Dynamics of Polymer Chains in Poly(ethylene oxide)/Silica Nanocomposites via a Combined Computational and Experimental Approach.

The dynamics of polymer chains in poly(ethylene oxide)/silica (PEO/SiO2) nanoparticle nanohybrids have been investigated via a combined computational and experimental approach involving atomistic molecular dynamics simulations and dielectric relaxation spectroscopy (DRS) measurements. The complementarity of the approaches allows us to study systems with different polymer molecular weights, nanoparticle radii, and compositions across a broad range of temperatures. We study the effects of spatial confinement, which is induced by the nanoparticles, and chain adsorption on the polymer's structure and dynamics. The investigation of the static properties of the nanocomposites via detailed atomistic simulations revealed a heterogeneous polymer density layer at the vicinity of the PEO/SiO2 interface that exhibited an intense maximum close to the inorganic surface, whereas the bulk density was reached for distances ∼1-1.2 nm away from the nanoparticle. For small volume fractions of nanoparticles, the polymer dynamics, probed by the atomistic simulations of low-molecular-weight chains at high temperatures, are consistent with the presence of a thin adsorbed layer that exhibits slow dynamics, with the dynamics far away from the nanoparticle being similar to those in the bulk. However, for high volume fractions of nanoparticles (strong confinement), the dynamics of all polymer chains were predicted slower than that in the bulk. On the other hand, similar dynamics were found experimentally for both the local ß-process and the segmental dynamics for high-molecular-weight systems measured at temperatures below the melting temperature of the polymer, which were probed by DRS. These differences can be attributed to various parameters, including systems of different molecular weights and nanoparticle states of dispersion, the different temperature range studied by the different methods, the potential presence of a reduced-mobility PEO/SiO2 interfacial layer that does not contribute to the dielectric spectrum, and the presence of amorphous-crystalline interfaces in the experimental samples that may lead to a different dynamical behaviors of the PEO chains.

Mechanical Behavior of Polymer Nanocomposites via Atomistic Simulations: Conformational Heterogeneity and the Role of Strain Rate.

Polymer nanohybrids with a high fraction of nanofillers have been found to exhibit improved mechanical properties compared to the neat polymer homogeneous systems. Since polymer-based materials are characterized by a broad range of relaxation times, it is expected that their response under external load would depend on the actual rate of the applied deformation. In this work, we investigate the heterogeneous mechanical behavior in glassy poly(ethylene oxide)/silica nanoparticles (PEO/SiO2) nanocomposites via detailed atomistic molecular dynamics simulations. Our goal is to unravel the effect of strain rate on the mechanism of polymer nanocomposite reinforcement, within the glassy state, by directly probing the mechanical properties at the molecular level. By applying tensile deformations with various strain rates we clearly demonstrate that the value of the applied strain rate strongly affects the mechanical properties of the PEO/SiO2 model systems, inducing a transition from a rubber-like behavior, at low strain rate, to a more brittle one, at high strain rates. Then, we further investigate the mechanical heterogeneity in glassy PEO/SiO2 systems by probing directly the stress and strain fields for various conformations of adsorbed (trains, tails, loops, and bridges), and free polymer chains. Our data emphasize the importance of both train and bridge conformations on the mechanical reinforcement of the polymer nanocomposites. Last, we also probe the mobility of various chain conformations, under different applied strain rates, and their contribution to the overall mechanical behavior of the nanocomposite, during the deformation process.

A systematic review of the efficacy and safety of anticoagulants in advanced chronic kidney disease.

