Evaluation of albumin loss during low-density lipoprotein apheresis

Because the reduced plasma oncotic pressure from hypoproteinemia causes hyperlipidemia, serum albumin levels should be maintained during low-density lipoprotein (LDL) apheresis. The amount of albumin loss was evaluated in seven patients with familial hypercholesterolemia during LDL apheresis in which columns packed with dextran sulfate-cellulose beads were used as a selective adsorbent of LDL. Serum albumin level significantly decreased from 4.3 +/- 0.3 (mean +/- SD) g/dl to 3.6 +/- 0.2 g/dl. The albumin loss was assessed by two different methods: 1) radioimmunoassay of microalbumin content in the discarded fluid, and 2) measurement of changes in plasma albumin reserve. The albumin losses during one apheresis session were 3.7 +/- 2.9 g and 8.3 +/- 5.7 g, respectively, depending upon which of two different methods was used. There was a significant correlation between these two methods (r = 0.84, p less than 0.02). The amount of albumin loss during apheresis was estimated to be between 4.1% and 9.1% of total plasma albumin reserve, and more than half of the decreased serum albumin level appeared to be attributable to dilution due to the electrolyte solution used for priming of the extracorporeal circuit.