Does Blood Pressure Control by Gentle Ultrafiltration Improve Survival in Hemodialysis Patients?

Agentle ultrafiltration can be achieved using a long and slow hemodialysis. It is easier to achieve gentle ultrafiltration if the interdialytic weight intake is moderate ( i.e., if the patient maintains a low sodium diet) and if diffusion allows for a negative or nil sodium balance during the session ( i.e., dialysate sodium < 140 mmol/L). A gentle ultrafiltration allows control of blood pressure by reducing the extracellular volume to its ideal level, the "dry weight," at the end of the session. Controlling blood pressure reduces cardiovascular mortality, which is by far the foremost cause of death in hemodialysis. Controlling blood pressure means reducing the occurrence of both hypertension and hypotension. Hypotension has been reported to correlate with mortality in hemodialysis as much as or more than hypertension itself. This "U-curve" phenomenon is not paradoxical. It displays two distinct facts on the same figure: an increased early mortality in hypotensive patients (hypotension is a marker of frailty or congestive heart failure, both of which cause increased mortality) and, on the other hand, the well-established, long-term increased mortality in hypertensive patients. Hypotension is not a mandate to undertreat hypertension.