In uremic patient treated by hemodialysis (HD), a law potassium intake and
a salt load due to diet and or a high sodium concentration in dialysat are
often associated to refractory hypertension. Numerous reports in general po
pulation, based on epidemioologic and demographic data, have pointed to the
relationship between sodium intake and hypertension. The degree of blood p
ressure fall in patients who have evidence of salt-sensitivity varies direc
tly with the severity of the hypertension, being most prominent in those wi
th higher pressures. Recent studies have suggested that a reduction of dial
ysate sodium can control hypertension in maintenance haemodialysis patients
. In this study, five hypertensive haemodialysis patients were assigned to
a regime of lowering the dialysate sodium concentration from 142 to 135 mmo
l/L in combination with an attempt to lower salt intake by advising the pat
ients to eat a NaCl-restricted diet of no more than 6-8 g/day. During the p
eriod under study, dialysis time was kept constant. A significant increase
of ultrafiltrate sodium concentration was observed during the first week af
ter lowering the dialysate sodium concentration. Post dialysis systolic and
diastolic pressures showed a clear trend to fall (systolic pressure 174+/-
18 vs 118+/-13 mmHg, diastolic pressure 96+/-7 vs 75+/-3 mmHg) without a ch
ange of dry weight. The reduction of the mean arterial pressure on 48 h was
demonstrated with ambulatory blood pressure recording. The results of this
study suggest that reducing the dialysate sodium concentration lead to a d
ecrease in peripheral resistance. A link between sympathetic overactivity a
s it is found in haemodialysis patients and sodium load could be a stimulat
ing hypothesis.
It is concluded that increasing dialysate sodium in short dialysis is respo
nsible for the high prevalence of arterial hypertension often insufficientl
y controlled by antihypertensive medication. In hemodialysis patients with
refractory hypertension, the lowering of the dialysate sodium concentration
is indicated.