Therapeutic effects of the long-term use of PAN membrane dialyzer in hemodialysis patients: efficacy in old dialysis patients with mild PAD.
BACKGROUND
AN69 dialyzer, a plate type dialyzer with a polyacrylonitrile membrane (PAN membrane) is reported to reduce symptoms in hemodialysis (HD) patients with complications such as poor nutritional status and peripheral arterial disease (PAD). Yet very few studies have investigated the long-term use of the PAN membrane or compared the solute-removal properties of the PAN membrane with those of the Type IV polysulfone membrane (PS membrane), the dialysis membrane most widely used. In the present study we compared the contaminant-removal properties of the AN69 membrane dialyzer with those of a Type IV PS membrane dialyzer and investigated the clinical effects of the long-term use of the former for elderly hemodialysis patients with mild PAD.


METHODS
Cross-over trials with 2 week intervals for solute were conducted in 6 patients to compare the performance of the membranes in removing small molecular weight substances, β2 microglobulin (β2MG), amino acid (AA), and serum albumin (Alb). Next, the AN69 membrane was used for dialysis over a period of 72 weeks in 8 patients. The time course changes of Alb, the geriatric nutritional risk index (GNRI), the % creatinine generation rate (%CGR), the normalized protein catabolic rate (nPCR) and the dry weight (DW) were observed to evaluate the nutritional status. The time course changes of β2MG, C-reactive proteins (CRP), LDL cholesterol (LDL), fibrinogens (Fib), nitrogen oxide (NOx), hemoglobin (Hb), ferritins, transferrin saturation (TSAT), dose of erythropoiesis-stimulating agents (ESA), and dose of iron were observed to evaluate the therapeutic effects of long-term use. Skin perfusion pressure (SPP) was measured at two points: once at the switchover to the AN69 membrane and once 72 weeks later.


RESULTS
In cross-over trials, the AN69 membrane showed basically the same dialysis efficiency as the PS membrane in removing small molecular weight substances, but it removed significantly lower amounts of β2MG. The AN69 membrane also showed significantly lower rates of AA removal rate and Alb leakage. The nutritional status was stably maintained during long-term use after the switchover to the AN69 membrane, and no significant increase of β2MG was observed. Fib and NOx were both reduced, the latter to a significant degree. The Hb values showed a good time course, with relatively high TSAT levels and low ferritin levels overall. SPP remained generally stable for 72 weeks.


CONCLUSION
The cross-over trial show the AN69 membrane eliminates less AA and Alb compared with the PS membrane. Judging from the therapeutic effects of the long-term use of the AN69 membrane, the membrane is effective for dialysis and has good biocompatibility in the treatment of elderly HD patients with mild PAD.