Advantages of new hemodialysis membranes and equipment.

Chronic kidney disease is characterized by the progressive retention of a number of compounds, several of which have the potential to cause cardiovascular damage. Many of these are difficult to remove by standard dialysis strategies. Removal of the larger middle molecules (mostly larger peptidic compounds) can be obtained by increasing dialyzer pore size and/or by applying convective strategies. For protein-bound solutes, convection (essentially hemodiafiltration) positively affects removal. The HEMO study demonstrated outcome superiority for the large-pore high-flux hemodialysis membranes in a number of subgroup analyses. Likewise, the Membrane Permeability Outcome study showed outcome superiority for high flux in patients with serum albumin <4 g/dl, the group for which the study had originally been designed. Apart from a small controlled trial, data suggesting superiority for convective strategies are all observational.