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

Abstract

Objective: The purpose of this study was to determine whether lepirudin, a direct thrombin inhibitor, is a safe and effective anticoagulant for patients with heparin-associated antiplatelet antibodies (HAAbs). Methods: The charts of HAAb-positive patients who received lepirudin were reviewed. Lepirudin use was analyzed for indication, duration, and effectiveness of anticoagulation, and for adverse events. HAAb presence was determined 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 anticoagulation included thromboembolism prophylaxis (5), arterial thromboses (5), pulmonary embolus (3) or deep venous thrombosis (1), and one each for atrial fibrillation, myocardial infarction, artificial heart valves, and hemodialysis access. The average duration of therapy was 4.04 days. Fifteen patients achieved adequate anticoagulation (activated partial thromboplastin time [aPTT] ratio > 2.0) with lepirudin. Seven patients had aPTTs that were sometimes supratherapeutic (aPTT > 100 seconds) but did not bleed. In all patients who had heparin-induced thrombocytopenia, platelet counts were normalized while they received lepirudin. There were two complications: one patient fell and had a calf hematoma (aPTT ratio 3.24), and one patient who received lepirudin during nine separate hospitalizations had epistaxis (aPTT ratio 2.86) during her ninth hospitalization. Another patient received lepirudin during two hospitalizations without an adverse event. Conclusion: Lepirudin is a safe and effective anticoagulant for patients with HAAbs. The platelet counts of all patients with heparin-induced thrombocytopenia were normalized while they received lepirudin. Careful monitoring of the aPTT and avoidance of trauma while patients are receiving lepirudin are recommended. (J Vasc Surg 2001;34:17-20.)