Comparison of cellulose diacetate and polysulfone membranes in the outcome of acute renal failure. A prospective randomized study. Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters. The Italian Cooperative Dialysis Study Group. Biocompatibility and performance of a modified cellulosic and a synthetic high flux dialyzer. A randomized crossover comparison between cellulose triacetate and polysulphon. Tolerance of hemodialysis: a randomized prospective trial of high-flux versus conventional high-efficiency hemodialysis. Patient survival and renal recovery in acute renal failure: randomized comparison of cellulose acetate and polysulfone membrane dialyzers. Biocompatible membranes preserve residual renal function in patients undergoing regular hemodialysis. Preservation of residual renal function in dialysis patients: effects of dialysis-technique-related factors. Biocompatible membranes in acute renal failure: prospective case-controlled study. A multicenter comparison of dialysis membranes in the treatment of acute renal failure requiring dialysis.
Whether the nature of haemodialysis (HD) membranes can influence the outcome of acute renal failure (ARF) remains debatable. Recent studies have suggested that dialysis with bioincompatible unsubstituted cellulosic membranes is associated with a less favourable patient outcome than dialysis with biocompatible synthetic membranes. Since we generally use a modified cellulosic membrane with substantially lower complement- and leukocyte-activating potential than cuprophane, for dialysis of patients with ARF, and because there are no data in the literature regarding the influence of modified cellulosic membranes on the outcome of patients with ARF, we compared the outcome of ARF patients dialysed either with cellulose diacetate or with a synthetic polysulfone membrane. We also investigated the potential role of permeability by comparing membranes with high-flux versus low-flux characteristics.
                This prospective, randomized, single centre study included 159 patients with ARF requiring HD. Patients were stratified according to age, gender, and APACHE II score and then randomized in chronological order to one of three dialysis membranes: low-flux polysulfone, high-flux polysulfone and meltspun cellulose diacetate.
                Aetiologies of ARF and the prevalence of oliguria were similarly distributed among the three groups. There was no significant difference between the three groups for survival (multivariate Cox's proportional hazards model, P=0.57), time necessary to recover renal function (P=0.82), and number of dialysis sessions required before recovery (P=0.86). Multivariate analysis showed that survival was significantly influenced only by the severity of the disease state (APACHE III score, P<0.0001), but not by the nature of the dialysis membrane (P=0.57) or the presence of oliguria (P=0.24).
                Among patients with ARF requiring HD survival and recovery time are not significantly influenced by the use of either meltspun cellulose diacetate or the more biocompatible high-flux or low-flux polysulfone. Dialysis using modified cellulose membranes is just as effective as dialysis using synthetic polysulfone membranes, but at a lower cost. In addition, the flux of the membrane did not influence patient outcome. There is increasing evidence that the biochemical and cellular phenomena induced by blood/ membrane/dialysate interactions contribute to dialysis-related intradialytic and long-term complications. However, there is a lack of large, prospective, randomized trials comparing biocompatible and bioincompatible membranes, and convective and diffusive treatment modalities. The primary aim of this prospective, randomized trial was to evaluate whether the use of polysulfone membrane with bicarbonate dialysate offers any advantage (in terms of treatment tolerance, nutritional parameters and pre-treatment beta-microglobulin levels) over a traditional membrane (Cuprophan). A secondary aim was to assess whether the use of more sophisticated methods consisting of a biocompatible synthetic membrane with different hydraulic permeability at different ultrafiltration rate (high-flux hemodialysis and hemodiafiltration) offers any further advantages. Seventy-one Centers were involved and stratified according to the availability of only the first two or all four of the following techniques: Cuprophan hemodialysis (Cu-HD), low-flux polysulfone hemodialysis (LfPS-HD), high-flux polysulfone high-flux hemodialysis (HfPS-HD), and high-flux polysulfone hemodiafiltration (HfPS-HDF). The 380 eligible patients were randomized to one of the two or four treatments (132 to Cu-HD, 147 to LfPS-HD, 51 to HfPS-HD and 50 to HfPS-HDF). The follow-up was 24 months. No statistical difference was observed in the algebraic sum of the end points between bicarbonate dialysis with Cuprophan or with low-flux polysulfone, or among the four dialysis methods under evaluation. There was a significant decrease in pre-dialysis