Resolution of restless legs syndrome after postdilution online hemodiafiltration using a vitamin E-bonded polysulfone membrane: a report of two cases.

Two patients undergoing hemodialysis with long-standing, refractory restless legs syndrome were treated with pharmacologic therapy and high-efficiency online hemodiafiltration, achieving an α1-microglobulin removal rate of ≥ 40%. However, sufficient symptom improvement was not achieved. Therefore, online hemodiafiltration using a vitamin E-bonded polysulfone membrane, which has antioxidant effects, was introduced. Although only limited improvement was observed during predilution online hemodiafiltration, marked clinical benefit was obtained after switching to postdilution online hemodiafiltration. In both cases, the α1-microglobulin removal rates after initiation of postdilution online hemodiafiltration were below 40%. These findings suggest that high-efficiency α1-microglobulin removal and the use of a vitamin E-bonded polysulfone membrane may contribute to improvement in restless legs syndrome through distinct mechanisms. Additionally, the beneficial effect of a vitamin E-bonded polysulfone membrane may be affected by differences in the dilution mode during hemodiafiltration. This case report is the first to indicate that the use of a vitamin E-bonded polysulfone membrane during postdilution hemodiafiltration may represent a potential new therapeutic option for restless legs syndrome.