Argatroban dosing of patients with heparin-induced thrombocytopenia and an elevated aPTT due to antiphospholipid antibody syndrome

OBJECTIVE: To describe the clinical characteristics, management, and outcomes of patients with heparin-induced thrombocytopenia with thrombosis (HITTS) or without thrombosis (HIT) who also had an elevated baseline activated partial thromboplastin time (aPTT) due to antiphospholipid antibody syndrome (APS). CASE SUMMARY: Four patients with HIT/HITTS and an elevated baseline aPTT due to APS were identified. Two patients had venous thrombosis, 1 had limb ischemia, and 1 had isolated HIT All 4 were managed with a weight-based fixed dose of argatroban without laboratory monitoring. None of the patients had thrombotic or bleeding complications once therapy was initiated. DISCUSSION: Management of patients with HIT/HITTS and an abnormal baseline aPTT due to APS is problematic. We review alternative management strategies, such as monitoring direct thrombin inhibitors with the ecarin clotting time or thrombin inhibition time or using an alternative anticoagulant, such as fondaparinux. As of March 13, 2006, none of these management strategies has been evaluated in a clinical trial for this patient population. We report the successful use of weight-based, fixed-dose argatroban without laboratory monitoring in patients with APS. CONCLUSIONS: Use of a fixed-dose argatroban regimen without laboratory monitoring is a potential management strategy for patients with HIT/HITTS and an elevated baseline aPTT due to APS.