Argatroban and renal replacement therapy in patients with heparin-induced thrombocytopenia.
BACKGROUND: Argatroban, a direct thrombin inhibitor, is an effective anticoagulant for patients who have heparin-induced thrombocytopenia (HIT). Anticoagulation is usually required for renal replacement therapy (RRT). OBJECTIVE: To prospectively evaluate the pharmacokinetics, pharmacodynamics, and safety of argatroban during RRT in hospitalized patients with or at risk for HIT. METHODS: Five patients with known or suspected HIT underwent hemodialysis (n = 4) or continuous venovenous hemofiltration (CVVH, n = 1), while receiving a continuous infusion of argatroban 0.5-2 microg/kg/min. Activated partial thromboplastin times (aPTTs), activated clotting times (ACTs), argatroban concentrations (plasma, dialysate, CVVH effluent), and safety were assessed before, during, and after a 4-hour session of RRT. Systemic and dialytic argatroban clearances were calculated. RESULTS: Among the 4 hemodialysis patients, aPTT, ACT, and plasma argatroban concentrations remained stable during RRT, with respective mean +/- SD values of 74.3 +/- 34.2 seconds, 198 +/- 23 seconds, and 499 +/- 353 ng/mL before RRT, and 70.6 +/- 21.4 seconds, 181 +/- 12 seconds, and 453 +/- 295 ng/mL 2 hours after starting RRT (p values NS). Systemic clearance was 17.7 +/- 12.8 L/h before hemodialysis and 17.0 +/- 9.5 L/h during hemodialysis (n = 2). The dialyzer clearance (dialysate recovery method) was 1.5 +/- 0.4 L/h (n = 4). Generally similar responses occurred in the CVVH patient: systemic argatroban clearance was 4.8 L/h before CVVH and 4 L/h during CVVH. The hemofilter argatroban clearance was 0.9 L/h. No bleeding or thrombosis occurred. CONCLUSIONS: Argatroban provides effective alternative anticoagulation in patients with or at risk for HIT during RRT. Argatroban clearance by high-flux membranes during hemodialysis and CVVH is clinically insignificant, necessitating no dose adjustment.