Blood pressure on dialysis: an ongoing controversy.
Based on apparently conflicting epidemiological data there has recently been considerable uncertainty and controversy concerning optimal blood pressure (BP) levels in patients on maintenance hemodialysis. It has also become obvious that it is not only the mean arterial pressure, but also the arterial pulse pressure profile, which impacts on hemodynamic stress and outcome. Epidemiological surveys document that, in the pre-dialysis state, up to 53% of chronically dialyzed patients have systolic BP above 140 mm Hg, but only 17% have diastolic BP values above 90 mm Hg. In other words, the systolic BP tends to be elevated, while the diastolic BP remains within normal limits. This constellation reflects the reduced elasticity of central arteries leading to increased pulse wave velocity and larger BP amplitude. Recent retrospective surveys created much uncertainty: they indicated that short-term survival was optimal when predialysis systolic BP values were between 130 and 180 mm Hg, higher values conferring little additional risk. In contrast, the risk of death was increased dramatically for BP values below 120 mm Hg. According to epidemiological studies in the general population, patients with low systolic BP are characterised by poor cardiac function and high cardiac risk. It has been observed that after such high-risk patients have died, in the long run, a continuous positive relationship exists between BP and survival. These observations are in agreement with what has also been observed in dialysis patients by Charra (Tassin, France). We are of the opinion that, in general, a pre-dialysis systolic BP in the low normal range is optimal for survival. This goal may not be achieved in all patients and may cause side effects so that it is necessary to individualize the approach. Rapid ultrafiltration carries the risks of sympathetic activation and intradialytic hypotension, which must be avoided. Relatively simple measures are effective in lowering blood pressure, e.g. low salt intake, reduction of dialysate sodium concentration, long slow and possibly more frequent dialysis sessions.
Ritz
Eberhard
E
Department of Internal Medicine, Ruperto Carola University of Heidelberg, Germany.
Pablick-Deetjen
Jutta
J
Zeier
Martin
M
Amann
Kerstin
K