Hemodiafiltration Group Research Articles

Does hemodiafiltration improve the removal of homocysteine?

High prevalence of hyperhomocysteinemia is common in hemodialysis (HD) patients and could contribute to worsen the cardiovascular risk. Beyond vitamin B status, dialysis modality itself could influence homocysteine (Hcy) levels. The objective was compare the reduction rate (RR) of Hcy and cysteine in stable dialyzed patients treated by standard HD or hemodiafiltration (HDF). Seventy-five patients undergoing stable dialysis through standard high-flux HD (n = 35) or HDF (n = 40) were included. Biological parameters were determined before and after a midweek dialysis session. Urea percent reduction per session and Kt/V index (K, body urea clearance, T, time of dialysis, and V, urea distribution volume), defined as a marker of dialysis efficacy, were similar between HD and HDF groups. By contrast, higher RR of beta2 microglobulin (β2m) was observed in HDF compared with HD (78.6 vs. 72.0%, respectively; P < 0.001). Likewise, higher RR of Hcy was obtained with HDF compared to HD (46.0 vs. 41.5%, respectively; P < 0.05), whereas the RR of cysteine was similar in both groups. Interestingly, a positive correlation between Hcy RR and urea Kt/V index was observed (r = 0.29, P < 0.05) and between Hcy RR and β2m RR (r = 0.45, P < 0.001). Time-averaged concentration (TAC) of Hcy was lower with HDF compared with HD (17.8 vs. 19.1 μmol/L, respectively), although not significant. There was no difference in median Hcy according to dialysis modality for neither pre- nor postdialysis levels. Significant higher removal of Hcy was observed with HDF compared with standard HD, although urea Kt/V index was similar. Enhanced removal of middle molecules, such as β2m, could be involved in Hcy RR improvement with HDF.

Haemodiafiltration Does Not Reduce the Frequency of Intradialytic Hypotensive Episodes when Compared to Cooled High-Flux Haemodialysis

Introduction: Intradialytic hypotension remains the commonest complication of outpatient haemodialysis (HD) treatments. On-line haemodiafiltration (HDF) has been reported to reduce the frequency of intradialytic hypotension. We introduced on-line HDF into our satellite dialysis program, and prospectively audited the effect of HDF on cardiovascular stability. Methods: 34 patients’ dialysis schedules (Tuesday/Thursday/Saturday) were converted to online post-dilutional HDF, and 44 patients’ dialysis schedules (Monday/Wednesday/Friday) remained on high-flux HD. Blood pressure and intra-treatment complications were monitored prospectively for 12 months. Results: There was no significant change in pre-treatment mean arterial blood pressure in the HDF group during the 12 months of the study (pre-treatment 113.7 ± 0.7 mm Hg vs. 109.3 ± 2.8 after 12 months), or for the HD cohort (113.9 ± 2.7 vs. 117.9 ± 2.6). However, the frequency of intradialytic hypotensive episodes was greater for the HDF cohort: 25.9 versus 16.5% in the HD cohort, p = 0.0116. During HDF, on average >16 litres of substitution fluid was used and the median temperature was 36°C (35°C–36°C), higher than the dialysate in the HD cohort which was 35°C (35°C–36°C), p < 0.05. Conclusion: In this study, HDF did not improve blood pressure control or reduce the frequency of intradialytic hypotensive episodes compared to high-flux HD using cooled dialysate.

Clinical study on effects of different blood purification treatment to cardiovascular stability

