Dialysate Sodium Levels, Ambulatory Aortic Blood Pressure and Arterial Stiffness in Hemodialysis Patients.

Background: Increased aortic blood-pressure(BP) and arterial stiffness are associated with higher cardiovascular risk in hemodialysis. Previous works showed that lower dialysate sodium is associated with lower brachial-BP; data on aortic-BP and arterial stiffness are limited. This study aimed to investigate the effects of different dialysate sodium concentrations on 72-h aortic-BP and arterial stiffness parameters in hemodialysis patients.

Methods: This analysis is part of a prospective, non-randomized interventional study. Twenty-five hemodialysis patients underwent a set of three periods of different dialysate sodium concentrations; six sessions with dialysate sodium of 137meq/L, followed consecutively by six sessions with 139meq/L and, finally, six sessions with 141meq/L. At the start of the sixth hemodialysis session on each sodium concentration, 72-h ABPM (Mobil-O-Graph) was performed to evaluate aortic-BP and arterial stiffness indices during the overall 72-h, different 24-h, day-time and night-time periods.

Results: Mean 72-h aortic SBP/DBP were higher with increasing dialysate sodium concentrations (137meq/L: 114.2±15.3/77.0±11.8mmHg vs 139meq/L: 115.4±17.3/77.9±14.0mmHg vs 141meq/L: 120.5±18.4/80.5±14.7mmHg, p=0.002/p=0.057, respectively). Wave-reflections parameters (AIx, AIx(75), AP) were not significantly different between the three dialysate sodium concentrations. Ambulatory PWV was significantly higher with increasing dialysate sodium concentrations (137meq/L: 8.5±1.7m/s vs 139meq/L: 8.6±1.6m/s vs 141meq/L: 8.8±1.6m/s, p<0.001). In generalized linear-mixed-models including 72-h brachial SBP as random covariate, the adjusted marginal-means of 72-h PWV were not significantly different between-groups.

Conclusions: This study showed that lower dialysate sodium concentrations are associated with significant decreases in ambulatory aortic BP and PWV. This study showed that higher dialysate sodium concentrations are associated with significant increases in ambulatory aortic BP and PWV. These findings further support the need for modification of dialysate sodium concentration in hemodialysis.