plasma beta 2-microglobulin levels in high-flux dialysis of 9.04 +/- 10.46 mg/liter (23%) and in hemodiafiltration of 6.35 +/- 12.28 mg/liter (16%), both using high-flux polysulfone membrane in comparison with Cuprophan and low-flux polysulfone membranes (P = 0.032). The significant decrease in pre-dialysis plasma beta 2-microglobulin levels could have a clinical impact when one considers that beta 2-microglobulin accumulation and amyloidosis are important long-term dialysis-related complications. The biocompatibility and performance of two high flux membranes (modified cellulosic: cellulose-triacetate (CTA), and a synthetic material: polysulphon [PS]) were assessed in 31 stable patients on hemodialysis (HD) in a randomized crossover study. Parameters evaluated included leukocytes, complement activation products C3a and C5a, cytokines, lymphocyte subpopulations, urea, creatinine, phosphate, and beta 2 microglobulin. Considering biocompatibility, the drop in the number of leukocytes was more pronounced during CTA HD compared with PS (p = 0.045), although both were low in comparison with cuprammonium dialysis in the same patients, as observed during a separate study. Both membranes induced a low and transient state of complement activation. Interleukin 1 beta and interleukin 6 could not be detected at all, whereas tumor necrosis factor alpha levels were marginally elevated before and after HD with both membranes. During the first 30 min of HD with either membrane, the numbers of CD8+ cells decreased significantly, resulting in an increase in the CD4/CD8 ratios; in addition, the number of NK cells decreased. Performance, as measured by extraction ratios for small molecular weight solutes and Kt/V urea, was significantly better during CTA dialysis (p < 0.001), but almost similar after correction for membrane surface area. On the basis of these data, it seems justified to conclude that, whereas biocompatibility of the PS dialyzer appeared slightly superior to CTA, performance of both dialyzers was comparable. Hemodialysis is frequently complicated by hypotension and associated symptoms. It has been suggested that these symptoms may be related to the biochemical changes caused by cellulosic dialysis membranes. In this study, a prospective randomized crossover trial was conducted comparing the incidence of hypotension and acute symptoms during dialysis with large-surface-area (1.6 m2) cellulosic (cuprophane [CUP]) and noncellulosic (polyacrylonitrile [PAN], AN69) membranes. Dialyzers were used for a single use only. There was no difference in predialysis BUN, predialysis blood pressure, intradialytic weight gain, blood flow, dialysis efficiency (urea reduction), dialysis duration, hematocrit, or erythropoietin dose between the two study phases. When these clinical characteristics were matched, there was no difference in the number of episodes of hypotension (CUP, 19 +/- 3; PAN, 22 +/- 3; P = not significant [NS]). The incidence of symptomatic hypotension, as reflected by the number of episodes of hypotension requiring more than 100 mL of saline for correction, was also not different between study phases (CUP, 10 +/- 1; AN69, 11 +/- 2; P = NS). The incidence of intradialytic symptoms, including emesis, cramping, headache, angina, pruritus, and bronchospasm, was similar during the two study phases (CUP, 11 +/- 2; AN69, 10 +/- 1; P = NS). It was concluded that noncellulosic membranes do not offer any significant advantage over cellulosic membranes in reducing the acute complications of hemodialysis. To investigate survival and renal recovery after dialysis in patients with acute renal failure with use of synthetic membranes compared with substituted cellulose membranes.
                We prospectively studied survival and recovery of renal function of 66 patients with acute renal failure who required intermittent hemodialysis. Patients were randomized to exclusive treatment with either cellulose acetate (CA) or polysulfone (PS) hemodialysis membranes. Additionally, markers of biocompatibility (complement, leukocyte counts, cytokine concentration) were measured at initiation and 1 hour after initiation of dialysis among 10 patients equally distributed between the CA and PS groups.
                The cohorts were indistinguishable with respect to age, sex, presence of diabetes mellitus, Acute Physiology and Chronic Health Evaluation II scores, percentage in the intensive care unit (ICU), and adequacy of dialysis. Survival (76% CA, 73% PS; P=.78) and recovery of renal function at 30 days (58% CA, 39% PS; P=.14) were not statistically different in the 2 groups. Among 26 CA patients and 27 PS patients treated in the ICU, survival was not statistically different (73% CA, 67% PS; P=.61); however, the proportion of patients recovering renal function suggested a benefit favoring CA membranes (65% CA, 37% PS; P=.04). Additionally, markers of biocompatibility were not significantly different between groups among the 10 patients equally distributed between the CA and PS groups.
