Use of Recombinant Hirudin in Heparin-Induced Thrombocytopenia and Thrombosis (HITT) and Renal Failure

Abstract

Treatment of critically ill patients who have heparin-induced thrombocytopenia and throm bosis (HITT) and also renal failure is a challenge. Recombinant hirudin (Refludan, Hoechst Marion Roussel) is a direct thrombin inhibitor indicated for anticoagulation in HITT and approved by the United States Food and Drug Administration. Because this drug is renally cleared, a single dose of hirudin may induce prolonged (up to one week) unpredictable antico agulation in patients with renal insufficiency. There are a few case reports of patients with renal failure and suspected heparin-induced thrombocytopenia (HIT) in which patients were anticoagulated with Refludan for catheter thrombosis. There is no literature on the thera peutic use of Refludan to treat HITT in patients with diffuse thrombosis and renal failure. The authors report the case of a 44-year-old female dialysis patient with HITT and extensive life- threatening thrombosis. The patient developed common iliac vein occlusion extending to the right atrium with progressive right internal jugular vein thrombus developing while on heparin. Her platelet count dropped to 60,000/μL. She was lethargic and hemodynamically unstable. Refludan was initially given as a bolus of 0.2 mg/kg (total, 12 mg) at a 50% dose reduction based on the patient's ideal body weight. This dose was based on the published pharmacoki netics of Refludan in patients with renal failure. Only 2 additional boluses of 6 mg and 3 mg were needed to extend the duration of therapeutic anticoagulation (measured by PTT) to 140 hours. The patient improved both clinically and radiographically after the treatment with Refludan. There were no additional thromboembolic events or bleeding complications. The platelets returned to normal within a few days. The patient was transitioned to coumadin and discharged from the hospital. She remains stable at 1-year follow-up.