Evaluation of Treatment with Direct Thrombin Inhibitors in Patients with Heparin-Induced Thrombocytopenia

Abstract

To evaluate the efficacy, safety, and associated costs of anticoagulation with argatroban, bivalirudin, and lepirudin for managing patients with heparin-induced thrombocytopenia (HIT) or presumed HIT. Retrospective medical record review. University-affiliated teaching hospital. Forty-two patients who were hospitalized between January 1 and December 31, 2004, and who were treated with bivalirudin, argatroban, or lepirudin for at least 24 hours. The primary outcome was the time to reach the desired goal for activated partial thromboplastin time (aPTT). Secondary outcomes were the number of aPTT measurements within the therapeutic range, costs, treatment duration, clinical outcomes, and adverse events. Of the 42 patients who met the inclusion criteria, 24 received bivalirudin, 13 received argatroban, and 5 received lepirudin. Patients receiving bivalirudin who reached therapeutic aPTTs attained them sooner than those receiving either argatroban or lepirudin (8.5 vs 14 and 24 hrs, respectively, p=0.124). Average percentage of therapeutic aPTTs/patient was greatest in the argatroban group (62%), followed by the bivalirudin (57%) and lepirudin (29%) groups (p=0.062). Average drug cost/day/patient was greater in the lepirudin group than the other groups, whereas average laboratory costs were similar among groups. Treatment duration was longer with argatroban than with bivalirudin or lepirudin. Bleeding rates were similar in the argatroban and bivalirudin groups, but higher than in the lepirudin group. A composite of clinical outcomes (deep vein thrombosis, nonfatal myocardial infarction, nonfatal stroke, limb amputation, and all-cause mortality) were similar among the three groups. All three drugs were effective as anticoagulants for patients with HIT or presumed HIT. Based on average use and average wholesale price, bivalirudin cost less per day than the other two agents. Although not yet approved by the United States Food and Drug Administration for management of HIT, bivalirudin appears to be a viable treatment alternative for anticoagulation therapy.