                Overall clinical outcomes among patients with acute renal failure treated with CA hemodialysis membranes and those treated with PS membranes were not significantly different. The observed advantage favoring renal recovery among this ICU population treated with CA hemodialysis membranes warrants further investigation. Initiation of hemodialysis causes a further decrease of residual renal function (RRF). To assess the impact of the biocompatibility of the dialysis membrane, we performed a prospective randomized investigation in 20 normotensive patients with tubulointerstitial nephritis. The patients were randomly allocated to treatment with either a high-flux polysulfone or cellulose membrane over a period of 12 months. RRF, defined by creatinine clearance and daily urine volume, was found to decrease in both groups of patients after the initiation of hemodialysis. Of the two membranes used, however, the cellulose membrane caused an accelerated decrease of RRF (P < 0.05). The better maintenance of RRF in patients treated with polysulfone membranes was associated with higher Kt/V values and increased hematocrit values (P < 0.05). The pathophysiologic mechanism underlying the more rapid decline of RRF could not be explained by intradialytic hypotension, but may be related to the nephrotoxic effects of inflammatory mediators due to bioincompatibility. Therefore, the use of polysulfone membranes might be preferable in patients with relevant RRF. 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.
                Single-center prospective investigation in parallel design with matched pairs.
                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).
                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.
                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.
                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. The mortality of critically ill patients with acute renal failure has been halved through intervention by haemodialysis. However, several reports suggest that the course of the disorder may be prolonged by this procedure. Our prospective randomised study was done to see whether the generation of inflammatory mediators by bio-compatible membranes has an adverse effect on the outcome of acute renal failure. 52 patients, similar in age, severity of acute renal failure, general disease status (APACHE II), and management of acute renal failure or its related conditions, were divided into two groups. Haemodialysis was done with cuprophane or polyacrylonitrile membranes. Cuprophane membranes induced intense activation of the complement system (as judged by measurement of C3a) and lipooxygenase pathway (leukotriene B4) resulting in alterations of neutrophil kinetics and function. The cuprophane group had a lower survival rate (38 vs 65%), a higher proportion of patients dying from sepsis (71 vs 40%), required more haemodialysis sessions (12 vs 9), and demonstrated delayed resolution and recovery from acute renal failure than the polyacrylonitrile group. The difference in mortality regarding lethal sepsis as cause of death was statistically significant. Our observations indicate that the outcome of critically ill patients with acute renal failure may be influenced by bio-incompatibility reactions to the dialysis membrane. These results have direct implications for such patients on haemodialysis. The mortality of patients with acute renal failure (ARF) remains high, and in several large studies approaches 60%. This mortality is particularly high in patients with ARF who require dialysis and has not changed substantially over several years, despite the introduction of major advances in monitoring and treatment. Increasing prevalence of comorbidities has been suggested as the major factor in this persistently high mortality. This study investigates the potential role of the dialysis membrane on patient outcome in a prospective multicenter study of 153 patients with ARF requiring dialysis. The membrane assignment was made in alternating order and was limited to membranes with low complement activation (Biocompatible [BCM]) and cellulosic, high complement activation (Bioincompatible [BICM]). Both types of membranes were low-flux membranes. Patients were dialyzed with the assigned membrane until recovery, discharge from hospital, or death. The severity of illness of each patient was assessed using the APACHE II score at the time of initiation of dialysis. A logistic regression analysis was used to adjust for the APACHE II score. The results of the study showed a statistically significant difference in survival (57% in patients on BCM, 46% in patients on BICM; P = 0.03) and in recovery of renal function (64% in patients on BICM and 43% in patients on BICM; P = 0.001). These differences were particularly marked in the patients who were nonoliguric (>400 ml/d of urine output) at initiation of the study. In the subset of patients who were nonoliguric at the start of dialysis, a larger fraction (70%) became oliguric after initiating dialysis on a BICM membrane, in contrast to 44% who were initiated on a BCM membrane (P = 0.03). It is concluded that the biocompatibility of the dialysis membrane plays a role in the outcome of patients with ARF, particularly those who are nonoliguric at the time of initiation of dialysis.
We found no evidence of benefit when synthetic membranes were compared with cellulose/modified cellulose membranes in terms of reduced mortality no reduction in dialysis-related adverse symptoms. Despite the relatively large number of RCTs undertaken in this area none of the included studies reported any measures of quality of life.