BACKGROUND: Patients with chronic kidney disease (CKD) have an increased risk of venous thromboembolism (VTE) and atrial fibrillation (AF). Anticoagulants have not been studied in randomised controlled trials with CrCl < 30 ml/min. The objective of this review was to identify the impact of different anticoagulant strategies in patients with advanced CKD including dialysis. METHODS: We conducted a systematic review of randomized controlled trials and cohort studies, searching electronic databases from 1946 to 2022. Studies that evaluated both thrombotic and bleeding outcomes with anticoagulant use in CrCl < 50 ml/min were included. RESULTS: Our initial search yielded 14,503 papers with 53 suitable for inclusion. RCTs comparing direct oral anticoagulants (DOACs) versus warfarin for patients with VTE and CrCl 30-50 ml/min found no difference in recurrent VTE events (RR 0.68(95% CI 0.42-1.11)) with reduced bleeding (RR 0.65 (95% CI 0.45-0.94)). Observational data in haemodialysis suggest lower risk of recurrent VTE and major bleeding with apixaban versus warfarin. Very few studies examining outcomes were available for therapeutic and prophylactic dose low molecular weight heparin for CrCl < 30 ml/min. Findings for patients with AF on dialysis were that warfarin or DOACs had a similar or higher risk of stroke compared to no anticoagulation. For patients with AF and CrCl < 30 ml/min not on dialysis, anticoagulation should be considered on an individual basis, with limited studies suggesting DOACs may have a preferable safety profile. CONCLUSION: Further studies are still required, some ongoing, in patients with advanced CKD (CrCl < 30 ml/min) to identify the safest and most effective treatment options for VTE and AF.

Research priorities for autosomal dominant polycystic kidney disease: a UK priority setting partnership.

OBJECTIVES: Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney condition, accounting for 7%-10% of patients with kidney failure. Fundamental basic science and clinical research on ADPKD is underway worldwide but no one has yet considered which areas should be prioritised to maximise returns from limited future funding. The Polycystic Kidney Disease Charity began a priority setting partnership with the James Lind Alliance (JLA) in the UK in 2019-2020 to identify areas of uncertainty in the ADPKD care pathway and allow patients, carers and healthcare professionals to rank the 10 most important questions for research. DESIGN: The scope covered ADPKD diagnosis and management, identifying new treatments to prevent/slow disease progression and practical, integrated patient support (https://pkdcharity.org.uk/research/for-researchers/adpkd-research-priorities). We used adapted JLA methodology. Initially, an independent information specialist collated uncertainties in ADPKD care from recent consensus conference proceedings and additional literature. These were refined into indicative questions with Steering Group oversight. Finally, the 10 most important questions were established via a survey and online consensus workshop. SETTING: UK. PARTICIPANTS: 747 survey respondents (76% patients, 13% carers, 11% healthcare professionals); 23 workshop attendees. RESULTS: 117 uncertainties in ADPKD care were identified and refined into 35 indicative questions. A shortlist of 17 questions was established through the survey. Workshop participants reached agreement on the top 10 ranking. The top three questions prioritised by patients, carers and healthcare professionals centred around slowing disease progression, identifying persons for early treatment and organising care to improve outcomes. CONCLUSIONS: Our shortlist reflects the varied physical, psychological and practical challenges of living with and treating ADPKD, and perceived gaps in knowledge that impair optimal care. We propose that future ADPKD research funding takes these priorities into account to focus on the most important areas and to maximise improvements in ADPKD outcomes.

The high-volume haemodiafiltration vs high-flux haemodialysis registry trial (H4RT): a multi-centre, unblinded, randomised, parallel-group, superiority study to compare the effectiveness and cost-effectiveness of high-volume haemodiafiltration and high-flux haemodialysis in people with kidney failure on maintenance dialysis using linkage to routine healthcare databases for outcomes.

