The current state of extracorporeal haemorheotherapy: from haemodilution via cascadefiltration to rheohaemapheresis

Rheological therapy aims at an improvement of organ perfusion however, it h as to be stressed that the tonus of the blood vessels also plays an importa nt role for both the blood distribution and the theology in the micro- and the macrocirculation. Conventional rheotherapy consists of attempts to infl uence nutrition and life style, to apply drugs such as purin derivatives, v asodilatating or defibrinising substances and hypervolaemic (using infusion therapy), hypovolaemic, e.g., blood letting, erythrocytapheresis and - the most widely distributed - isovolaemic haemodilution. With the introduction of centrifugal devices, and approximately 10 years later with the introduc tion of hollow fibre and flat sheet membrane techniques, a considerable inc rease of therapeutical efficacy was achieved. These technologies were succe ssfully applied for the treatment of cellular and plasmatic hyperviscosity syndromes. The treatment of less severe diseases of the micro- and macrocir culation, vessel stenosis, vessel wall sclerosis, malformation of the blood vessel architecture, pathological clinical-chemical blood parameters and m aldistribution have hardly been taken into consideration. Our group at Koln investigated different plasma differential separation techniques and demon strated, that adsorption as well as filtration could be applied. These diff erent techniques being 6-10 times more effective as conventional haemodilut ion techniques have in common high molecular weight proteins determining th e viscosity of plasma and thus whole blood viscosity is removed, however di fferences among the different elimination techniques do exist. The theologi cal and clinical importance of such differences has to be determined. Apply ing filtration techniques for both primary and secondary separations, the c oncept of Rheohaemapheresis was developed. A corresponding quality program was also introduced into our clinical routine. Rheohaemapheresis is support ed from the currently introduced concept of the synergetic consideration of the microcirculation. Age related macular degeneration, so Far without gen erally accepted therapy, is a most advanced indication based on several pil ot studies and a prospective, randomised controlled trial. Other diseases o f the microcirculation have also successfully been treated. (C) 2001 Elsevi er Science Ltd. All rights reserved.