NO GENERATION OF BRADYKININ WITH A NEW POLYACRYLONITRILE MEMBRANE (SPAN) IN HEMODIALYSIS-PATIENTS TREATED WITH ACE-INHIBITORS

Background. Anaphylactoid reactions occurring in uraemic patients haem odialysed with polyacrylonitrile haemodialysis (HD) membranes and bein g treated with ACE inhibitors have been attributed to an excessive gen eration of bradykinin. Methods. Here we tested in a prospective trial a new type of polyacrylonitrile membrane (SPAN) with respect to bradyk inin generation in nine HD patients receiving either captopril or enal april. Each patient had three consecutive HD sessions with each of the three tested membranes, high-flux SPAN, high-flux polysulphone (F60) and low-flux Hemophan (GFS Plus 16). Results. No clinical signs of ana phylactoid reactions were observed in any of these patients but the nu mber of patients was relatively small and the duration of exposure to different membranes relatively short. At 5 min after the start of HD s ession, plasma bradykinin levels were significantly higher in the veno us than in the arterial line for all three HD membranes: SPAN, 18.5 +/ - 11.9 versus 12.4 +/- 5.3 fmol/ml (P < 0.05); F60, 19.0 +/- 13.8 vers us 11.5 +/- 6.5 fmol/ml (P < 0.01); and GFS Plus 16, 39.1 +/- 22.9 ver sus 15.8 +/- 12.4 fmol/ml (P < 0.005), mean +/- SD respectively. Highe r venous line levels were still observed at the 15 and 60 min time poi nts for F60 and GFS Plus 16, but not for SPAN. However, these levels w ere still insignificant compared to levels measured during episodes of anaphylactic shock from the literature. Plasma histamine and C5a anap hylatoxin levels did not show any increase during HD with SPAN.Conclus ion. The SPAN membrane did not induce significant bradykinin release i n dialysis patients on ACE-inhibitor therapy. It may therefore be used for high-flux dialysis in such patients.