Background:Optimal fluid status is an important issue in hemodialysis. Clinical evaluation of volume status and different diagnostic tools are used to determine hydration status in these patients. However, there is still no accurate method for this assessment. Purpose:To propose and evaluate relative lean water signal (LWSrel) as a water-fat MRI-based tissue hydration measurement. Study Type:Prospective. Population:A total of 16 healthy subjects (56 & PLUSMN; 6 years, 0 male) and 11 dialysis patients (60.3 +/- 12.3 years, 9 male; dialysis time per week 15 +/- 3.5 hours, dialysis duration 31.4 +/- 27.9 months). Field Strength/Sequence:A 3 T; 3D spoiled gradient echo. Assessment:LWSrel, a measurement of the water concentration of tissue, was estimated from fat-referenced MR images. Segmentations of total adipose tissue as well as thigh and calf muscles were used to measure LWSrel and tissue volumes. LWSrel was compared between healthy subjects and dialysis patients, the latter before and after dialysis. Bioimpedance-based body composition monitor over hydration (BCM OH) was also measured. Statistical Tests:T-tests were used to compare differences between the healthy subjects and dialysis patients, as well as changes between before and after dialysis. Pearson correlation was calculated between MRI and non-MRI biomarkers. A P value < 0.05 was considered statistically significant. Results:The LWSrel in adipose tissue was significantly higher in the dialysis cohort compared with the healthy cohort (246.8% +/- 60.0% vs. 100.0% +/- 10.8%) and decreased significantly after dialysis (246.8 +/- 60.0% vs. 233.8 +/- 63.4%). Thigh and calf muscle volumes also significantly decreased by 3.78% +/- 1.73% and 2.02% +/- 2.50% after dialysis. There was a significant correlation between changes in adipose tissue LWSrel and ultrafiltration volume (r = 87), as well as with BCM OH (r = 0.66). Data Conclusion:MRI-based LWSrel and tissue volume measurements are sensitive to tissue hydration changes occurring during dialysis.

Aims and objectives The aim of this study was to describe the basis for choosing a cannulation technique for arteriovenous fistula. Background Four cannulation techniques are relevant to cannulating an arteriovenous fistula: rope ladder, area puncture and buttonhole using blunt or sharp needles. The chosen technique may affect both the patency and number of complications. Design The study used a convergent mixed methods design and inductive approach. Methods A questionnaire and an inquiry of local guidelines were sent to nurses in all dialysis units in Sweden. Questionnaires were answered by nurses from 37 units, and 29 units included their local guidelines. The questionnaires were analysed using descriptive statistics and qualitative content analysis, and the guidelines were analysed using qualitative content analysis. The different analyses were combined in a final result. The study is based on GRAMMS guidelines. Results Local guidelines, patients and nurses own judgement, and consultation with colleagues were found to greatly influence the choice of cannulation technique. Buttonhole was the most preferred cannulation technique in the participating units and was favoured by nurses when choosing a cannulation technique. The process of choosing a cannulation technique was found to be influenced by the dedication to good cannulation technique and healthy arteriovenous fistulas, whether the technique is perceived as being easy to use and is expected to prevent complications and based on the experienced-based knowledge of each dialysis unit. Conclusions Choosing a cannulation technique is a process based on the nurse, local guidelines and the patient. Most dialysis nurses and units in Sweden consider buttonhole to be a good cannulation technique and use it as their standard technique. Relevance to clinical practice The results provide insight into why cannulation techniques are chosen differently in different units. The results also show the importance of evidence in making decisions on cannulation technique.

Background The prognosis for kidney survival is poor in patients presenting with circulating anti-glomerular basement membrane (GBM) antibodies and severe kidney injury. It is unknown if treat-ment with an endopeptidase that cleaves circulating and kidney bound IgG can alter the prognosis.& nbsp;Methods An investigator-driven phase 2a one-arm study (EudraCT 2016-004082-39) was performed in 17 hospitals in five European countries. A single dose of 0.25 mg/kg of imlifidase was given to 15 adults with circulating anti-GBM antibodies and an eGFR < 15 ml/min per 1.73m(2). All patients received standard treatment with cyclophosphamide and corticosteroids, but plasma exchange only if autoantibodies rebounded. The primary outcomes were safety and dialysis independency at 6 months.& nbsp;Results At inclusion, ten patients were dialysis dependent and the other five had eGFR levels between 7 and 14 ml/min per 1.73m(2). The median age was 61 years (range 19-77), six were women, and six were also positive for anti-neutrophil cytoplasmic antibodies. Then 6 hours after imlifidase infusion, all patients had anti-GBM antibodies levels below the reference range of a prespecified assay. At 6 months 67% (ten out of 15) were dialysis independent. This is significantly higher compared with 18% (nine out of 50) in a historical control cohort (P < 0.001, Fishers exact test). Eight serious adverse events (including one death) were reported, none assessed as probably or possibly related to the study drug.& nbsp;Conclusions In this pilot study, the use of imlifidase was associated with a better outcome compared with earlier publications, without major safety issues, but the findings need to be confirmed in a randomized controlled trial.