BACKGROUND: More than a third of the 65,000 people living with kidney failure in the UK attend a dialysis unit 2-5 times a week to have their blood cleaned for 3-5 h. In haemodialysis (HD), toxins are removed by diffusion, which can be enhanced using a high-flux dialyser. This can be augmented with convection, as occurs in haemodiafiltration (HDF), and improved outcomes have been reported in people who are able to achieve high volumes of convection. This study compares the clinical- and cost-effectiveness of high-volume HDF compared with high-flux HD in the treatment of kidney failure. METHODS: This is a UK-based, multi-centre, non-blinded randomised controlled trial. Adult patients already receiving HD or HDF will be randomised 1:1 to high-volume HDF (aiming for 21+ L of substitution fluid adjusted for body surface area) or high-flux HD. Exclusion criteria include lack of capacity to consent, life expectancy less than 3 months, on HD/HDF for less than 4 weeks, planned living kidney donor transplant or home dialysis scheduled within 3 months, prior intolerance of HDF and not suitable for high-volume HDF for other clinical reasons. The primary outcome is a composite of non-cancer mortality or hospital admission with a cardiovascular event or infection during follow-up (minimum 32 months, maximum 91 months) determined from routine data. Secondary outcomes include all-cause mortality, cardiovascular- and infection-related morbidity and mortality, health-related quality of life, cost-effectiveness and environmental impact. Baseline data will be collected by research personnel on-site. Follow-up data will be collected by linkage to routine healthcare databases - Hospital Episode Statistics, Civil Registration, Public Health England and the UK Renal Registry (UKRR) in England, and equivalent databases in Scotland and Wales, as necessary - and centrally administered patient-completed questionnaires. In addition, research personnel on-site will monitor for adverse events and collect data on adherence to the protocol (monthly during recruitment and quarterly during follow-up). DISCUSSION: This study will provide evidence of the effectiveness and cost-effectiveness of HD as compared to HDF for adults with kidney failure in-centre HD or HDF. It will inform management for this patient group in the UK and internationally. TRIAL REGISTRATION: ISRCTN10997319 . Registered on 10 October 2017.

Interface and Interphase in Polymer Nanocomposites with Bare and Core-Shell Gold Nanoparticles.

Metal nanoparticles are used to modify/enhance the properties of a polymer matrix for a broad range of applications in bio-nanotechnology. Here, we study the properties of polymer/gold nanoparticle (NP) nanocomposites through atomistic molecular dynamics, MD, simulations. We probe the structural, conformational and dynamical properties of polymer chains at the vicinity of a gold (Au) NP and a functionalized (core/shell) Au NP, and compare them against the behavior of bulk polyethylene (PE). The bare Au NPs were constructed via a systematic methodology starting from ab-initio calculations and an atomistic Wulff construction algorithm resulting in the crystal shape with the minimum surface energy. For the functionalized NPs the interactions between gold atoms and chemically adsorbed functional groups change their shape. As a model polymer matrix we consider polyethylene of different molecular lengths, from the oligomer to unentangled Rouse like systems. The PE/Au interaction is parametrized via DFT calculations. By computing the different properties the concept of the interface, and the interphase as well, in polymer nanocomposites with metal NPs are critically examined. Results concerning polymer density profiles, bond order parameter, segmental and terminal dynamics show clearly that the size of the interface/interphase, depends on the actual property under study. In addition, the anchored polymeric chains change the behavior/properties, and especially the chain density profile and the dynamics, of the polymer chain at the vicinity of the Au NP.

Stroke in Hemodialysis Patients Randomized to Different Intravenous Iron Strategies: A Prespecified Analysis from the PIVOTAL Trial.

Background: People with kidney failure treated with hemodialysis (HD) are at increased risk of stroke compared with similarly aged people with normal kidney function. One concern is that treatment of renal anemia might increase stroke risk. We studied risk factors for stroke in a prespecified secondary analysis of a randomized, controlled trial of intravenous iron treatment strategies in HD. Methods: We analyzed data from the Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL) trial, focusing on variables associated with risk of stroke. The trial randomized 2141 adults who had started HD <12 months earlier and who were receiving an erythropoiesis-stimulating agent (ESA) to high-dose IV iron administered proactively or low-dose IV iron administered reactively in a 1:1 ratio. Possible stroke events were independently adjudicated. We performed analyses to identify variables associated with stroke during follow-up and assessed survival following stroke. Results: During a median 2.1 years of follow-up, 69 (3.2%) patients experienced a first postrandomization stroke. Fifty-seven (82.6%) were ischemic strokes, and 12 (17.4%) were hemorrhagic strokes. There were 34 postrandomization strokes in the proactive arm and 35 postrandomization strokes in the reactive arm (hazard ratio, 0.90; 95% confidence interval, 0.56 to 1.44; P=0.66). In multivariable models, women, diabetes, history of prior stroke at baseline, higher baseline systolic BP, lower serum albumin, and higher C-reactive protein were independently associated with stroke events during follow-up. Hemoglobin, total iron, and ESA dose were not associated with risk of stroke. Fifty-eight percent of patients with a stroke event died during follow-up compared with 23% without a stroke. Conclusions: In patients on HD, stroke risk is broadly associated with risk factors previously described to increase cardiovascular risk in this population. Proactive intravenous iron does not increase stroke risk.Clinical Trial registry name and registration number: Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL), 2013-002267-25.

