THE EFFECT OF HYPONATREMIC VERSUS ISONATREMIC DIALYSATE IN PATIENTS WITH INTRADIALYTIC HYPERTENSION

Objective: Intradialytic hypertension (IDH) is a commonly, but poorly understood and studied phenomenon in hemodialysis (HD) patients. To determine the prevalence of IDH in a prevalent HD population and their characteristics. To evaluate the effect of individually adjusted iso- and hyponatremic dialysate on IDH, intra- and interdialytic blood pressure (BP), weight gain and side effects in patients with IDH. Design and method: Cross-sectional study, followed by a prospective, randomized, cross-over study with 4 consecutive 4-week periods with different dialysate sodium concentrations in patients with IDH. During run-in and wash-out standard dialysate (140 mmol/l) was prescribed. Office BP was measured standardized with an automated device during dialysis; home BP was evaluated by 24 h ambulatory BP measurement and by self-measurement using a BP telemonitoring system. Results: Prevalence of IDH was 11.9% (n = 13/109). Subjects with IDH were older, had lower dry weight, lower interdialytic weight gain and weretaking more antihypertensive drugs. During iso- and hyponatremic treatment, resp. 42% and 40% of dialysis sessions were complicated by IDH compared to 51% during run-in (NS). During standard dialysate office post-HD BP, 24 h ambulatory BP and tele-HBP were resp. 159 +/- 22/80 +/- 12 mm Hg, 144 +/- 21/75 +/- 11 mm Hg and 156 +/- 25/84 +/- 16 mmHg. Compared to standard dialysate, both hypo- and isonatremic dialysate significantly decreased post-HD BP (p < 0.005). Office post-HD BP and 24 h ambulatory BP were lower during hyponatremic dialysis compared to isonatremic dialysate, but without reaching significance (resp. 142 +/- 21/73 +/- 13 vs 154 +/- 25/77 +/- 14 mmHg and 134 +/- 33/71 +/- 15 vs 144 +/- 28/74 +/- 12 mmHg). Tele-HBP revealed only minimal changes in BP. Interdialytic weight gain did not differ significantly between hypo- and isonatremic dialysis (1.464 +/- 0.818 kg vs1.609 +/- 0.978 kg), the prevalence of side effects was similar too (resp. 8 and 9%). Conclusions: Individualized lowering of dialysate sodium did not result in a significant reduction of IDH episodes. However, both iso- and hyponatremic dialysate significantly lowered office BP compared to standard dialysate, interdialytic BP tended to decrease. Lowering dialysate sodium did not increase intradialytic side-effects.