Effects of acetate and bicarbonate hemodialysis on cardiac function in chronic dialysis patients

Previous studies have suggested that acetate hemodialysis causes myocardial depression. This study examines the acute effects of hemodialysis using, alternately, bicarbonate and acetate in the dialysate, on cardiac function in ten patients. These patients were also studied during acetate dialysis using a large surface area (SA) dialyzer. Each patient was dialyzed for 4 hr with: (1) 1.0 m² SA dialyzer and bicarbonate dialyslate; (2) 1.0 m² SA dialyzer and acetate bath, and; (3) 2.5 m² SA dialyzer and acetate dialysate. All studies were performed during isovolemic dialysis to separate the effects of changes in cardiac filling volume with hemodialysis, from changes in myocardial contractility. Myocardial function, as assessed by pre- and postdialysis echocardiography derived fractional shortening (Fs) and mean velocity of circumferential shortening (VCF), improved (P < 0.05) to the same extent, after all three dialysis treatments. This occurred despite greater increases (P < 0.002) in pH and bicarbonate after bicarbonate dialysis and decreases (P < 0.05) in PO₂, PCO₂ and bicarbonate after acetate dialysis with 2.5 m² SA dialyzer. These results indicate that diffusive dialysis with both acetate and bicarbonate dialysate improved myocardial function and do not support the view that acetate influx during dialysis can lead to myocardial depression.