Plasmapheresis by Using Secondary Membrane Filters: Twelve Years of Experience

Over 1,600 plasmapheresis procedures have been performed by using secondary on-line membrane plasma filters in 62 patients over the past 12 years in our institution. The disease categories treated include cryoprotein induced diseases such as cryoglobulinemia, immune mediated disorders, and familial type II-A hypercholesterolemia (FHC). Depending upon the molecular size of the offending agent, we used plasma filters (PF) with different pore sizes ranging from 0.02 μm to 0.04 μm or the cryoglobulin filter (CF) with an average pore size of 4.3 μm to remove cryoprecipitable proteins. One plasma volume was processed in each treatment. The results of treating 25 patient in over 550 procedures by using PF show it is safe and effective in treating immune mediated disorders and FHC. PF selectively removes macromolecules according to pore size and are more specific for the treatment of immune mediated diseases and FHC than plasma exchange. The results of treating 37 patients in over 1,100 procedures by using CF show it is safe and effective in selectively removing cryoproteins, and it is very specific for the treatment of cryoprotein induced diseases. Both PF and CF are biocompatible, with no complement activation. Unlike plasma exchange, secondary membrane plasma filters do not cause deficiency syndromes and do not require albumin or fresh frozen plasma as replacement fluid, making them more cost effective than plasma exchange.