Use of recombinant hirudin in patients with heparin-induced thrombocytopenia with thrombosis requiring cardiopulmonary bypass.

Abstract

HEPARIN-induced thrombocytopenia (HIT) and heparin-induced thrombocytopenia with thrombosis (HITT) are rare but potentially fatal complications of heparin therapy. 1,2 Administration of heparin in patients with HITT causes platelet aggregation, thromboembolism, and thrombocytopenia. Therefore, an alternative anticoagulant to heparin is recommended in these patients. Recombinant hirudin (r-hirudin; Refludan, Hoechst Marion Roussel, Inc., Kansas City, MO) is a direct thrombin inhibitor that has been used in patients with HIT and HITT, and case reports have described its use as an anticoagulant in patients requiring cardiac surgery The ecarin clotting time (ECT) is probably the best marker for anticoagulation with r-hirudin, 6 but this test is not widely available. Furthermore, little information is available on appropriate dosing for patients with renal insufficiency, obesity, or those requiring prolonged cardiopulmonary bypass (CPB). We describe the use of r-hirudin as an anticoagulant in two patients requiring CPB, the first with normal renal function and the second with renal insufficiency. The different dose regimens and the use of activated partial thromboplastin time (aPTT) for monitoring anticoagulation are discussed.