Lepirudin is a safe and effective anticoagulant for patients with heparin-associated antiplatelet antibodies

Objective: The purpose of this study was to determine whether lepirudin, a direct thrombin inhibitor, is a safe and effective anticoagulant for patien ts with heparin-associated antiplatelet antibodies (HAAbs). Methods: The charts of HAAb-positive patients who received lepirudin were r eviewed. Lepirudin use was analyzed for indication, duration, and effective ness of anticoagulation, and for adverse events. HAAb presence was determin ed by platelet aggregation. Results: Eighteen HAAb-positive patients received lepirudin: 9 had previous documentation of HAAb, 6 had thrombocytopenia while receiving heparin; and 3 had HAAb after a thrombotic event. The indications for lepirudin anticoa gulation included thromboembolism prophylaxis (5), arterial thromboses (5), pulmonary embolus (3) or deep venous thrombosis (1), and one each for atri al fibrillation, myocardial infarction, artificial heart valves, and hemodi alysis access. The average duration of therapy was 4.04 days. Fifteen patie nts achieved adequate anticoagulation (activated partial thromboplastin tim e [aPTT] ratio > 2.0) with lepirudin. Seven patients had aPTTs that were so metimes supratherapeutic (aPTT > 100 seconds) but did not bleed. In all pat ients who had heparin-induced thrombocytopenia, platelet counts were normal ized while they received lepirudin. There were two complications: one patie nt fell, and had a calf hematoma (aPTT ratio 3.24), and one patient who rec eived lepirudin during nine separate hospitalizations had epistaxis (aPTT r atio 2.86) during her ninth hospitalization. Another patient received lepir udin during two hospitalizations without an adverse event. Conclusion: Lepirudin is a safe and effective anticoagulant for patients wi th HAAbs. The platelet counts of all patients with heparin-induced thromboc ytopenia were normalized while they received lepirudin. Careful monitoring of the aPTT and avoidance of trauma while patients are receiving lepirudin are recommended.