Dietary salt restriction and reduction of dialysate sodium to control hypertension in maintenance haemodialysis patients.

The management of hypertension in patients with end restriction (4–5 g/day) [6 ]. Tassin in France repeatedly stage renal disease on maintenance haemodialysis has reports the best survival and lowest gross and standardchanged completely in the past three decades. In the ized mortality on maintenance haemodialysis in the early 1960s it was possible to control even the severest world. Excellent blood pressure control is achieved hypertension without drugs by the use of a low sodium without drugs with mean arterial pressures below dialysate (130 mmol ) and a restricted salt intake 99 mmHg. A total of 98.4% of patients of the dialysis (<5 g/day). The diet was simple. It required home population in Tassin do not require blood pressure cooking without added salt and the avoidance of medication. However, recently they have not stressed obviously salted foods. Excellent results using this the importance of salt restriction as a requirement for regime were reported from several centres [1,2] and their successful regime. This may account for the bilateral nephrectomy—a procedure which was partial failure to reproduce the favourable results when common practice to treat otherwise resistant renal only the dialysis time has been lengthened and no hypertension—was considered unnecessary by those attention has been paid to salt restriction [7,8]. who practiced this regime [3]. Associated with success Recently, we and others [9,10] have demonstrated were long hours (8 h) of overnight dialysis on a Kiil that it is possible to lower blood pressure and reduce dialyser with a cuprophan membrane. Successful conor even discontinue antihypertensive medication withtrol of hypertension by this technique occurred indeout prolongation of dialysis time (4–5 h per session) pendently of the buffer used in the dialysate. It was and without altering dry body weight. first described with bicarbonate as a buffer [1,2] and In our study, eight hypertensive haemodialysis later also reproduced with acetate-buffered dialysate patients were assigned to a regime of gradual lowering [3]. the dialysate sodium concentration from 140 to In the late 1970s dialysis times were shortened from 135 mmol/l at a rate of 1 mmol/l every 3–4 weeks in three times for 6–8 h a week to three times 3–5 h. High combination with an attempt to lower salt intake by efficiency haemodialysis was introduced, with high advising the patients to eat a moderately NaClblood flow and dialysate flow rates in combination restricted diet of no more than 6 g/day with no added with large surface area dialysers. This regime frequently salt and avoidance of canned and salty tasting food. caused cardiovascular instability during dialysis, Dialysis time was kept constant. Predialysis systolic muscle cramps and post-dialysis hypotension. As a and diastolic pressures showed a clear trend to fall consequence, in order to avoid patient misery with (systolic pressure 147±9.3 vs 136±17 mmHg, diastolic shorter and more efficient haemodialysis, dialysate pressure 88±5.5 vs 80±9.6 mmHg) without a change sodium was raised to 140 mmol/l or more and dietary of dry weight. The reduction of the mean arterial sodium restriction was abandoned. Today, hypertenpressure reached a level of significance (108±4.4 vs sion is an increasing problem in dialysis patients inspite 98±10.9; P=0.02, Wilcoxon test). The antihypertensof a much larger choice of potent antihypertensive ive medication could be reduced significantly as well. drugs [4]. In addition, cardiovascular diseases remain In four out of eight patients blood pressure pills could the most frequent cause of death and life expectancy be stopped completely. However, in only half of the of the dialysis patient has worsened [5]. patients a decrease of interdialytic weight gain could One centre in the world has remained faithful to the be observed indicating only partial compliance with original formula of long hours of dialysis, a relatively the salt restriction. In some patients lowering the salt low sodium dialysate (138 mmol/l ) and dietary salt load had the effect of restoring taste acuity for salt