An examination of the anticoagulant regimen in a patient with thrombotic thrombocytopenic purpura undergoing a combination of plasma exchange and hemodialysis

Abstract

We examined the dosage of anticoagulant given to a patient with thrombotic thrombocytopenic purpura (TTP) undergoing a combination of plasma exchange (PE) and hemodialysis (HD). The patient was a man in his seventies in whom HD was initiated for acute kidney injury in September 2011 and PE was initiated following a diagnosis of TTP in October of the same year. Due to the delirium symptoms, the patient underwent a combination of PE and HD 25 times from November 2011 to shorten his treatment time. The circuit was configured with the HD circuit as the base and the PE circuit was connected in a quasi-series before HD. Nafamostat mesylate (NM) was used as an anticoagulant. Activated clotting time (ACT) was measured and compared (1) before the plasma separator, (2) after the plasma separator, and (3) at the dialyzer outlet when NM was administered at 30mg/h from both the PE and HD circuits and when NM was administered at 30 mg/h from the PE circuit alone. Results revealed that ACT at the dialyzer outlet was approximately 330 s on an average irrespective of the NM dosage. In addition, no coagulation was observed within the circuit. The patient was safely treated with a reduced dosage of anticoagulant by combining PE and HD.