Adequate dialysis with special attention to proper nutrition aimed to achieve the high end of normal BMI may help to reduce the high mortality and morbidity in hemodialysis patients.

No abstract

Abstract-The impact of aldosterone in cardiovascular disease and hypertension has recently gained new interest.Aldosterone is now suggested to be a more common cause of hypertension than previously believed and has been linked to myocardial fibrosis, independent of its hypertensive effects. Finally, rapid nongenomic aldosterone effects have been proposed to be important in hypertension, in addition to its genomic effects. Forty-eight healthy male volunteers were examined in a randomized, placebo-controlled, double-blind crossover trial to elucidate the rapid nongenomic, vascular effects of aldosterone in humans. Forearm blood flow was measured by venous occlusion plethysmography. First, aldosterone (500 ng/min) and placebo were infused into the brachial artery for 8 minutes. The volunteers then received ascending doses of acetylcholine, N G -monomethyl-L-arginine (L-NMMA), sodium nitroprusside, or phenylephrine. Aldosterone increased forearm blood flow (PϽ0.001, ANOVA). The maximum effect was an increase in forearm blood flow with aldosterone of 7.9Ϯ2.6% compared with 0.1Ϯ1.9% with placebo treatment after 8 minutes. With aldosterone, L-NMMA induced a greater vasoconstriction (PϽ0.05, ANOVA), sodium nitroprusside induced an attenuated vasoconstriction (PϽ0.01, ANOVA), and phenylephrine induced an exaggerated vasoconstriction (PϽ0.01, ANOVA) within minutes as compared with placebo. These data suggest that aldosterone acts through rapid nongenomic effects at the endothelium by increasing NO release and at the vascular smooth muscle cells by promoting vasoconstriction. This is consistent with in vitro data showing an increase in intracellular calcium in both cell types. Disturbances of these aldosterone effects on both levels might be important in promoting hypertension.

The higher mortality rate in patients on hemodialysis is primarily due to the higher rate of cardiovascular disease. Yet, paradoxically, overweight, hypertension, and hyperlipidemia, which are cardiovascular risk factors in the general population, have been reported to correlate with better patient survival in hemodialysis. To examine whether this "risk factor paradox" in hemodialysis is due to the positive influence of accompanying better nutrition, we prospectively obtained data on fasting lipids, biochemical markers of nutrition, body mass index (BMI), and blood pressure (BP) in 453 hemodialysis patients and related them to 1 year mortality. As previously noted, body weight, blood pressure, and certain serum lipids positively correlated with survival. Serum prealbumin, one of the most sensitive and specific biochemical markers for nutrition, correlated positively with hypercholesterolemia (r = 0.30, p < 0.001) and BMI (r = 0.12, p < 0.02), but not with mean arterial pressure (MAP) (r = 0.01, p = NS). By analysis of variance, patients in the upper tertile (i.e., higher levels) of BMI and cholesterol but not MAP had significantly higher serum prealbumin and creatinine compared with those in the lower tertile. Our data lend support to the hypothesis that, in patients on hemodialysis, the positive effect of higher BMI and hyperlipidemia but not of high BP could be partially explained on the basis of the accompanying better nutrition. Although not proven, correcting risk factors while improving nutrition may offer better outcomes for patients on dialysis.