Establishing a tele-clinic service for kidney transplant recipients through a patient-codesigned quality improvement project.

Kidney transplant patients in our regional centre travel long distances to attend routine hospital follow-up appointments. Patients incur travel costs and productivity losses as well as adverse environmental impacts. A significant proportion of these patients, who may not require physical examination, could potentially be managed through telephone consultations (tele-clinic). We adopted a Quality Improvement approach with iterative Plan-Do-Study-Act (PDSA) cycles to test the introduction of a tele-clinic service. We codesigned the service with patients and developed a prototype delivery model that we then tested over two PDSA improvement ramps containing multiple PDSA cycles to embed the model into routine service delivery. Nineteen tele-clinics were held involving 168 kidney transplant patients (202 tele-consultations). 2.9% of tele-clinic patients did not attend compared with 6.9% for face-to-face appointments. Improving both blood test quality and availability for the tele-clinic was a major focus of activity during the project. Blood test quality for tele-clinics improved from 25% to 90.9%. 97.9% of survey respondents were satisfied overall with their tele-clinic, and 96.9% of the patients would recommend this to other patients. The tele-clinic saved 3527 miles of motorised travel in total. This equates to a saving of 1035 kgCO2. There were no unplanned admissions within 30 days of the tele-clinic appointment. The service provided an immediate saving of £6060 for commissioners due to reduced tele-clinic tariff negotiated locally (£30 less than face-to-face tariff). The project has shown that tele-clinics for kidney transplant patients are deliverable and well received by patients with a positive environmental impact and modest financial savings. It has the potential to be rolled out to other renal centres if a national tele-clinic tariff can be negotiated, and an integrated, appropriately reimbursed community phlebotomy system can be developed to facilitate remote monitoring of patients.

Increased Mortality Associated with Higher Pre-Dialysis Serum Sodium Variability: Results of the International MONitoring Dialysis Outcome Initiative.

BACKGROUND: Low serum sodium (SNa) is associated with an increased mortality in chronic hemodialysis (HD) patients. Dialysis patients are thought to have an individual pre-dialysis SNa set-point, yet there is evidence for variability of pre-dialysis SNa in individual patient. In this study, we explored the association of several SNa variability metrics with all-cause mortality in a large patient population from the international MONitoring Dialysis Outcomes (MONDO) Initiative. METHODS: All adult incident patients from the MONDO database with more than 5 SNa measurements during the first year on HD were included. All patients were required to survive the first year on HD (defined as the baseline). During the subsequent 2 years of follow-up, all-cause mortality was recorded. The following variability indicators were calculated during baseline: mean SNa and its SD; average real variability (ARV, average the absolute distance of the 2 consecutive SNa measurements), and average directional range (DR, the difference between minimum and maximum values). We used Cox Proportional hazard model with bivariate spline terms to analyze the joint association of SNa and SD, ARV and DR, respectively, with all-cause mortality. While conducting the multivariate Cox regression analyses, patients were stratified into 3 groups of DR (Negative DR: -20≤ DR ≤ -6, Null DR: -6< DR < 6 and Positive DR: 6≤ DR ≤20) with the Null DR as the reference group. RESULTS: We included 20,216 patients in the study. A SNa ≤135 mEq/L was observed to be the strongest predictor of evaluated mortality risk. Higher SNa variability (quantified as SD, ARV, and DR) was also associated with an increased mortality irrespective of SNa levels. When compared with higher SD or ARV, greater DR showed a stronger association with an elevated risk of death. Controlling the Cox Proportional hazard models for additional parameters showed consistent results. CONCLUSION: Higher SNa variability associated with increased all-cause mortality at all levels of SNa. DR of SNa showed the strongest association with mortality and may constitute a Simple and novel prognostic indicator, easily applicable at the bedside.