Objective To compare different blood purification techniques on cardiovascular stability in patients with chronic renal failure (CRF) and its inherent possible mechanism. Methods 90patients with CRF were randomly divided into 3 groups. Group A (HD Group) was applied 3 times per week hemodialysis (HD) treatment; Group B (HDF group) 2 times a week routine standard hemodialysis (HD)treatment and 1 time a week hemodiafiltration (HDF) treatment; Group C (HP group) 2 times a week routine standard blood dialysis (HD) treatment and 1 time a week hemoperfusion (HP) combined with hemodialysis (HD) treatment. The treatment time in every group is 10 weeks, after that there was an interval of 2 weeks with a Fresenius F6 or F8 routine HD treatment , the total time was 6 months. The incidence of cardiovascular complications in the three groups during dialysis, and parathyroid hormone (iPTH), plasma renin (RA),angiotensin Ⅱ (Ang Ⅱ ) changes after 6 months of treatment were compared. Results During dialysis,patients of groups B and C compared with group A significantly reduced cardiovascular complications( group B is 11.3%, group C is 10.9%, but group A is 20.4% ), after treatment plasma iPTH, renin (RA),angiotensin Ⅱ (Ang Ⅱ ) were also decreased significantly compared with group A, but the groups B and C had no significant difference. Conclusion Patients with Hemodialysis or hemoperfusion treatment have better cardiovascular stability, This may be associated with the effective removal of plasma RA, Ang Ⅱ , parathyroid hormone (iPTH) and other middle molecule toxins, both treatments have an equal effect due to simple operation and low equipment requirements, hemoperfusion is much easier to be carried out universally. Key words: Cardiovascular complications; Hemodiafiltration HDF; Hemoperfusion; Parathyroid hormone; Renin; Angiotensin Ⅱ (Ang Ⅱ )

Clinical study on hemodialysis patients with high PTH

Objective To investigate the effect of two different blood purification methods on serum parathyroid hormone(PTH) in chronic hemodialysis patients. Methods 101 patients were randomly divided into two groups:hemodialysis + hemoperfusion group( HD + HP group) and hemodiafiltration group( HDF group). Patients in HD + HP group were treated with resin absorptive devices combined hemodialysis, patients in HDF group treated with hemodiafiltration. Routine determination of serum phosphorus and radioimmunoassay of PTH level were carried out before and after treatment. Results HDF group and HP + HD group were effective for the removal of serum phosphorus,and the clearance rate was no significant difference(P ＞0. 05). HDF group and HP + HD group could all effectively eliminate the middle molecular substance PTH, but the clearance rate of HDF group was better than that of HP + HD group,the difference was statistically significant (P ＜ 0. 05 ). Conclusion HDF could safely and effectively clear PTH and had better effect than HD + HP. Key words: Chronic renal failure; Hemodialysis; Hemodiafiltration; Hemoper-fusion; Parathyroid hormone

The differences of asymmetric dimethylarginine removal by different dialysis treatments

Background: Asymmetric dimethylarginine (ADMA) as a uremia toxin is accumulated in end-stage renal disease (ESRD) patients. Elevated ADMA level has been shown to be predictive of cardiovascular diseases (CVDs) and all-cause mortality in ESRD. Therefore, we investigated the removal of ADMA by different dialysis treatments. Methods: There were 30 each of hemodialysis (HD), hemodiafiltration (HDF), peritoneal dialysis (PD) patients, and healthy volunteers enrolled. The ADMA concentrations in serum, urine, and spent dialysate samples were determined. The urine and spent dialysate volumes were recorded. The ADMA removals by urine and spent dialysate in 1 week were calculated and compared among four groups. It was also analyzed for the correlations between the total removal of ADMA in 1 week and the parameters of age, durance of dialysis, glomerular filtration rate, urine volume, urinal ADMA level, spent dialysate volume, and spent dialysate ADMA level. Results: The serum levels of ADMA in dialysis patients were much higher than in healthy subjects (0.32 ± 0.09 μmol/L), and their 1-week total removals of ADMA were much lower than healthy controls (249.21 ± 57.04 μmol/week) (p-values all were less than 0.01). Among dialysis groups, serum ADMA levels decreased significantly in PD patients compared with HD or HDF patients (1.38 ± 0.30 μmol/L vs. 1.82 ± 0.38 μmol/L and 1.63 ± 0.32 μmol/L, p < 0.01), and the total removal of ADMA diminished remarkably by turns of PD, HDF, and HD groups (47.79 ± 8.20 μmol/week, 31.79 ± 8.92 μmol/week, 14.63 ± 6.53 μmol/week, respectively, p < 0.01). The total removal of ADMA in 1 week was related directly with the spent dialysate concentrations of ADMA, the spent dialysate volume, and the urine volume. Conclusions: ADMA was mainly removed by dialysate in dialysis patients. Different dialysis models have different clearance capability on plasma ADMA. PD might be more effective on ADMA removal than HD and HDF, with HDF being more effective than HD.

Trial use of a polymethylmethacrylate membrane for the removal of free immunoglobulin light chains in dialysis patients.

