Preservation of Residual Renal Function in Dialysis Patients: Effects of Dialysis-Technique–Related Factors

Abstract

Objectives Residual renal function (RRF) is of paramount importance to dialysis adequacy, morbidity, and mortality, particularly for long-term continuous ambulatory peritoneal dialysis (CAPD) patients. Residual renal function seems to be better preserved in patients on CAPD than in hemodialysis (HD) patients. We analyzed RRF in 45 patients with end-stage renal disease (ESRD), commencing either CAPD or HD, to prospectively define the time course of the decline in RRF, and to evaluate dialysis-technique–related factors such as cardiovascular stability and bioincompatibility. Study Design Single-center prospective investigation in parallel design with matched pairs. Materials Fifteen patients starting CAPD and 15 matched pairs of patients commencing HD were matched according to cause of renal failure and RRF. Hemodialysis patients were assigned to two dialyzer membranes differing markedly in their potential to activate complement and cells (bioincompatibility). Fifteen patients were treated exclusively with the cuprophane membrane (bioincompatible) and the other 15 patients received HD with the high-flux polysulfone membrane (biocompatible). Measurements Residual renal function was determined at initiation of dialytic therapy and after 6, 12, and 24 months. Dry weight (by chest x ray and diameter of the vena cava) was closely recorded throughout the study, and the number of hypotensive episodes counted. Results Residual renal function declined in both CAPD and HD patients, although this decline was faster in HD patients (2.8 mL/minute after 6 months and 3.7 mL/min after 12 months) than in CAPD patients (0.6 mL/min and 1.4 mL/ min after 6 and 12 months respectively). It declined faster in patients with bioincompatible than with biocompatible HD membranes (3.6 mL/min vs 1.9 mL/min after 6 months). Eleven percent of the HD sessions were complicated by clinically relevant blood pressure reductions, but there were no differences between the two dialyzer membrane groups. None of the CAPD patients had documented hypotensive episodes. None of the study patients suffered severe illness or received nephrotoxic antibiotics or radiocontrast media. Conclusions The better preservation of RRF in stable CAPD patients corresponded with greater cardiovascular stability compared to HD patients, independently of the membrane used. Furthermore, there was a significantly higher preservation of RRF in HD patients on polysulfone versus cuprophane membranes, indicating an additional effect of biocompatibility, such as less generation of nephrotoxic substances by the membrane. Thus, starting ESRD patients on HD prior to elective CAPD should be avoided for better preservation of RRF.

Dialysis modality and survival: Done to death

“…better preservation of RKF with PD compared to HD. 75,76 Furthermore, the increasing use of frequent HD modalities, may accelerate loss of RKF. The Frequent Hemodialysis Network Nocturnal Trial that randomized patients to frequent 6X/week (nocturnal) or thrice-weekly in-center HD, frequent nocturnal HD was associated with a more rapid loss of RKF.…”

Is it time to revisit residual renal function in haemodialysis? (Review Article)

“…43 Their results were subsequently duplicated by various authors (Table 1). [44][45][46][47][48][49] These studies all reported a significantly higher rate of decline of RRF in HD compared with PD patients. This was postulated to be due to improved cardiovascular stability with decreased hypotensive episodes in PD patients as a result of the continuous nature of the dialysis therapy, and/or the fact that the peritoneal membrane is more biocompatible than the membranes used in haemodialysers.…”

“…Most, but not all recent studies ( Table 2) have reported that the use of biocompatible membranes such as polysulphone is associated with a slower rate of decline of RRF when compared with traditional bioincompatible cellulose membranes. 40,46,48,49,[53][54][55][56] The inflammatory milieu generated by the use of bioincompatible cellulose membranes is generally thought to be associated with a more rapid decline in RRF. 57,58 One limitation of these studies is the possible confounding factor of flux characteristics as the biocompatible synthetic membranes were largely high flux, while the bioincompatible membranes were low flux in nature.…”

Residual renal function and dialysis modality: Is it really beneficial to preserve residual renal function in dialysis patients? (Review Article)

“…[37][38][39][40] Dialysis-related factors should be clearly identified and separated from the previous ones. 41 Few studies have attempted to identify precisely the role of the dialysis modality by itself. PD and HD and their related technical variants are the two main renal replacement options.…”