Association between Heights of Dialysis Patients and Outcomes: Results from a Retrospective Cohort Study of the International MONitoring Dialysis Outcomes (MONDO) Database Initiative.

BACKGROUND: Tall people have improved metabolic profiles and better cardiovascular outcomes, a relationship inverted in dialysis patients. We investigated the relationship between height and outcomes in incident hemodialysis (HD) patients commencing treatment in an analysis of the international Monitoring Dialysis Outcomes (MONDO) database. METHODS: In this retrospective cohort study, we included incident HD patients commencing treatment between -January 1, 2006 and December 31, 2010 and investigated the association between height and mortality using the MONDO database. A 6-months baseline period preceded 2.5 years of follow-up, during which we recorded patient mortality. Patients were stratified in region-specific deciles of the respective database's population (Asia Pacific, North and South America, and Europe) and we developed Cox-proportional hazard models (additionally adjusted for age, gender, post-dialysis weight, eKt/V, albumin, interdialytic weight gain, phosphorus, and predialysis systolic blood pressure) for each database. RESULTS: We studied 23,353 patients (62 ± 15 years old, 42% female, body mass index 26 ± 6 kg/m2, height 165 ± 10 cm). We found a trend of increasing hazard ratio of death (HR) with increasing height for Asia Pacific, Europe, and South America. In the fully adjusted models, for South America, we found a trend of increasing HR without significance among deciles >5. In Europe, deciles 8-10 had significantly increased HR. No clear trend was found in North America. CONCLUSION: We found an increasing risk of death with increasing height in all regions, except North America. While the reasons remain unclear, further research may be warranted.

Dialysis Access as an Area of Improvement in Elderly Incident Hemodialysis Patients: Results from a Cohort Study from the International Monitoring Dialysis Outcomes Initiative.

BACKGROUND: Commencing hemodialysis (HD) using a catheter is associated with a higher risk of adverse outcomes, and early conversion from central-venous catheter (CVC) to arteriovenous fistula/graft (non-CVC) improves outcomes. We investigated CVC prevalence and conversion, and their effects on outcomes during the first year of HD in a multinational cohort of elderly patients. METHODS: Patients ≥70 years from the MONDO Initiative who commenced HD between 2000 and 2010 in Asia-Pacific, Europe, North-, and South-America and survived at least 6 months were included in this investigation. We stratified by age (70-79 years [younger] vs. ≥80 years [older]) and compared access types (at first and last available date) and their changes. We studied the association between access at initiation and conversion, respectively, and all-cause mortality using Kaplan-Meier curve and Cox regression, and predicted the absence of conversion from catheter to non-CVC using adjusted logistic regression. RESULTS: In 14,966 elderly, incident HD patients, survival was significantly worse when using a CVC at all times. In Europe, the conversion frequency from CVC to non-CVC was higher in the younger fraction. Conversion from non-CVC to CVC was associated with worsened outcomes only in the older fraction. CONCLUSION: These results corroborate the need for early HD preparation in the elderly HD population. Treatment of elderly patients who commence HD with a CVC should be planned considering aspects of individual clinical risk assessment. Differences in treatment practices in predialysis care specific to the elderly as a population may influence access care and conversion rate.

Haemodialysis and haemodiafiltration lead to similar changes in vascular stiffness during treatment.

