Glomerular spherical electron dense deposits in a patient undergoing long-term regional heparinization

Spherical electron dense deposits in the glomerular capillary basement membranes and the mesangial matrix were observed in a patient undergoing long-term regional heparinization during treatment with continuous arteriovenous hemofiltration (CAVH). CAVH is a fairly new approach to renal replacement therapy and requires continuous infusion of heparin into the prefilter blood line. In order to limit systemic anticoagulation, protamine may be infused into the postfilter blood line. In the patient described, during 26 days of continuous treatment, 318,620 units of heparin and 5,204 mg of protamine had been infused. Ultrastructural studies of the kidneys obtained at autopsy revealed a striking resemblance between the electron dense deposits seen in this patient and the protamine-heparin complexes described in animal models. Heavy metals, including calcium, phosphorus, and aluminum were excluded by electron probe x-ray microanalysis.