Heparin-induced thrombocytopaenia/thrombosis: a clinicopathologic review

Heparin is widely used for the prophylaxis of venous thrombo-embolism and pulmonary embolism. Thrombocytopaenia and the sequale of thrombosis are uncommon adverse effects of therapy which are associated with high morbidity and mortality.

To review the clinical-pathologic features of heparin induced thrombocytopaenia/thrombosis.

Reputable haematology journals and the internet in English. Searches included thrombosis, heparin, and heparin induced thrombocytopaenia.

Only relevant journals and internet sources were selected for this review. In particular leading journals in thrombosis and anticoagulants.

High quality abstracts, papers and internet articles were the main source of information.

Information from the selected abstracts and papers was used'for the paper.

The clinical effects of heparin induced thrombocytopaenia/thrombosis (HIT/T) include venous and arterial events the latter of which include limb ischaemia, myocardial infarction and stroke. The pathogenesis of this complication is related the formation of heparin-platelet factor 4 antibodies which can be demonstrated in the laboratory by functional and immunoassays. Management requires alternative anticoagulation with agents that have no cross reactivity with heparin platelet factor 4 antibodies. These agents include danapranoid, direct thrombin inhibitors and newer agents like fondaparinux and rivaroxaban with anti Xa activity.