Synthetic modification of PAN membrane : biocompatibility and functional characterization

A disturbing interaction of PAN membranes and the bradykinin generation system particularly in the presence of angiotensin converting enzyme inhibitors has been described. A modified new membrane, SPAN (special PAN), was produced by varying the polymer components in type and composition, in particular by a reduction in Na-Methallylsulfonate. Although the SPAN membrane successfully averted the bradykinin generating ability of PAN, it was important to determine whether such a modification did not lead to a loss of the satisfactory biocompatibility profile characteristic of the parent membrane. For this purpose, we conducted the present clinical study in nine patients comparing 3 membranes; (i) a polysulphone membrane (F60S); (ii) PAN; and (iii) SPAN, to examine the clinical biocompatibility profile and performance of the new membrane. A small increase in C5a with F60S and SPAN was found which is in the range expected for highly biocompatible synthetic membranes. The three dialysers had a similar inert profile for terminal complement complex arterial values, and had similar venous values. A minimal nonsignificant decline in white cell count was observed at 15 min for all dialysers, but otherwise WBC counts were unchanged. Platelet counts were unchanged throughout treatment for the three dialysers. Arterial and venous thrombin-anti-thrombin complex values were similar for all three dialysers. F60S and SPAN dialysers had similar urea clearances.