BACKGROUND: Haemodiafiltration (HDF) has been reported to cause less hypotension than haemodialysis (HD). We hypothesized that HDF causes less change in vascular tone, thereby reducing hypotension. METHODS: Aortic pulse wave velocity (PWVao) was measured in 284 patients, during a single dialysis session using cooled dialysate (117 HD, 177 HDF). Patient groups were matched for age, sex and cardiovascular comorbidity. RESULTS: Systolic blood pressure (SBP) declined from 144 ± 26 to 133 ± 26 after 20 minutes, and to 131 ± 26 mmHg post HD, and for HDF from 152 ± 26 to 143 ± 27 after 20 minutes, then to 138 ± 27 mmHg post HDF. Net Ultrafiltration rates to achieve weight loss were similar; HD 0.13 ± 0.06 vs HDF 0.12 ± 0.05 mL/kg/min. PWVao did not change after 20 minutes HD 0.42(-0.7 to 1.3), HDF 0.5 (-0.6 to 1.8) or at the end of the session: HD -0.39 (1.5 to 1.2), HDF -0.41(-2.0 to 1.3) m/s. Aortic augmentation index (AiAxo), assessment of vascular tone fell significantly with both HD; 20 minutes by 6.2 (-2.5 to 14), end 5.6 (-6.7 to 13.9), and HDF 20 min by 4.2 (-2.5 to 10), end 7.8 (-0.8 to 19.3), with no difference between HD and HDF. The ultrafiltration rate correlated with % change in aortic SBP (r = 0.28 p = 0.004), but not with changes in PWVao or augmentation indices. CONCLUSIONS: Blood pressure declined during both HD and HDF treatments, as did augmentation indices, unrelated to weight loss, suggesting a reduction in vascular stiffness occurs independently of treatment modality. We did not observe an advantage for HDF.

Hemodialysis outcomes in a global sample of children and young adult hemodialysis patients: the PICCOLO MONDO cohort.

BACKGROUND: The aim of this study was to describe the experience of pediatric and young adult hemodialysis (HD) patients from a global cohort. METHODS: The Pediatric Investigation and Close Collaborative Consortium for Ongoing Life Outcomes for MONitoring Dialysis Outcomes (PICCOLO MONDO) study provided de-identified electronic information of 3244 patients, ages 0-30 years from 2000 to 2012 in four regions: Asia, Europe, North America and South America. The study sample was categorized into pediatric (≤18 years old) and young adult (19-30 years old) groups based on the age at dialysis initiation. RESULTS: For those with known end-stage renal disease etiology, glomerular disease was the most common diagnosis in children and young adults. Using Europe as a reference group, North America [odds ratio (OR) 2.69; CI 1.29, 5.63] and South America (OR 4.21; CI 2.32, 7.63) had the greatest mortality among young adults. North America also had higher rates of overweight, obesity, hypertension, cardiovascular disease, hospitalizations and secondary diabetes compared with all other regions. Initial catheter use was greater for North American (86.4% in pediatric patients and 75.2% in young adults) and South America (80.6% in pediatric patients and 75.9% in young adults). Catheter use at 1-year follow-up was most common in North American children (77.3%) and young adults (62.9%). Asia had the lowest rate of catheter use. For both age groups, dialysis adequacy (equilibrated Kt/V) ranged between 1.4 and 1.5. In Asia, patients in both age groups had significantly longer treatment times than in any other region. CONCLUSIONS: The PICCOLO MONDO study has provided unique baseline and 1-year follow-up information on children and young adults receiving HD around the globe. This cohort has brought to light aspects of care in these age groups that warrant further investigation.

Changes in Vascular Tone Occur Early During Hemodialysis Treatments Independently of Volume Reduction.

Hypotension commonly occurs during hemodialysis (HD). Hypotension can result from an absolute reduction in plasma volume following excessive ultrafiltration or from a reduction in vascular tone. We hypothesized that changes in vascular tone could occur during dialysis. Aortic pulse wave velocity (aPWV) was measured in 197 HD patients, mean age 63.3 ± 16.6 years, 62% male, 49% diabetic, during a single HD session. aPWV did not change (9.6 ± 2.2 vs. 9.6 ± 2.2 m/s) with HD. Systolic blood pressure (SBP) declined from 151 ± 31 to 147 ± 32 after 20 min and to 140 ± 36 mm Hg on completion of HD (P < 0.05), with an ultrafiltration volume of 2.2 ± 0.9 L over a 3.9 ± 0.4 h HD session. Aortic SBP declined from 154 ± 32 to 146 ± 29 after 20 min and 143 ± 35 at the end of HD, P < 0.001. Aortic augmentation index (Aortic Aix) decreased from 65% (52-79%) to 36.7% (23.3-52.9%) by 20 min and to 34.3 (15.1-49.1%) on completion of HD (P < 0.05), and brachial augmentation index (brachial Aix) from 5.7% (-25.2 to 27.5%) to -1.9% (-2.2 to 30.1%) and -6.6% (-44 to 22.7%), respectively, P < 0.05. Diastolic reflection area (DRA) increased from 36.7 (27.9-46.3) to 40.4 (32.2-51) after 20 min and 47.1 (34.2-60.5) on completion of HD, P < 0.05. We report changes in arterial tone within 20 min of starting HD, when minimal ultrafiltration has occurred, suggesting that volume changes may not be the only predisposing cause of intradialytic hypotension. The combination of a fall in SBP and a rise in DRA would suggest a reduction in coronary blood flow in keeping with reports of "myocardial stunning" during HD.

