refludan and Aortic-Dissection

Heparin-induced thrombocytopenia with thrombosis (HITT) is a rare complication of cardiac surgery with cardiopulmonary bypass. We report two cases of HITT treated with the direct thrombin inhibitor Lepirudin. Immediate diagnosis was essential to prompt heparin discontinuation and successful early Lepirudin administration in the first case. In the second, the presence of an intra-aortic balloon pump delayed HITT recognition, and Lepirudin infusion could not prevent limb amputation. In both cases HITT occurred earlier (< 5 days after heparin exposure) than its usual presentation.

Topics: Adult; Aged; Amputation, Surgical; Anticoagulants; Aorta; Aortic Aneurysm; Aortic Dissection; Aortic Valve; Blood Vessel Prosthesis Implantation; Combined Modality Therapy; Coronary Artery Bypass; Early Diagnosis; Fibrinolytic Agents; Heart Valve Prosthesis Implantation; Heparin; Hirudins; Humans; Intra-Aortic Balloon Pumping; Ischemia; Leg; Male; Marfan Syndrome; Mitral Valve; Postoperative Complications; Recombinant Proteins; Thrombocytopenia; Thrombophlebitis

A 60-year-old man was admitted to the hospital with aortic dissection. An operative excision and replacement with a Y-graft was performed. Postoperatively he developed multiple organ dysfunction and required intermittent haemofiltration (anticoagulation with heparin). An ischemia of the left leg occurred at the third postoperative day. The initial platelet count was 99,000/microliter. Continuous haemofiltration (CVVH) was started three days later. Thrombotic obstructions of haemodialysis filters and catheters occurred frequently and heparin-induced thrombocytopenia (HIT II) was suspected. Antibodies against heparin were found in the HIPA test. Despite heparin free citrate dialysis and anticoagulation with danaparoid thrombotic obstructions of filters and catheters continued. Therefore the anticoagulation therapy during CVVH was changed to recombinant hirudin (lepirudin). Starting dose was a bolus of 0.01 mg/kg bw followed by the same amount as maintenance dose per hour. Anticoagulation was adjusted to an increase of aPTT (activated partial thromboplastin 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 changing to lepirudin no further catheter obstructions were observed and the platelets recovered slowly. Renal function improved and five weeks after admission endogenous creatinine clearance showed a value of 25 ml/min. We conclude that lepirudin is an effective anticoagulant during CVVH in patients with HIT II. In partly permeable polysulfon filters a dose of 0.005 mg/kg bw/h lepirudin is sufficient to maintain adequate anticoagulation. Monitoring 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.

Topics: Anticoagulants; Aortic Aneurysm, Abdominal; Aortic Dissection; Blood Vessel Prosthesis Implantation; Hemodiafiltration; Heparin; Hirudin Therapy; Hirudins; Humans; Male; Middle Aged; Multiple Organ Failure; Recombinant Proteins; Thrombocytopenia; Treatment Outcome