HEPARIN-INDUCED THROMBOCYTOPAENIA/THROMBOSIS: A CLINICOPATHOLOGIC REVIEW

Background: Heparin is widely used for the prophylaxis of venous thrombo-embolismand pulmonary embolism. Thrombocytopaenia and the sequale of thrombosis areuncommon adverse effects of therapy which are associated with high morbidity andmortality.Objective: To review the clinical-pathologic features of heparin inducedthrombocytopaenia/thrombosis.Data sources: Reputable haematology journals and the internet in English. Searchesincluded thrombosis, heparin, and heparin induced thrombocytopaenia.Data selection: Only relevant journals and internet sources were selected for thisreview. In particular leading journals in thrombosis and anticoagulants.Data extraction: High quality abstracts, papers and internet articles were the mainsource of information.Data synthesis: Information from the selected abstracts and papers was used for thepaper.Conclusion: 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 relatedthe formation of heparin-platelet factor 4 antibodies which can be demonstrated inthe laboratory by functional and immunoassays. Management requires alternativeanticoagulation with agents that have no cross reactivity with heparin platelet factor 4antibodies. These agents include danapranoid, direct thrombin inhibitors and neweragents like fondaparinux and rivaroxaban with anti Xa activity