Geographical access to hemodialysis: an analysis of patient choices

Introduction

Patients do not always go to the facility closest to their home.

Description

A study was carried out in Provence-Alpes Côtes d'Azur (PACA) on patients' preferences to mobilize the hemodialysis offer.

Methods

The data were extracted from the REIN Registry. Potential access was compared with actual access. A survey was carried out among a sample of patients travelling an additional distance of more than 25 km.

Results

About a quarter of the patients did not travel to the nearest facility. Of these, 16.3% travelled an additional distance of over 25 km. Patients' choices were determined by the relationship of trust with the team that first set up dialysis, followed by their desire to be followed in a multi-purpose facility.

Discussion

While distance remained the decisive factor, human factors were cited in the majority of cases to explain the bypass.

Conclusion

The links between the first team and the next one should be strengthened.

Vibration-induced streaming flow near a sharp edge: Flow structure and instabilities in a large span of forcing amplitude

The steady streaming generated near solid walls by the periodic forcing of a viscous fluid is known to be strongly enhanced near sharp structures, owing to centrifugal effects that lead to the generation of an intense jet from the sharp tip. This flow has been shown to provide efficient active mixing in microchannels, due to strong transverse velocity. The forcing is often prescribed by acoustic transducers, but it can also be generated from low-frequency time-periodic flow ensured by mechanical vibrations. In this paper, we study the flow structure generated by low-frequency forcing (typically 10 Hz) around a sharp tip. Using direct numerical simulations, we extract both the time-periodic and steady responses within a large span of amplitude of vibrations. When the amplitude is smaller than the tip radius of curvature, we recover the flow structure observed at higher frequencies (>1 kHz) in previous studies, namely, an intense symmetric central jet and a quadratic dependence for the characteristic streaming velocity with the oscillating velocity v_{s}∼v_{a}^{2}. At higher amplitudes, such a scaling no longer holds and the streaming flow pattern loses its left-right symmetry. We then analyze the mechanisms of the instability from the careful examination of the instationary flow fields, and we propose possible mechanisms for such a flow transition involving the coupling between the streaming jet and instationary vorticity.

Rheopheresis Performed in Hemodialysis Patients Targets Endothelium and Has an Acute Anti-Inflammatory Effect

Background: Rheopheresis is a double-filtration plasmapheresis that removes a defined spectrum of high-molecular-weight proteins to lower plasma viscosity and improves microcirculation disorders. This technique can be performed in hemodialysis (HD) patients with severe microischemia. Interestingly, some studies showed that rheopheresis sessions improve endothelial function. Methods: Our study evaluated the inflammatory and endothelial biomarker evolution in 23 HD patients treated or not with rheopheresis. A p value ≤ 0.001 was considered statistically significant. Results: Thirteen HD patients treated by rheopheresis either for a severe peripheral arterial disease (N = 8) or calciphylaxis (N = 5) were analyzed. Ten control HD patients were also included in order to avoid any misinterpretation of the rheopheresis effects in regard to the HD circuit. In the HD group without rheopheresis, the circulating endothelial adhesion molecules, cytokines, angiogenic factor concentrations, and circulating levels were not modified. In the HD group with rheopheresis, the circulating endothelial adhesion molecules (sVCAM-1, sP-selectin, and sE-selectin) experienced a significant reduction, except sICAM-1. Among the pro-inflammatory cytokines, TNF-α was significantly reduced by 32.6% [(−42.2)−(−22.5)] (p < 0.0001), while the anti-inflammatory cytokine IL-10 increased by 674% (306−1299) (p < 0.0001). Among the angiogenic factors, only sEndoglin experienced a significant reduction. The CEC level trended to increase from 13 (3−33) cells/mL to 43 (8−140) cells/mL (p = 0.002). We did not observe any difference on the pre-session values of the molecules of interest between the first rheopheresis session and the last rheopheresis session. Conclusion: Rheopheresis immediately modified the inflammation balance and the endothelial injury biomarkers. Further studies are needed to understand the mechanisms underlying these biological observations.

Neutrophil:lymphocyte ratio correlates with the uremic toxin indoxyl sulfate and predicts the risk of death in patients on hemodialysis

BACKGROUND

Chronic kidney disease (CKD) is a major public health issue associated with increased cardiovascular, infectious and all-cause mortality. The neutrophil:lymphocyte ratio (NLR) is a predictive marker of the risk of death and cardiovascular events. Uremic toxins, notably indoxyl sulfate (IS), are involved in immune deficiency and cardiovascular complications associated with CKD. The aim of this study was to assess whether the NLR was related to uremic toxins and could predict clinical outcome in hemodialysis (HD) patients.

