Kinin kinetics during different dialysis protocols with AN69 dialyser in ACEI-treated patients

The effect of different dialysis modes on kinin kinetics was studied in seven stable haemodialysis patients treated with AN69 dialysers and ACE inhibitors (ACEI). AN69 haemodiafiltration with calcium-enriched substitution (HDF), AN69 haemodialysis with 1.75 (HD 1.75) and 1.50 (HD 1.50) mmol/l dialysate calcium, AN69 haemodialysis with 1.25 mmol/l dialysate calcium and substitution of 2.25 mmol/h calcium (HD+Ca), and cellulose acetate haemodiafiltration (CA HDF) were compared. Dialysis was uneventful in all patients. During dialysis, serum calcium, sodium, pH, albumin, and bradykinin were measured at the start and after 5 min at arterial, venous, and postinfusion side of the extracorporeal circuit. Serum predialysis bradykinin was 107 +/- 18fmol/ml (mean +/- SEM) in patients on HDF, 61 +/- 9 fmol/ml in patients on HD 1.50, 49 +/- 13 fmol/ml in patients on HD 1.75, 35 +/- 3 fmol/l in patients on HD+Ca, and 75 +/- 27 fmol/ml in CA HDF. No significant change of mean bradykinin levels occurred after 5 min at the arterial and venous side of the dialyser or postinfusion. Individual high bradykinin levels, up to 2672 fmol/ml, were observed but without clinical consequences, suggesting that the threshold value is difficult to determine. No significant correlations were evidenced between bradykinin levels and any of the biochemical measurements. The present data show an intraindividual variability of the bradykinin levels with variation coefficients ranging from 0.386 to 2.783. The present study illustrates that haemodialysis and haemodiafiltration with AN69 in ACEI-treated patients, under the present conditions, does not result in anaphylactoid reactions or in a clinically significant release of bradykinin.