SURVEY OF STAFF OPINIONS ABOUT EXTENDED HAEMODIALYSIS TREATMENT TIME AND SERVICE IMPLICATIONS.

BACKGROUND: We explored the potential impact of staff opinions and service provision upon patient's willingness to recruit to a clinical trial studying the effects of extended treatment time (TT) on haemodialysis (HD), six hours versus four hours for a period of twenty-four weeks. METHODS: We conducted a local survey of dialysis nurses and a national survey of multidisciplinary HD staff opinions to extended TT including clinical benefits, tolerance to, prescription and ability to accommodate extended TT on in-centre HD programmes. RESULTS: The survey was completed by 56/134 (42%) local nurses and the national survey by 15/72 (21%) of dialysis providers across the UK (35% nurses and 75% other healthcare professionals). The majority of respondents felt extended TT was clinically beneficial but only 42% of nurses would recommend extended TT compared to 95% of non-nursing healthcare professionals (p < 0.0001). Although 45% of nurses felt that it was well tolerated, non-nursing healthcare professionals suggested this was significantly higher at 75% (p < 0.05). The negative impact on service provision was agreed by 83% of nurses with the need to facilitate shifts within a finite time period and pressure to find session spaces being cited. CONCLUSION: There is conflict between the understanding that extended TT is clinically beneficial and its prescription & delivery to patients. Enrolment to studies examining HD delivery strategies may be influenced by service provision and staff attitudes. In centre HD has been designed to maximise patient throughput and we may need to consider more flexible settings in which to deliver longer treatment time: Home HD maybe a solution.

Incidence, risk factors, and outcomes of stroke post-transplantation in patients receiving a steroid sparing immunosuppression protocol.

Corticosteroid use after transplantation is associated with an increased incidence of cardiovascular events and death. Cerebrovascular disease is a common cause of morbidity and mortality post-renal transplantation; however, a dedicated analysis of cerebrovascular disease in recipients of a steroid sparing protocol has not been reported. The aim of this study was to examine the incidence, risk factors, and outcomes of CVA in transplant recipients receiving a steroid sparing protocol. We retrospectively analyzed 1237 patients who received a kidney alone or a simultaneous pancreas and kidney (SPK) transplant. Fifty-six of 1237 (4.53%) patients had a CVA post-transplant. All-cause mortality was significantly higher in the CVA group compared with the non-CVA group, OR: 3.4 (1.7-7.0), p < 0.001. Factors found to be associated with increased risk of CVA by multivariate analysis were older age, HR: 1.07 (1.04-1.09), p < 0.001; diabetes at the time of transplantation, HR: 2.83 (1.42-5.64), p = 0.003; corticosteroid use pre-transplant, HR: 3.27 (1.29-8.27), p = 0.013 and recipients of a SPK, HR: 4.03 (1.85-8.79), p < 0.001. This study has identified subgroups of patients who are at increased risk of CVA post-transplant in patients otherwise receiving a steroid sparing immunosuppression protocol.

Comparison of Tesio and LifeCath twin permanent hemodialysis catheters: the VyTes randomized trial.