Background. Free immunoglobulin light chains (FLCs) accumulate at high levels in the blood of dialysis patients and are likely to cause immunodeficiency during periods of dialysis. Our group examined the blood FLC concentration, κ/λ ratio and rates of FLC removal in different dialysis modes using different dialysis membranes.Methods. Polymethylmethacrylate (PMMA) membrane (BG-PQ, Toray) under the haemodialysis (HD) condition was used for seven chronic maintenance dialysis patients who had been treated by hemodiafiltration (HDF) (five polyester-polymer alloy (PEPA) and two polysulphone) in a crossover fashion. FLCs in serum were measured with a FREELITE™ Human Kappa Free Kit and Lambda Free Kit prepared by Binding Site, UK (supplied by Medical & Biological Laboratories Co., Ltd, Japan). Each κ-type and λ-type FLC was quantitatively measured with a Dade Behring BNII™. Western blotting was conducted using a goat anti-human κFLC polyclonal antibody.Results. The κ and λ serum FLCs in HD patients (n = 7) were 157.4 ± 88.9 and 121.9 ± 56.3 mg/L, respectively, and were accumulated in concentrations 4- to 16-fold higher than the concentrations in healthy controls. The κ/λ ratio was included in the reference range (0.26–1.65). In the HD cases dialysed with PMMA membrane, the FLCs were removed mainly by adsorption, leaving only very small quantities in the whole dialysis waste fluid. The ratio between the total removed quantity and albumin leakage ((κ+λ)/Alb) was higher in the PMMA HD group than in the HDF group, and the rate of κFLC removal was higher than the rate of λFLC removal. The serum κFLC in dialysis patients had a multimer structure. In western blotting, the adsorbed κFLC (including multimer structure) detected in the PMMA membrane exceeded that detected in the dialysate with the polysulphone membrane.Conclusions. Although the FLCs were removed at high rates under the HDF condition, they were also effectively removed by adsorption with the PMMA membrane under the HD condition. It may be possible to effectively remove the FLC multimer with a PMMA membrane via adsorption. In future studies on FLC removal in patients with chronic renal failure, it will be necessary to assess not only the quantity of simple removal from the blood but also the qualitative properties, such as the degree to which accumulation and removal rates depend on the κ/λ ratio and multimer structures.

Long-Term Outcomes in Online Hemodiafiltration and High-Flux Hemodialysis

Theoretical advantages exist of online hemodiafiltration (HDF) over high-flux hemodialysis (HD), but outcome data are scarce. Our objective was to compare outcomes between these modalities. We studied 858 incident patients in our incremental high-flux HD and online HDF program during an 18-yr period. We compared outcomes, including survival, in those who were treated predominantly with HDF (>50% sessions) and those with high-flux HD. Survival comparisons used a Cox model taking into account the time-varying proportion of time spent on HDF. All data were prospectively collected. A total of 152,043 sessions were delivered as HDF and 291,222 as high-flux HD. A total of 232 (27%) patients were treated predominantly with HDF and 626 (73%) with high-flux HD. Total Kt/V, serum albumin, erythropoietin resistance index, and BP were similar in both groups up to 5 yr after HD initiation. Intradialytic hypotension was less frequent in the predominant HDF group. Predominant HDF treatment was associated with a reduced risk for death after correction for confounding variables. In a second Cox model, proportion of time spent on HDF predicted survival, such that patients who were treated solely by HDF would have a hazard for death of 0.66 compared with those who solely used high-flux HD. We found no benefits of HDF over high-flux HD with respect to anemia management, nutrition, mineral metabolism, and BP control. The mortality benefit associated with HDF requires confirmation in large randomized, controlled trials. These data may contribute to their design.

The impact of dialysis modality on skin hyperpigmentation in haemodialysis patients

