Hypervolemia and Blood Pressure

Abstract

Volume expansion is one of the most important factors that results in higher levels of blood pressure in patients with chronic kidney disease. This has been known for many years, and led to the original description of the concept of dry weight in 1967.1 This is especially important in patients with end-stage renal disease who require dialysis for volume control. Inadequate control of volume or inability to establish and maintain an appropriate dry weight for a dialysis patient may be an important factor in contributing to excess mortality. In this issue of Hypertension , Agarwal2 has importantly demonstrated the value of relative plasma volume slope monitoring in predicting overall mortality among >300 patients on long-term hemodialysis. A simple cross-sectional analysis of relative plasma volume slope during dialysis was predictive of mortality independent of conventional and unconventional cardiovascular risk factors, independent of ultrafiltration volume, ultrafiltration rate, ultrafiltration volume per kilogram, ultrafiltration rate index per postdialysis weight, and interdialytic ambulatory blood pressure. Why is the relative plasma volume slope such a powerful predictor for mortality? Is it simply that steeper slopes of relative plasma volume monitoring are associated with greater likelihood of the attainment of a more euvolemic state and, thus, may put less stretch and strain on the myocardium? Probing for dry weight in clinical practice can be complicated.3 It is an inexact clinical science. The clinical examination is not always helpful to assess volume. Changes in body mass because of alterations in nutrition and dietary electrolyte and volume consumptions may complicate the process of dry weight assessment and achievement. Inadequate achievement of dry weight results in …