Background The four cannulation techniques, rope ladder (RL), area puncture (AP), buttonhole with blunt needles (BHb), and buttonhole with sharp needles (BHs), affects the arteriovenous fistula (AVF) in different ways. The aim of this study was to describe the relationship between the different cannulation techniques and the occurrence of AVF complications. Methods The study was performed as a national registry-based cohort study using data from the Swedish Renal Registry (SRR). Data were collected from January 2014 to October 2019. Seventy of Swedens dialysis units participate in the registry. We analyzed a total of 1328 AVFs in this study. The risk of complications was compared between the four different cannulation techniques. The risk of AVF complications was measured by the incidence and incidence rate ratio (IRR). We compared the IRRs of complications between different cannulation techniques. Results BHs is the most common cannulation technique in Sweden. It has been used in 55% of the AVFs at some point during their functional patency. BHb (29%), RL (13%), and AP (3%) has been used less. BHb had the lowest risk of complications compared to the other techniques, and a significantly lower risk of stenosis, infiltration, cannulation difficulties, compared to RL and BHs. Cannulation difficulties were significantly more common using AP compared to BHs, and BHb. Infections were not significantly increased using the buttonhole technique. Conclusions BHb had the lowest risk of complications. Infections were not significantly increased using the buttonhole technique. Dialysis units with a low infection rate may continue to use the buttonhole technique, as the risk of complications is lower.

Tryptophan is an essential dietary amino acid that originates uremic toxins that contribute to end-stage kidney disease (ESKD) patient outcomes. We evaluated serum levels and removal during haemodialysis and haemodiafiltration of tryptophan and tryptophan-derived uremic toxins, indoxyl sulfate (IS) and indole acetic acid (IAA), in ESKD patients in different dialysis treatment settings. This prospective multicentre study in four European dialysis centres enrolled 78 patients with ESKD. Blood and spent dialysate samples obtained during dialysis were analysed with high-performance liquid chromatography to assess uremic solutes, their reduction ratio (RR) and total removed solute (TRS). Mean free serum tryptophan and IS concentrations increased, and concentration of IAA decreased over pre-dialysis levels (67%, 49%, -0.8%, respectively) during the first hour of dialysis. While mean serum total urea, IS and IAA concentrations decreased during dialysis (-72%, -39%, -43%, respectively), serum tryptophan levels increased, resulting in negative RR (-8%) towards the end of the dialysis session (p < 0.001), despite remarkable Trp losses in dialysate. RR and TRS values based on serum (total, free) and dialysate solute concentrations were lower for conventional low-flux dialysis (p < 0.001). High-efficiency haemodiafiltration resulted in 80% higher Trp losses than conventional low-flux dialysis, despite similar neutral Trp RR values. In conclusion, serum Trp concentrations and RR behave differently from uremic solutes IS, IAA and urea and Trp RR did not reflect dialysis Trp losses. Conventional low-flux dialysis may not adequately clear Trp-related uremic toxins while high efficiency haemodiafiltration increased Trp losses.