Skin hyperpigmentation in end-stage renal disease (ESRD) patients has been attributed to the accumulation of middle-molecular-weight (MMW) substances. Although an MMW mechanism suggests that hyperpigmentation may be improved by high-flux haemodialysis (HF-HD) and haemodiafiltration (HDF), this possibility has not been explored. In the present study, we investigated the impact of different dialysis modalities on skin colour in HD patients. Eighty-two ESRD patients on HD were divided into low-flux HD (LF-HD), HF-HD and HDF groups. The melanin index (MI) and erythema index (EI) of the abdomen and the flexor side of the forearm (non-sun-exposed areas) and the forehead (sun-exposed area) were determined by using a narrow-band reflectance spectrophotometer at baseline and after 12 months. Even though absolute values of baseline and follow-up MI and EI of the three sites were comparable among the three groups, forehead MI and EI were significantly decreased after 12 months in the HDF group (P < 0.05). In addition, the change in forehead MI was significantly greater in the HDF than in the LF-HD group (-1.0 +/- 2.4% versus 0.3 +/- 1.6%, P < 0.05). Moreover, beta(2)-microglobulin reduction rates were negatively correlated with both changes in forehead MI (P < 0.01) and EI (P < 0.05). Skin colour of sun-exposed areas was signi- ficantly decreased in ESRD patients receiving HDF therapy, suggesting that enhanced removal of MMW substances by convection may prevent or reduce hyperpigmentation in HD patients.

Effect of High Haematocrit on the Efficiency of High-Flux Dialysis Therapies

Background: There is a concern that high haematocrit (Hct) levels will reduce the efficiency of dialysis treatments, particularly in post-dilution haemodiafiltration (HDF) where there is the potential for intense haemoconcentration within the dialyser. Methods: We measured serial Hct and performed serial clearance measurements for urea, phosphate, β₂-microglobulin and myoglobin in 12 patients with Hct >35% on high-flux haemodialysis (HFHD) or HDF. We assessed whether changes in the intra-dialyser Hct influenced solute clearance and whether there were differences between the two modalities. Results: Hct rose significantly in all treatments studied. Convective and total solute clearances were higher in the HDF group when compared to the HFHD group. Phosphate clearance in HFHD fell towards the end of dialysis when the Hct was highest but no differences were detected for the other solutes. Conclusion: Despite marked haemoconcentration, the impact on solute clearance across the range of molecular size studied is small. These findings are reassuring in the current era of widespread erythropoietin use.

Comparison of Middle-Molecule Clearance between Convective Control Double High-Flux Hemodiafiltration and On-Line Hemodiafiltration

Hemodiafiltration (HDF) is now a well-recognized treatment modality for end-stage renal disease (ESRD) patients. It provides superior characteristics over conventional hemodialysis in many respects. On-line HDF, however, which has been mainly used in clinical practice, requires a special machine. Interestingly, the recently innovated convective-control double high-flux hemodiafiltration (CC-DHF) machine can provide HDF treatment with an adjustable convection rate by using the conventional volume-controlled dialysate flow hemodialysis machine in a modified way. The present study was conducted to compare the efficacy of CC-DHF compared to on-line HDF in terms of middle and small solute clearances in 12 stable, chronic hemodialysis patients who underwent hemodialysis three times a week for at least 6 months. The results showed that the beta 2-microglobulin (beta 2M) removal represented by the beta 2M clearance in CC-DHF was comparable to that in on-line HDF (112.4+/-17.0 vs. 119.4+/-15.5 ml/min respectively, NS). Also, the beta 2M reduction ratio in the CC-DHF group did not differ from the on-line HDF group (85.5+/-4.2% vs. 86.1+/-6.7%, NS). With regard to small solute clearances, the values of single-pool Kt/V and phosphate clearance did not differ between CC-DHF and on-line HDF groups. In conclusion, CC-DHF provides removal of beta 2M and small molecule uremic toxins that is comparable to on-line HDF. An on-line HDF machine may not be available in all hemodialysis centers, whereas CC-DHF can be easily set up, with proper precautions regarding the fluid quality. Therefore, CC-DHF can provide the benefits of convective therapy to patients in situations where use of an on-line HDF machine is limited.

Effect of hemodiafiltration on pulmonary hemodynamics in endotoxic shock.

Hemofiltration can improve pulmonary hemodynamics during septic shock. The main objective of the study was to determine whether hemodiafiltration (HDF) would also have beneficial effects on pulmonary hemodynamics during septic shock. In the Endo group, six anesthetized pigs received a 0.5 mg/kg endotoxin infusion over 30 min. In the HDF group (n = 6), HDF was started 30 min after the end of the endotoxin infusion, while in the Control group (n = 4) they received HDF but no endotoxin infusion. Pulmonary hemodynamics were analyzed in detail with a four-element windkessel model. Although in the Control group, HDF did not alter pulmonary hemodynamic parameters, in the HDF group, it was responsible for an amplification of the deleterious pulmonary vascular response to endotoxin insult. Our results show that HDF must be used cautiously in septic shock since it can precipitate right heart failure by increasing pulmonary vascular resistance.

