**6. Conclusions**

The outlook of more biocompatible and physiological dialysis is today confronted with a older and sicker population in need of maintenance HD. The knowledge of biological mechanisms operating at the system level will be approached with the help of improved technologies hopefully able to reduce the deleterious effect of the repetitive contact with a foreign surface and to insure optimal performances for the elimination of small and middle molecule solutes. Advances in dialyzer membranes and geometries, as well as blood tubings together with new concepts in machine technology have already shown their great potential to improve survival and cardiovascular stability.
