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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.

Introduction: Patients on peritoneal dialysis (PD) are usually exposed to a high dialysate calcium concentration (D[Ca]), which is associated with undesirable effects. Low D[Ca] might overstimulate parathyroid hormone (PTH), as shown by previous studies carried out before the incorporation of calcimimetics in clinical practice. We hypothesized that a reduction in D[Ca] is safe and without risk for a rise in serum PTH. Methods in this prospective study, the D[Ca] was reduced from 1.75 mmol/L to 1.25 mmol/L for one year in prevalent patients on PD. Demographic, clinical, and biochemical parameters were evaluated at baseline, 3, 6, and 12 months of follow-up. Results Patients (N = 20) aged 56 ± 16 years, 50% male, 25% diabetic. There was no significant change in calcium, phosphate, alkaline phosphatase, 25(OH)-vitamin D or PTH over time. Medication adjustments included an increase in calcitriol and sevelamer. After 1 year, absolute and percentual change in PTH levels were 36 (-58, 139) pg/ml, and 20% (-28, 45) respectively. The proportion of patients with PTH > 300 pg/ml did not change during the follow-up (p = 0.173). Conclusion Low D[Ca] concentration should be considered to patients on PD as a valuable and safe option. Medication adjustments to detain PTH rising, however, are advised.

Piraciaba MCT. The impact of a reduction of dialysate calcium on the myocardium and on markers of mineral and bone disease [thesis].