The role of rheology in hemapheresis.

Rheological therapy attempts to favorably influence the blood flow mechanics for the treatment of diseases, mainly of the microcirculation but also of the macrocirculation. Hemapheresis, originally used only for the elimination of an excess of cellular or plasmatic components, was shown to also influence the hemorheology favorably. As extracorporeal therapy affects the rheology much more than conventional hemorheotherapy, not only cellular or plasmatic hyperviscosity syndromes but also many more diseases associated with organ perfusion problems due to diseases of the micro- and macrocirculation, especially in the elderly, were and are increasingly considered to be indicated. Technical progress led away from plasma exchange as an unspecific and unselective procedure to plasma differential separation using precipitation. adsorption, and filtration. With our recent development, we demonstrated that rheohemapheresis is the most advanced technical procedure. The mechanism of action can well be related to a synergetic consideration of rheology. However. one has to keep in mind that the elimination of blood components such as lipids, immunoglobulins, and endothelial factors may well contribute to the explanation and understanding of the positive clinical effects observed. These speculative aspects need further investigation.