Selective removal of low density lipoprotein by plasmapheresis in familial hypercholesterolemia

Plasma lipoproteins were selectively removed from familial hypercholesterolemic patients by using two types of plasmapheresis: double-membrane filtration and selective adsorption of very low density lipoproteins (VLDL) and low density lipoproteins (LDL). In both techniques, plasma was separated from blood cells by using hollow-fiber filters, and 100% of the VLDL and LDL was recovered in the filtrate. In double-membrane filtration, the second hollow-fiber filter trapped 84% of LDL + VLDL, 48% of high density lipoprotein (HDL), 24% of albumin, and 46% of the remaining plasma protein. By treating 3 liters of plasma from a patient weighing 60 kg, 60% of the LDL and 30% to 40% of the HDL were removed as a result of an exponential decay of each component with the respective trapping coefficients. When dextran sulfate-cellulose was used as a LDL sorbent, there was only loss of LDL and VLDL, and no loss of any other major plasma component or of HDL. The sorbent column (400 ml) was saturated with 7.5 g of LDL cholesterol by treatment with 3.5 liters of plasma; the maximum reduction of LDL cholesterol was thus about 300 mg/dl for the patient weighing 60 kg. No serious side effects were observed during the long-term trials (19 to 27 months for four patients on double-membrane filtration and 10 months for the two patients on dextran sulfate-cellulose treatment.