Inflammatory response to cardiac bypass in ewe fetuses: effects of steroid administration or continuous hemodiafiltration

Objectives We sought to investigate the effectiveness of glucocorticoid administration or continuous venovenous hemodiafiltration on endothelin and corticotropin-releasing factor release or clearance during prolonged fetal cardiac bypass and on the overall performance of fetuses. Methods Circulating endothelin 1, 2, and 3 and corticotropin-releasing factor levels were measured in fetal ewes during a 60-minute cardiac bypass period performed with an inline axial flow pump. Blood samples were collected before, during, and 90 minutes after cardiac bypass. Animals were divided into 4 groups. The betamethasone group (n = 6) received maternal treatment with 12 mg of betamethasone 1 and 2 days before the experiment. The methylprednisolone group (n = 5) received fetal treatment with 40 mg/kg intravenous methylprednisolone at the beginning of cardiac bypass. The continuous venovenous hemodiafiltration group (n = 4) underwent continuous venovenous hemodiafiltration with a 0.3-m 2 polysulfone filter during cardiac bypass. The final group was the control group (n = 4). Results Maternal steroid pretreatment failed to decrease endothelin or corticotropin-releasing factor production when compared with levels in the control animals. Fetal treatment with methylprednisolone produced a significant decrease in endothelin 2 production during cardiac bypass ( P < .02) and endothelin 1 production at the end of the experiment ( P < .02). Continuous venovenous hemodiafiltration blocked completely the increase of endothelin and corticotropin-releasing factor levels during cardiac bypass ( P < .02), which was maintained 90 minutes after cardiac bypass. Acid-base balance was preserved during cardiac bypass by the continuous venovenous hemodiafiltration but worsened after disconnection of the extracorporeal circuit, whereas animals treated with methylprednisolone had better pH, Pa co 2, and bicarbonate levels by the end of the experiment. The overall tolerance of the procedure was better in the continuous venovenous hemodiafiltration group during cardiac bypass and in the methylprednisolone group at the end of the experiment. Conclusions Continuous venovenous hemodiafiltration provides sustained stability of endothelin levels during fetal cardiac bypass. This technique might help, in association with fetal steroid treatment, to contain the inflammatory response leading to postbypass placental dysfunction.

Effect of Hemodialysis and Hemodiafiltration on Uremic Neuropathy

This study was undertaken to compare the effect of 1 year hemodialysis (HD) or hemodiafiltration (HDF) treatment on peripheral neuropathy. Thus 21 of 42 patients on chronic HD (1-1.3 m2 cuprophane dialyzer, Qb 300 ml/min) were switched to HDF (1.3 m2 polysulfone dialyzer, Qb 400 ml/min, substitution volume 9-13 liters, ultrafiltration rate 60-70 ml/min), while the remaining patients were considered as a control group. Treatment time was scheduled both in HD and HDF to maintain adequate BUN levels in relation to protein catabolic rate. However, HDF provided a significantly greater weekly inulin (MW 5,000) clearance than HD (5.8 +/- 1.2 vs. 1.6 +/- 0.2 ml/min; p less than 0.001). HD and HDF groups were comparable for age, time on dialysis and starting electroneurographic parameters, which were on average within the normal range. After 1 year follow-up, creatinine, hematocrit, calcium, phosphate, PTH, BUN, protein catabolic rate and residual GFR were comparable in the two groups, whereas beta 2-microglobulin was significantly reduced in HDF patients (29 +/- 6.7 vs. 38.8 +/- 13.9 mg/l in HD patients, p less than 0.01). During the 1-year treatment, electroneurographic parameters did not change in HDF patients, whereas a significant decrease of ulnar motor nerve conduction velocity, ulnar muscle action potential amplitudes, median sensory nerve conduction velocity and peroneal muscle action potential amplitudes was detected in HD patients. We conclude that HDF might prevent the worsening of the electroneurographic indices occurring during chronic HD treatment, as it provides a more effective removal of middle and larger molecules than HD. The use of a more biocompatible membrane in HDF might further contribute to this favorable effect on uremic neuropathy.