[Postoperative heparin-induced thrombopenia with thromboembolism (HITT)--a rare complication of heparin therapy?]

Many surgical patients receive either unfractionated or low-molecular weight heparin in a prophylactic or therapeutic intention. Feared upon the administration of heparin is the heparin-induced thrombopenia (HIT). In HIT type 1, the heparin directly interacts with the platelets. The platelet count rarely falls below 100,000/microliter and normalizes again despite continuous administration of heparin. In HIT type 2 or HIT with thrombosis (HITT) the platelet count usually falls more than 50% and due to an antibody-dependent platelet activation, thromboembolic episodes may occur. Compared to non-surgical patients, the incidence of HITT in the postoperative phase is markedly increased. In suspicion of a HITT, heparins should immediately be stopped and replaced by an alternative coagulant because of a high risk of further thromboembolic complications. Direct thrombin-inhibitors such as the recombinant hirudins are considered to be safe and effective. They have no heparin-like immunological properties and therefore, they seem to become the therapeutic and prophylactic "gold-standard" in patients with HITT.