The Cardiorenal Protective Effects of Low-dose Tolvaptan in Peritoneal Dialysis Patients with Volume Overload

INTRODUCTION: To compare the efficacy and safety of tolvaptan versus conventional therapy in peritoneal dialysis (PD) patients with volume overload, and to evaluate its impact on cardiac and renal function to support comprehensive clinical management. METHODS: Sixty patients with PD who underwent regular follow-up at the Second Hospital of Jilin University between May 1, 2023, and December 31, 2025, were prospectively enrolled and randomly allocated to a tolvaptan group or a control group, with 30 patients in each group. The control group received conventional pharmacological therapy, whereas the tolvaptan group received oral tolvaptan (15 mg) every other day in combination with conventional therapy for 6 months. Clinical parameters and adverse events were recorded at baseline, at 3 and 6 months after treatment initiation, and at 3 months after treatment discontinuation (9 months after treatment initiation) to assess the efficacy and safety of tolvaptan for the management of volume overload in PD patients. RESULTS: A total of 56 patients completed the follow-up, with 28 patients in each group. During the study period, overhydration (OH) decreased continuously in both groups, with a greater reduction in the tolvaptan group (linear trend test, p = 0.033). Urine volume in the tolvaptan group increased significantly in the first week (p = 0.02), then gradually decreased, but remained higher than that in the control group at all time points (p < 0.05). Peritoneal ultrafiltration in the tolvaptan group showed an initial decrease, followed by an increase. Compared with baseline, the residual renal glomerular filtration rate (GFR) in the tolvaptan group remained stable at 3 and 6 months (p = 0.695, p = 0.178), but decreased significantly after discontinuation (p < 0.001), whereas in the control group, residual renal GFR was significantly lower than baseline at all time points (p < 0.05). Lg(BNP) levels declined in both groups , with no significant difference in trends (p = 0.656). The left ventricular ejection fraction (LVEF) in the tolvaptan group increased during the first 6 months (p =0.019) but decreased at 9 months, whereas no significant change occurred in the control group. Lg(LVMI) decreased in the tolvaptan group but increased in the control group, with a significant difference in trends (p < 0.001). One patient in the tolvaptan group developed hypernatremia, which improved after symptomatic treatment, with no other adverse events occurred. CONCLUSION: With strict monitoring of blood sodium, low-dose tolvaptan safely and effectively improved the volume status in PD patients with volume overload, delayed the decline of residual renal function, and may protect cardiac function.