SP474
IMPACT OF SODIUM PROFILING IN HEMODIALYSIS AND HEMODIAFILTRATION ON RENIN LEVELS OF PATIENTS WITH END STAGE RENAL DISEASE

INTRODUCTION: Patients with end stage renal disease show activation of the renin-angiotensin-aldosterone (RAAS) axis in comparison to controls with normal kidney function. This activation is often further increased during extracorporeal dialysis due to decreased intravascular volume during the ultrafiltration process.

The aim of this study was to investigate the impact of sodium profiling during hemodialysis (HD) and hemodiafiltration (HDF) on renin levels.

METHODS: Adult patients with end stage renal disease on chronic thrice weekly program of HD or HDF were included in the study. Patients treated with RAAS inhibitors were excluded. Direct plasma renin levels were measured (at the beginning and at the end of the four-hour session) during two different mid-week dialysis sessions (standard sodium session and sodium profiling session), one week apart. During the standard sodium session dialysate sodium concentration of 140 meq/l was applied, while during the sodium profiling session, sodium dialysate concentration ranged from 140 meq/l at the beginning and was gradually decreased to 138 meq/l during the last hour of dialysis. Basic patients' clinical and laboratory characteristics were also evaluated as well as ultrafiltration and hypertension values during the two dialysis sessions. Dialysis conditions were kept the same for all the examined sessions.

RESULTS: Seventeen patients were recruited for the study (9 on HD and 15 men) with a mean age of 58,7 ± 14,6 years. Mean ultrafiltration volume did not differ significantly between standard and sodium profiling dialysis (HD and HDF) (1869 ± 656 vs. 1767 ± 888 ml, respectively, p=ns). Plasma renin levels were significantly increased during standard dialysis (25,1 ± 31,6 vs. 29,9 ± 37 ng/ml, p=0,047) while were decreased during sodium profiling dialysis (27,85 ± 24,4 vs. 26,6 ± 25,9 ng/ml, p=ns). ΔRenin (the difference of plasma renin levels at the end and beginning of the dialysis session) was also examined between standard and sodium profiling dialysis (4,82 ± 8,9 vs. -1,23 ± 8,6 ng/ml respectively, p=0,019). When ΔRenin was examined in HD and HDF separately for standard and sodium profiling dialysis, a greater difference was observed during HDF (7,6 ± 8,8 vs. 2,1 ± 9,8 ng/ml, p=ns for HD and 1,68 ± 8,5 vs. -5 ± 5,3 ng/ml, p=ns for HDF).

CONCLUSIONS: Direct plasma renin levels are reduced during dialysis when sodium profiling is applied. This effect is independent of ultrafiltration volume. Hemodiafiltration in comparison to hemodialysis leads to greater plasma renin reduction.