Heparin-induced thrombocytopenia in patients administered heparin solely for hemodialysis

Background. Heparin, universally used in patients on dialysis, is the cause for immune-mediated heparin-induced thrombocytopenia (HIT). Methods. From an HIT registry, six patients were identified who received recent heparin solely for dialysis, developed HIT, and were treated with argatroban. Platelets counts, aPTTs, argatroban dosing, and outcomes were assessed. Results. Before HIT was diagnosed, unfractionated heparin was used in doses of 2,000-12,000 units. The mean platelet count fell from 122 +/- 62 x 10(9)/L to 35 +/- 22 x 10(9)/L, and one patient experienced thrombosis. After HIT was diagnosed, heparin was discontinued, and argatroban therapy (mean dose, 1.7 +/- 0.9 mu g/kg/min) was administered for 6.5 +/- 4.5 days (mean aPTT, 66.1 +/- 12.4 s). Patients continued on renal replacement therapy. Platelet counts increased during argatroban therapy. A 37-day composite endpoint of death, amputation, or new thrombosis occurred in four (66.7%) patients: three patients died from causes unrelated to thrombosis, and one patient developed new thrombosis after argatroban was discontinued. One patient experienced a hematocrit drop during treatment without overt bleeding or a need for transfusion. Conclusions. HIT can occur in patients administered heparin solely for hemodialysis. When HIT is suspected, heparin should be discontinued and an alternative anticoagulation initiated. Argatroban, which is not renally cleared, supports continued renal replacement therapy in HIT patients.