PURPOSE: Central venous catheters for maintenance hemodialysis (HD) are designed to attain the required dialysis dose through sustained high blood flow rates (BFR). The authors studied the immediate and long-term performance and complications of two twin-catheter systems, the Tesio catheter (TC) and the LifeCath Twin (LC), to inform clinical practice. METHODS: This single-center randomized controlled parallel-group trial allocated 80 incident patients (1:1) to receive either a TC (MedComp) or LC (Vygon). Patients were dialyzed to target BFR 450 mL/min and followed up for 12 months. The primary outcome was achievement of target BFR during the first HD session. Secondary outcomes included thrombotic dysfunction, displacement and catheter-related infection. Catheter dysfunction was defined by a BFR ≤ 250 mL/min. RESULTS: More LCs reached the primary endpoint (44% vs. 10%, p=0.001) delivering a higher BFR (mean 383±82 vs. 277±79 mL/min, p<0.001). Significant differences in BFR persisted until the fourth dialysis session. Rates of catheter-related bacteremia (0.40 vs. 0.51/1,000 catheter days, p=0.7) and exit site infection were similar between groups (0.24 vs. 0.09/1,000 catheter days, p=0.4). Overall rates of catheter dysfunction were 2.8/1,000 catheter days (95% CI 2.1-3.5), with no differences in thrombolytic lock use although the LC group required more thrombolytic infusions (6 vs. 0, p=0.01). CONCLUSIONS: The LC can deliver greater BFRs in the first three HD sessions following insertion although this did not translate into differences in performance, dialysis adequacy or complication rates with long-term use. Both catheter types can consistently deliver high BFRs over an extended period of time.

Haemodialysis: hospital or home?

Healthcare costs associated with the provision of dialysis therapy are escalating globally as the number of patients developing end-stage renal disease increases. In this setting, there has been heightened interest in the application and potential benefit of home haemodialysis therapies compared with the conventional approach of thrice weekly, incentre treatments. Increasingly, national healthcare systems are financially incentivising the expansion of home haemodialysis programmes with observational studies demonstrating better patient survival, superior control of circulating volume and blood pressure, greater patient satisfaction and lower running costs compared with incentre dialysis. Nonetheless, increasing the prevalence of home haemodialysis is challenged by the technological complexity of conventional dialysis systems, the need for significant adaptations to the home as well as suboptimal clinician and patient education about the feasibility and availability of this modality. In addition, enthusiasm about frequent as well as nocturnal (extended-hours) haemodialysis has been tempered by results from the recent Frequent Haemodialysis Network randomised controlled trials comparing these schedules with a conventional incentre regime. An increasing emphasis on empowering patient choice and promoting self-management of chronic illness is a powerful driver for the expansion of home haemodialysis programmes in the UK and internationally.

Acute stroke thrombolysis in end-stage renal disease: a national survey of nephrologist opinion.

BACKGROUND/AIMS: Systemic thrombolysis for acute ischaemic stroke is the standard of care in the UK. In the absence of trial data on the safety and efficacy of this treatment in patients with end-stage renal disease, we captured the views of UK nephrologists to highlight health care policy and research objectives. METHODS: Consultant nephrologists participated in an internet-based questionnaire. Respondents were asked about their involvement in thrombolysis decisions, safety concerns in dialysis patients, views on stroke rehabilitation and opinions on antiplatelet and warfarin use for stroke prevention. RESULTS: 122/433 (28%) clinicians responded. 75% wanted involvement in thrombolysis decisions although just 10% gave input in practice. 64% expressed a high degree of concern (≥7/10) regarding intracranial bleeding risk in haemodialysis (HD). Overall risks of intra- and extracranial bleeding were rated lower in peritoneal dialysis (PD; p < 0.001). 85% felt the HD schedule impacted negatively on rehabilitation, whereas 63% felt this was the case in the context of PD (p = 0.001). More clinicians favoured warfarin for stroke prevention in PD patients with atrial fibrillation in comparison with HD patients (79 vs. 66%, p = 0.04). CONCLUSION: The majority of nephrologists want involvement in thrombolysis decisions relevant to their patients. Concerns about bleeding risks with thrombolysis are high and we identify a vital need to improve access to stroke rehabilitation in the UK, especially in HD patients.