Hemodialysis-associated platelet loss: study of the relative contribution of dialyzer membrane composition and geometry.

To evaluate the relative contribution that dialyzer membrane composition and geometry make to hemodialysis-associated platelet loss, the effect of a single dialysis with three different types of dialyzers on platelet count was examined on a cross-over basis in 19 uremic patients on maintenance hemodialysis. Also, the plasma levels of antithrombin-iii before and after dialysis were measured, but no significant variations were found regardless of which dialyzer was in use. Our patients suffered significant platelet loss during cuprophan dialysis, but not polyacrylonitrile dialysis. More than 99% of initial circulating platelets were recovered at the end of polyacrylonitrile dialysis, whereas cuprophan dialysis did leave a significantly lower percentage of circulating platelets (p less than 0.05). The internal comparison of results obtained with the two cuprophan dialyzers used shows no difference as to the dialyzer geometry (flat plate or hollow fiber). This indicates that the membrane composition is the major factor influencing hemodialysis-associated platelet loss. We suggest that patients with low platelet count and/or with risk of bleeding may benefit from polyacrylonitrile dialysis.