The Effect of Low Dialysate Sodium Concentration on Ambulatory Aortic Blood Pressure and Arterial Stiffness in Patients With Intradialytic Hypertension: A Randomized Crossover Study.

Background: Intradialytic hypertension (IDH) is associated with increased cardiovascular risk. Arterial stiffness is a strong predictor of adverse outcomes in dialysis patients and may contribute to the development of the phenomenon, as patients with IDH exhibit higher ambulatory aortic blood pressure (BP) and arterial stiffness parameters than patients without IDH. 

Methods: This analysis examined the effect of low (137mEq/L) compared to standard (140mEq/L) dialysate sodium concentration on 48-hour aortic BP and arterial stiffness parameters in IDH patients. In this prespecified secondary analysis of a randomized, single-blind, crossover study, 29 IDH patients underwent four hemodialysis sessions with low followed by four sessions with standard dialysate sodium or vice-versa. Mean 48-hour, pre-/post-dialysis and intradialytic aortic systolic/diastolic BP (SBP/DBP), and arterial stiffness indices were assessed.

Results: Mean 48-hour aortic SBP/DBP were significantly lower with low versus standard dialysate sodium (124.1±16.4/83.0±14.1mmHg vs 128.5±12.9/85.8±14.1mmHg, p=0.013/p=0.006 respectively). Low dialysate sodium also significantly reduced pre-dialysis aortic SBP (126.4±17.4 vs 135.6±18.6mmHg, p=0.044) and post-dialysis aortic SBP (137.0±20.0 vs 147.9±18.1mmHg, p=0.01). All wave reflection indices were numerically lower with low dialysate sodium; among them, heart rate-adjusted augmentation index (AIx(75)) was significantly lower during the 48-hour (26.3±6.7 vs 27.7±5.8%, p=0.03), 44-hour, day-time and intradialytic periods. Low dialysate sodium resulted in decreased 48-hour pulse wave velocity (PWV) (9.9±2.5 vs 10.1±2.6m/s, p=0.008); similar differences for PWV were observed during all examined time intervals.

Conclusions: In conclusion, ambulatory 48-hour aortic BP and arterial stiffness parameters were significantly lower using low compared to standard dialysate sodium in IDH patients. These findings further support the use of low dialysate sodium for BP management in this population.