METHODS

We conducted a prospective cohort study of 183 patients on chronic HD. The main objective was to study the correlation between the NLR and uremic toxin serum levels. The secondary objective was to test if the NLR can predict the incidence of mortality, cardiovascular events and infectious events.

RESULTS

Patients were separated into two groups according to the NLR median value (3.49). The NLR at inclusion was correlated with the NLR at the 6-month (r = 0.55, P < 0.0001) and 12-month (r = 0.62, P < 0.0001) follow-up. Among uremic toxins, IS levels were higher in the group with high NLR (104 µmol/L versus 81 µmol/L; P = 0.004). In multivariate analysis, the NLR remained correlated with IS (P = 0.03). The incidence of death, cardiovascular events and severe infectious events was higher in the group with high NLR [respectively, 38% versus 18% (P = 0.004), 45% versus 26% (P = 0.01) and 33% versus 21% (P = 0.02)] than in the low NLR group. Multivariate analysis showed an independent association of the NLR with mortality (P = 0.02) and cardiovascular events (P = 0.03) but not with severe infectious events.

CONCLUSIONS

In HD patients, the NLR predicted mortality and cardiovascular events but not severe infections and correlated positively with the level of the uremic toxin IS. The NLR could be an interesting marker for monitoring the risk of clinical events in CKD patients.

Protein/Fiber Index Modulates Uremic Toxin Concentrations in Hemodialysis Patients

Background: Indoxyl sulfate (IS) and p-cresyl sulfate (PCS), two uremic toxins (UTs), are associated with increased mortality in patients with chronic kidney disease (CKD). These toxins are produced by the microbiota from the diet and excreted by the kidney. The purpose of this study was to analyze the effect of diet on IS and PCS concentration in hemodialysis (HD) patients. Methods: We performed a prospective monocentric study using a seven-day diet record and determination of serum IS and PCS levels in HD patients. We tested the association between toxin concentrations and nutritional data. Results: A total of 58/75 patients (77%) completed the diet record. Mean caloric intake was 22 ± 9.2 kcal/kg/day. The protein/fiber index was 4.9 ± 1.8. No correlation between IS or PCS concentration and protein/fiber index was highlighted. In the 18 anuric patients (31%) in whom residual renal function could not affect toxin concentrations, IS and PCS concentrations were negatively correlated with fiber intake and positively correlated with the protein/fiber index. In a multivariate analysis, IS serum concentration was positively associated with the protein/fiber index (p = 0.03). Conclusions: A low protein/fiber index is associated with low concentrations of uremic toxins in anuric HD patients. Diets with an increased fiber intake must be tested to determine whether they reduce PCS and IS serum concentrations.

Nonlinear Phototaxis and Instabilities in Suspensions of Light-Seeking Algae

The mechanism by which living organisms seek optimal light conditions-phototaxis-is a fundamental process for motile photosynthetic microbes. It is involved in a broad array of natural processes and applications from bloom formation to the production of high-value chemicals in photobioreactors. Here, we show that a population of the model alga Chlamydomonas reinhardtii exhibits a highly sensitive nonlinear response to light and demonstrate that the self-organization of cells in a heterogeneous environment becomes unstable as the result of a coupling between bioconvective flows and phototaxis.

FC034: Genomic Approach of the Undetermined Kidney Disease

BACKGROUND AND AIMS

Chronic kidney disease (CKD) is considered as a public health problem. Almost 20%–25% of patients with end-stage kidney disease have been reported with an undetermined kidney disease (UKD) in large national registry. Recent data have shown that the number of monogenic disease-causing variants among patients with CKD is about 20%–30%. Monogenic disease-causing variants are underdiagnosed. We performed whole exome sequencing on patients in our centre with UKD.

METHOD

All patients gave their written informed consent for genetic testing. Whole exome sequencing by next-generation sequencing was proposed in routine care practice to patient with UKD between January 2019 and December 2021. High and reproducible coverage achieved by our sequencing approach enabled copy-number variation (CNV) analysis. All patients with inconclusive biopsy results were included. Only one patient from the same pedigree was included. We excluded patients with a typical presentation of ADPKD, familial IgA nephropathy, patients with typical presentation of Gitelman or Bartter syndrome or established genetic diagnosis in the family.

