Hypertension in end-stage renal disease

Treatment of terminal renal failure in children by home dialysis and transplantation

Eleven children, aged 6 to 17 years, suffering from irreversible renal failure, were treated by regular haemodialysis. This was preparatory to renal transplantation in 6 children. During periods of 8 to 26 months none of these patients have died. Both regular haemodialysis and transplantation present unsolved problems. With dialysis, the relation between the diet, amount of dialysis, growth, and sexual development have still to be worked out. With transplantation, better ways of achieving good and controlled immunosuppression must be found. In both types of treatment, the psychological and social trauma to both the patients and their families must be evaluated and treated.

Hemodynamics of uremic anemia

This study was undertaken to assess the importance of an elevated cardiac output in the generation of the hypertension associated with chronic renal failure. Forty stable uremic patients on a program of maintenance hemodialysis underwent hemodynamic studies. Cardiac index measured by dye dilution was found to be significantly elevated. Calculated peripheral vascular resistance was normal despite elevated blood pressure. Six patients underwent serial hemodynamic studies over a period of 6 to 12 weeks while being transfused with packed red blood cells to a normal hematocrit. Blood volume and body weight were constant during the study period. Cardiac index decreased during transfusion, reaching a normal level at a hematocrit of 30%. Diastolic blood pressure progressively rose, averaging an increase of 20 mm Hg at a hematocrit of 40%. Peripheral vascular resistance increased by 80% at a hematocrit of 40%.

We concluded that the elevation of cardiac index in uremic patients is secondary to anemia and is reversible when the hematocrit is raised over 30%. The high cardiac index is not responsible for hypertension because restoration of cardiac index to normal by transfusion raises blood pressure rather than lowers it.

Relevance of salt, water, and renin to hypertension in chronic renal failure

Blood pressure control was examined in 75 patients with end-stage renal failure treated by regular twice-weekly haemodialysis. Dietary sodium was restricted and extracellular fluid was removed by ultrafiltration until blood pressure was normal or signs of salt depletion were observed. Failure of these measures constituted an indication for nephrectomy. Of the 75 patients, 18 were never hypertensive, 46 had hypertension which could be corrected by salt and water depletion, and 11 had persistent hypertension which could not be controlled in this way. Nine of these 11 patients underwent bilateral nephrectomy; in each of the seven in whom the post operative result could be evaluated the blood pressure returned rapidly to normal.Plasma renin activity, measured in 34 subjects, was raised above normal in six out of nine patients whose blood pressure could not be controlled by salt and water depletion and in one of the 11 patients whose blood pressure could be so controlled, but was within the normal range in all nine normotensive patients. The mean level of plasma renin activity in the first group was significantly higher than that of each of the other two groups.There was a significant correlation between hypertension during dialysis and after transplantation, suggesting that, in addition to renin, there is a non-renal factor which predisposes certain patients to hypertension in the presence of salt and water excess.