based on a comprehensive interpretation of clinical and laboratory information improves clinical outcomes. This begins with careful monitoring for thrombocytopenia and thrombosis during and for at least 5 to 10 days after heparin treatment of any dose and duration. Appropriate use and knowledgeable interpretation of laboratory tests for HIT are important, as these vary in sensitivity and specificity, with each type providing unique information. Clinical management of patients with HIT is with a non-heparin anticoagulant such as a direct thrombin inhibitor or danaparoid followed by a vitamin K antagonist for long-term treatment. Important drug-specific limitations, dosing, and monitoring guidelines must be respected for patient safety. There continues to be new developments in the field of HIT: laboratory testing, clinical scoring systems, and available new anticoagulants. Research and clinical studies will continue to address the unresolved issues and unmet clinical needs associated with HIT. This review summarizes the clinical management of HIT. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.