The identification and management of heparin-induced thrombocytopenia in the vascular patient.

Heparin-induced thrombocytopenia (HIT) is a serious, acquired, prothrombotic disorder caused by an antibody response to the heparin-platelet factor 4 complex, which can precipitate arterial as well as venous thromboembolic complications. HIT should be suspected in patients exposed to heparin who present with an unexplained thrombosis or a significant drop in platelet count, or both. Once HIT is suspected or identified, there are specific approaches to its diagnosis and management, with emphasis on removal of all heparin compounds and administration of alternative nonheparin anticoagulants. Generally, HIT is a self-limiting syndrome that resolves when the antibody titers disappear. Patients should be anticoagulated for up to 6 months, depending on the clinical scenario; however, the management of patients with remote or recent HIT requiring a vascular procedure requires special considerations.