Rapid progression of vascular calcification (VC) in hemodialysis (HD) patients is caused by several factors including inflammation and an imbalance between active inducers and inhibitors of VC. Growing evidence shows that online hemodiafiltration (ol-HDF), a combination of diffusive and convective solute transport, has positive effects on the uremic environment that affects patients on dialysis. However, we recently reported that serum 25-hydroxyvitamin D (25(OH)D) decreased after a switch from HD to ol-HDF. As a consequence of this finding, the present study was undertaken to investigate if inducers and inhibitors of VC (i.e. the inactive matrix Gla protein fractions dp-ucMGP and t-ucMGP, fetuin-A, Gla-rich protein (GRP), osteopontin (OPN), bone-specific alkaline phosphatase (BALP), and osteoprotegerin (OPG)) also are affected by ol-HDF. This non-comparative prospective study comprised 35 prevalent patients who were investigated 6, 12, and 24 months after their switch from HD to ol-HDF. Most patients had increased levels of the calcification inhibitors OPN and OPG; and of the inactive calcification inhibitor dp-ucMGP during the study period irrespective of the dialysis modality. BALP and t-ucMGP were mostly within the reference interval, but fetuin-A was mostly below the reference interval during the study period. OPN was significantly associated with BALP and parathyroid hormone, r = 0.62 and r = 0.65 (p amp;lt; .001), respectively. In conclusion, in contrast to decreased 25(OH)D levels, no differences were found for any of the measured biomarkers of VC following the switch from HD to ol-HDF. Further studies are needed to elucidate how these biomarkers can contribute to calcification risk assessment.

Survival among hemodialysis patients is disturbingly low, partly because vascular calcification (VC) and cardiovascular disease are highly prevalent. Elevated serum phosphorus (P) and calcium (Ca) levels play an essential role in the formation of VC events. The purpose of the current study was to reveal optical monitoring possibilities of serum P and Ca values during dialysis. Twenty-eight patients from Tallinn (Estonia) and Linköping (Sweden) were included in the study. The serum levels of Ca and P on the basis of optical information, i.e., absorbance and fluorescence of the spent dialysate (optical method) were assessed. Obtained levels were compared in means and SD. The mean serum level of Ca was 2.54 ± 0.21 and 2.53 ± 0.19 mmol/L; P levels varied between 1.08 ± 0.51 and 1.08 ± 0.48 mmol/L, measured in the laboratory and estimated by the optical method respectively. The levels achieved were not significantly different (p = 0.5). The Bland-Altman 95% limits of agreement between the two methods varied from -0.19 to 0.19 for Ca and from -0.37 to 0.37 in the case of P. In conclusion, optical monitoring of the spent dialysate for assessing the serum levels of Ca and P during dialysis seems to be feasible and could offer valuable and continuous information to medical staff.

BACKGROUND/AIMS: Vitamin D deficiency and elevated serum fibroblast growth factor-23 (FGF23) levels are hallmark features and surrogate markers of adverse clinical outcomes in patients with chronic kidney disease (CKD). Convection of molecules over the dialysis membrane during online hemodiafiltration (ol-HDF) increases the removal of larger waste molecules compared with traditional high-flux hemodialysis (HD). The primary aim of this study was to explore the long-term impact of ol-HDF on serum 25(OH)D and FGF23.

METHOD: An observational, prospective, noncomparator study including 35 patients who were switched from HD to ol-HDF. Serum 25(OH)D and FGF23 were measured at baseline (i.e., time of switch to ol-HDF) and at 6, 12, and 24 months.

RESULTS: At follow-up time points, there was a significant reduction in serum 25(OH)D compared with baseline (p < 0.0001) whereas FGF23 was unaltered (p > 0.05). The decrease in 25(OH)D was more prominent in individuals with higher baseline 25(OH)D levels.

CONCLUSION: Ol-HDF may lower systemic 25(OH)D levels by convective mechanisms although the clinical significance remains unknown. Further controlled studies are warranted to replicate these findings in larger patient cohorts.

BACKGROUND: Currently, urea reduction seems to be the most widely used dialysis dose parameter. The aim of this study was to investigate the possibility to monitor beta 2-microglobulin (β2-M) elimination by utilizing the ultraviolet (UV) absorbance of spent dialysate.

METHODS: Blood and spent dialysate were collected during two week's sessions in 8 patients, one week in hemodialysis (HD) and one in hemodiafiltration (HDF). Correlation analysis between UV-wavelengths and concentrations of solutes in spent dialysate was performed. The reduction ratio (RR) of concentrations in blood, dialysate and UV-absorbance were compared.

RESULTS: Differences between HD and HDF were discovered in wavelength correlation maxima for the solutes. Relative error in RR (%) was larger (p < 0.05) for β2-M than for the other solutes. The most reasonable explanation is that β2-M does not absorb UV-radiation; instead, the absorbance of surrogate substances is measured.

CONCLUSION: A high correlation between UV-absorbance and β2-M can be achieved for HDF but not for HD. Still, UV-absorbance could perhaps be used in solely HDF mode for estimation of β2-M removal. © 2015 S. Karger AG, Basel.