Heparin-induced thrombocytopenia in cardiac surgery

Heparin-induced thrombocytopenia (HIT) is an immune-mediated disease in which IgG antibodies are formed against the complex of heparin and platelet factor 4. The antigen-antibody complexes formed activate platelets and can trigger massive thrombin generation and possibly thromboembolisms. In cases of a positive diagnosis of an acute HIT, based on clinical scores and specific laboratory tests, anticoagulation is switched to the direct thrombin inhibitor argatroban; however, in patients with acute HIT scheduled for urgent cardiac surgery anticoagulation remains a major dilemma as no safe alternative to heparin/protamine has so far been established. Moreover, current guidelines provide conflicting recommendations regarding the first line anticoagulation regimen under these conditions. This article gives an overview of the pathophysiology and diagnostics of HIT. The management options during cardiac surgery interventions are discussed in the light of current international recommendations.