The Impact of A Reduction of Dialysate Calcium on Diastolic Function in Patients on Peritoneal Dialysis: A Prospective Study

Background Cardiovascular disease is the main cause of death in patients on peritoneal dialysis (PD). The standard dialysate calcium content -d[Ca]- of 1.75mmol/L affects calcium balance, promoting calcium overload and impairing ventricular relaxation. Intracellular calcium handling might cause diastolic dysfunction (DD). We tested the hypothesis that reducing d[Ca] in patients on PD would improve DD. Methods d[Ca] was reduced from 1.75 mmol/L to 1.25 mmol/L. Two-dimensional speckle-tracking echocardiography was performed by a well-trained cardiologist at baseline and after 3 months. DD was determined according to the peak E-wave and peak A-wave velocities, wave deceleration time, and the duration of wave A. Diastolic function was normal, DD-1 (impaired ventricular relaxation), and DD-2 (restrictive pattern). Demographic, clinical, and biochemical parameters were evaluated. Results We included 19 patients (age 55 ± 17 years, 57.9% women, 21.1% diabetic, 84.2% on automatic PD). From baseline to 3 months, there was no change in any biochemical parameter. Left ventricular ejection fraction remained stable (from 58.4 ± 7.7 to 56.5 ± 8.1, p=0.192). Diastolic function classified at baseline as normal, DD-1 and DD-2 changed from 21.1%, 52.6% and 26.3–31.6%, 47.4% and 21.1% after 3 months, respectively, p=0.001). Increased filling pressure changed from 21.1–5.3% of patients (p=0.051). Conclusions Low d[Ca] could improve DD in patients on PD. This result might be related to a new set point of calcium myocardium homeostasis in these patients. Whether low d[Ca] may detain the development of heart failure and reduce cardiovascular in this population deserves further investigation.