Hemodialysis with high-calcium dialysate impairs cardiac relaxation

Background. During hemodialysis (HD), serum ionized calcium is directly rel ated to the dialysate calcium concentration. We have recently shown an acut e induction of hypercalcemia to impair left ventricular (LV) relaxation. In the current study we sought to establish whether changes in serum Ca++ als o affect LV function during HD. Methods. We echocardiographically examined the LV relaxation and systolic f unction of 12 patients with end-stage renal disease before and after three HD treatments with dialysate Ca++ concentrations of 1.25 mmol/liter (dCa(+)1.25), 1.5 mmol/ liter (dCa(++)1.50), and 1.75 mmol/liter (dCa(++)1.75), r espec tively. Age- and sex-matched healthy controls were also examined echo cardiographically. Results. The LV posterior wall thickness and the interventricular septum th ickness, and the LV end-diastolic dimension and the end-systolic dimensions were significantly greater in the patients when compared with the controls , and the LV fractional shortening, the ratio of peak early to peak late di astolic velocities (E/A(max)), and the isovolumic relaxation time (IVRT) sh owed impairment of LV relaxation and systolic function in the patients. Ser um ionized calcium increased significantly during the dCa(++) 1.5 HD (1.24 +/- 0.10 vs. 1.34 +/- 0.06 mmol/liter, P = 0.004) and dCa(++)1.75 KD (1.19 +/- 0.10 vs. 1.47 +/- 0.06 mmol/liter, P = 0.002), and plasma intact parath yroid hormone decreased significantly during the dCa(++) 1.75 HD (medians 8 .2 vs. 2.7 pmol/liter, P = 0.002). LV systolic function was not altered dur ing any of the treatments. The changes in E/A(max) and IVRT suggested impai rment of relaxation during all sessions, but only during the dCa(++) 1.75 H D was the impairment statistically significant (E/A(max) 1.153 +/- 0.437 vs . 0.943 +/- 0.352, P < 0.05; IVRT 147 +/- 29 vs. 175 +/- 50 msecond, P < 0. 05). Conclusion. HD with high-calcium (dCa(++) 1.75 mmol/liter) dialysate impair s LV relaxation when compared with lower calcium dialysate (dCa(++)1.25 and dCa(++)1.5 mmol/liter) treatments.