RESULTS

A total of 211 adult patients were included (120 males) with a median age of 48 years (range 37–62 years). Of these, 50 patients were treated with haemodialysis, 34 patients had a kidney transplantation. A total of 156 had self-declared Caucasian. Consanguinity was reported by 12 patients and suspected in 11 patients. Family history of kidney disease was present in 108 patients with both first and second degree affected in 38 patients. Kidney biopsy were inconclusive in 62 patients. Kidney biopsy was impossible in 57 incidents patients with CKD during the study period. A WES was performed first to avoid kidney biopsy in nine patients. A negative genetic testing prior to the WES with gene panel has been performed in 31 patients. We detected 27 monogenic renal disorders in 73 patients with either pathogenic or likely pathogenic variants and 5 copy number variants among 211 patients (37%). The glomerular disease represent the first yielded diagnostic subgroup in which Alport diseases (COL4A3/4/5) represent the dominant diagnostic (COL4A4 n = 18; COL4A3 n = 12; COL4A5 n = 7; TTC21B n = 3; APOL1 = 2; INF2 n = 2; PAX2 n = 2; TRPC6 n = 2; TREX1 n = 1; COQ8B n = 1; NPHS1 n = 1). Tubulointerstitial diseases is the second yielded diagnostic subgroup (UMOD n = 7; NPHP1 n = 2; NPHP3 n = 1; CCL5 n = 1; HNF1B n = 1; CNM4 n = 1; KCNJ1 n = 1). Cystic disease and CAKUT is the third yielded diagnostic subgroup (PKHD1 n = 3; DNAJB11 n = 2; VHL n = 1; PKD1 n = 1; GREB1L n = 1; PBX1 n = 1). In addition, we find two patients with pathogenic complement variation (CFH et C3), one patient with TTR amyloidosis and one patient with familial renal glucosuria (SLC5A2). Six of the nine patients with WES first to avoid renal biopsy, have positive diagnostic (five Alport disease and one APOL1 nephropathy). Interestingly, one of these nine patients had a WES for nephrotic syndrome during type-I diabetes and a dialysis sister with undetermined glomerular disease and consanguineous parents, which detected a known variation in TTC21B gene (P209L) at a heterozygote state that did not explain the nephrotic syndrome. We performed Sanger sequencing for her sister and revealed the same variation at a homozygous state and explain her renal phenotype. Among 57 patients with impossible kidney biopsy, the WES was positive for 18 patients. The diagnostic yield of WES was higher in consanguineous patients (P = 0.04) and familial history of kidney disease (P &lt; 0.0001). The diagnostic yielded reach 60.5% when the patient had family history of renal disease in both first and second degree of the pedigree.

CONCLUSION

WES identified a molecular diagnosis in almost 40% of patients with UKD in our centre. An exome first may have a high diagnostic yielded and avoid an invasive procedure like kidney biopsy or when it is impossible. WES must be included as a standard of care for patients with UKD.

Two-Level Optimization to Reduce Waiting Time at Locks in Inland Waterway Transportation

Inland vessels often have to cross numerous locks before reaching their final destination, which leads to a significant delay and sometimes represents as much as half of the total travel time. The delay affects shipment costs and can affect other parts of the transport chain, adversely impacting this transportation mode’s growth. Therefore, this work presents a two-level solution to ensure a shorter waiting time at locks and improve inland waterway transport. On the one hand, the first level focuses on making infrastructural modifications by proposing an efficient Lock Automation Decision Making (Lock-ADM) method. The problem modeling consists of using a three-stage algorithm. Firstly, we calculate the optimal number of locks while minimizing the investment costs using the exact solver, CPLEX. Secondly, we measure the importance of locks in the network, and finally, we select the best locks to automate using the Genetic Algorithm (GA) metaheuristic. Based on real data, we achieved an average reduction of 33.7 % in overall lock waiting time at a low cost. On the other hand, the second level proposes a Dynamic Lock Scheduling (Lock-DS) to efficiently manage vessels scheduling at locks by minimizing their waiting time and optimizing their speed. We achieve an average reduction of 69.9 % in vessel waiting time and a reduction of 48.03 % in total fuel consumption compared to existing scheduling methods. Automating the most important locks with Lock-ADM and managing their crossing with Lock-DS ensure shorter vessels’ waiting time and represent a significant first step towards the automation of inland navigation.

