Continuous haemofiltration with r-hirudin (lepirudin) as anticoagulant in a patient with heparin induced thrombocytopenia (HIT II)

A 60-year-old man was admitted to the hospital with aortic dissection. An o perative excision and replacement with a Y-graft was performed. Postoperati vely he developed multiple organ dysfunction and required intermittent haem ofiltration (anticoagulation with heparin). An ischemia of the left leg occ urred at the third postoperative day. The initial platelet count was 99000/ mu l. Continuous haemofiltration (CVVH) was started three days later. Throm botic obstructions of haemodialysis filters and catheters occurred frequent ly and heparin-induced thrombocytopenia (HIT II) was suspected. Antibodies against heparin were found in the HIPA test. Despite heparin free citrate d ialysis and anticoagulation with danaparoid thrombotic obstructions of filt ers and catheters continued. Therefore the anticoagulation therapy during C VVH was changed to recombinant hirudin (lepirudin). Starting dose was a bol us of 0.01 mg/kg bw followed by the same amount as maintenance dose per hou r. Anticoagulation was adjusted to an increase of aPTT (activated partial t hromboplastin time) to 1.5-2 times its normal value. A dose of 0.005 mg/kg bw/h lepirudin was sufficient to maintain adequate anticoagulation. After c hanging to lepirudin no further catheter obstructions were observed and the platelets recovered slowly. Renal function improved and five weeks after a dmission endogenous creatinine clearance showed a value of 25 ml/min. We conclude that lepirudin is an effective anticoagulant during CVVH in pat ients with HIT II. In partly permeable polysulfon filters a dose of 0.005 m g/kg bw/h lepirudin is sufficient to maintain adequate anticoagulation. Mon itoring anticoagulation by measuring the increase of aPTT (factor 1.5-2.0) seems to be safe. However, optimally the r-hirudin concentration should be measured directly using the Ecarin clotting time.