P0226CONSEQUENCES OF SUPRAPHYSIOLOGICAL DYALYSATE MAGNESIUM CONCENTRATION ON ARTERIAL STIFFNESS, HEMODYNAMIC PROFILE AND ENDOTHELIAL FUNCTION IN HEMODIALYSIS: A RANDOMIZED CROSS-OVER STUDY AND FOLLOW-UP

Abstract Background and Aims Increasing dialysate magnesium improves vascular stiffness in subjects undergoing maintenance hemodialysis. The present findings merit a larger trial to evaluate the effects of a 0.75 mmol/L D-Mg2+ on major clinical outcomes. Method A randomized 4-week cross-over study aimed at investigating the consequences of increasing D-Mg2+ from 0.50 to 0.75 mmol/L on arterial stiffness, hemodynamic profile, and endothelial function in subjects undergoing hemodialysis. The long-term effect of higher D-Mg2+ on mineral metabolism markers was investigated in a six-month follow-up. Data were analysed by linear mixed models for repeated measures. Results Pulse wave velocity and pulse pressure significantly decreased on the higher D-Mg2+ compared with the standard one by -0.91 m/sec (95% confidence interval: -1.52 to -0.29; p=0.01) and -9.61 mmHg (-18.89 to -0.33, p=0.04), respectively. A significant reduction in systolic blood pressure of -12.96 mmHg (-24.71 to -1.22, p=0.03) was also observed. No period or carryover effects were observed. During the long-term follow-up the higher D-Mg2+ significantly increased total serum and ionized Mg (mean percentage change from baseline to follow-up +21%; and + 27%; p≤0.001 for both), while parathormone (PTH) decreased significantly (-11%, p=0.03). Conclusion Increasing dialysate magnesium improves vascular stiffness in subjects undergoing maintenance hemodialysis. The present findings merit a larger trial to evaluate the effects of a 0.75 mmol/L D-Mg2+ on major clinical outcomes.