Homozygous familial hypercholesterolemia. Selective removal of low- density lipoproteins by secondary membrane filtration

Selective plasma filtration with a hollow-fiber membrane device was compared prospectively to plasma exchange in the therapy of a patient with homozygous familial hypercholesterolemia. Four liters of patient plasma was removed biweekly during each of six consecutive plasma exchanges, after which 20 consecutive biweekly 4-liter filtration procedures were conducted. The hollow-fiber membrane retained 94 percent of the low-density lipoprotein (LDL) cholesterol presented to it, and allowed passage of 83 percent of the albumin, 68 percent of the IgG, and 47 percent of the high-density lipoprotein (HDL) cholesterol. Both plasma exchange and plasma filtration decreased the patient's total and LDL cholesterol levels by 80 percent. However, filtration removed significantly less HDL than did exchange (54 versus 71% reduction in HDL levels, respectively); preserved significantly higher levels of IgG, clotting factors, and complement components; and avoided the need for expensive albumin replacement solutions. In addition, the patient tolerated the filtration procedures significantly better than the exchanges. Newer apheresis techniques that selectively deplete plasma of LDL cholesterol, such as secondary membrane filtration, are likely to replace plasma exchange as the therapy of choice in patients with homozygous hypercholesterolemia.