Effects of Acetate and Bicarbonate Dialysate on Left Ventricular Performance

Whether bicarbonate dialysis (BiHD) improves left ventricular (LV) function more than acetate dialysis (AcHD) and whether AcHD exerts a negative inotropic effect remains controversial. To address this question, the LV contractile responses to both dialysate buffers were tested in six stable chronic dialysis patients not taking any cardiac or antihypertensive medicines. The patients were studied with echocardiography before and after an isovolemlc dialysis (no weight change) with either buffer, and neither heart rate nor blood pressure were significantly altered during either procedure. The patients were studied at three different filling volumes so that LV function curves could be constructed. Both dialysates were associated with comparable and significant changes in LV end systolic volume (AcHD, 55 ± 5 to 49 ± 5 mL, P < .001; BiHD, 56 ± 5 to 49.5 ± 5 mL, P < .001), stroke volume (AcHD, 88 ± 7 to 97 ± 5 mL, P < .01; BiHD, 89 ± 7 to 97 ± 7 mL, P < .05), and LV ejection fraction (AcHD, 60 ± 7% to 65 ± 8%, P < .05; BIHD, 60 ± 3 t067 ± 2%, P < .001). In addition, the mean velocity of circumferential fiber shortening (VCF), an index of ventricular contractility, also increased significantly after dialysis with both dialysates (AcHD, .96 ± .08 to 1.20 ± .15, P < .001; BiHD, .93 ± .09 to 1.29 ± .11, P < .001). Finally, both dialysates were associated with upward shifts in the LV function curve of a similar magnitude. In summary, these results in stable dialysis patients show comparable improvements in LV performance with AcHD and BiHD over a range of preloads. Acetate does not appear to exert negative inotropic effects during routine dialysis.