Successful treatment with adapted high dose methotrexate in a hemodialysis patient with primary central nervous system lymphoma: 100mg/m2 seems sufficient

High dose methotrexate (HD-MTX) based chemoimmunotherapy is a central part of the standard approach to treatment of primary central nervous system lymphoma (PCNSL). Renal dysfunction leads to delayed MTX complete elimination and critical MTX concentration. Despite the recommendations, hemodialysis status should not exclude HD-MTX. We report the case of a 64 years old woman on chronic hemodialysis with PCNSL successfully treated with HD-MTX-based chemoimmunotherapy with an adjusted dose of 100mg/m², instead of the usual dose of 3500mg/m², and daily hemodialysis started 24h later. The patient had no significant toxicity and was in complete remission at 1 year after the end of the treatment. We argue that ESRD is not an absolute pitfall to the use of HD-MTX for hematological malignancies. Experts should consider the use of adjusted dose at 100mg/m² as a viable therapeutic modality in ESRD patients.

Rheopheresis for severe peripheral arterial disease in hemodialysis patients: A clinical series

BACKGROUND

Rheopheresis is a double-filtration plasmapheresis that removes high-molecular-weight molecules from the plasma and thereby lowers blood viscosity. This treatment has been proposed in hemodialysis (HD) patients for chronic limb-threatening ischemia (CLTI), but very few studies have evaluated the usefulness of this technique.

PRINCIPAL OBJECTIVE

To assess 1-year amputation-free survival (AFS) of HD patients suffering from CLTI treated by rheopheresis.

MATERIAL AND METHOD

We conducted a retrospective study of 28 consecutive HD patients treated by rheopheresis in three French dialysis centers between 1 February 2017 and 30 April 2019 in two indications resulting from CLTI, namely chronic ulceration or recent minor amputation with delayed healing.

RESULTS

One-year AFS rate reached 53.6 (-19.8; +16.3)%. One-year overall survival rate reached 67.9 (-20.5; +13.1)%. Main causes of death were infections and related to palliative care implying reduction or withdrawal of regular dialysis treatment. Hypotension episodes were the main rheopheresis adverse events with a prevalence rate of 13.5%. Rheopheresis sessions significantly reduced fibrinogen, C-reactive protein, α2-macroglobulin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, IgM, and estimated plasma viscosity (P < .0001).

CONCLUSION

Rheopheresis may improve clinical outcomes of CLTI in HD patients. The assessment of rheopheresis effectiveness needs to be confirmed by a multicenter randomized controlled trial, such as the ongoing project in France (RHEO-PAD, NCT: 03975946).

[Evaluation of ambulance transport relevance of dialysis patients in the PACA region (France), and estimation of savings by the Health Insurance]

INTRODUCTION

Patient transport represents the second largest item of cost of dialysis after hospitalization. A significant proportion of patients transported by ambulance are self-sufficient for walking.

DESCRIPTION

A study was carried out in the PACA region (France) to analyse the profile of patients transported by ambulance and self-sufficient for walking and then to evaluate the savings for the Health Insurance.

METHODS

A triangulation of data was carried out using data from haemodialysis patients recorded in the French REIN Registry in 2017 and data from two surveys: one of a sample of patients transported by ambulance and autonomous in walking, and the other of 62 nephrologists.

RESULTS

The data from the REIN register allowed us to estimate that 44 % of patients transported by ambulance are self-sufficient for walking. Our study allowed us to estimate that 2/3 of patients transported by ambulance, self-sufficient for walking, have a reason for being transported by ambulance; for the third without a reason, the health insurance savings would amount to €2 million per year with a reclassification of their transport as seated transport. The survey of prescribers showed that there are exemptions justified by a temporary deterioration in health and/or housing conditions, but also by the lack of seated transport.

CONCLUSION

One third of the patients, transported by ambulance and self-sufficient for walking, would have an inappropriate transport. This would be explained by the fluctuating state of health of the patients and would also linked to the lack of seated transportation. Savings are possible and depend in part on improved management of the supply.

Kidney biopsy in very elderly patients: indications, therapeutic impact and complications

BACKGROUND

Few data is available on the risk/benefit balance of native kidney biopsy (KB) in very elderly patients.

METHODS

Multicenter retrospective cohort study in the Aix-Marseille area: the results of KB and medical charts of all patients over 85 years biopsied between January 2010 and December 2018 were reviewed.

RESULTS

104 patients were included. Median age was 87 years. Indications for KB were: acute kidney injury (AKI) in 69.2% of patients, nephrotic syndrome (NS) with AKI in 13.5%, NS without AKI in 12.5%, and proteinuria in 4.8%. Median serum creatinine was 262 μmol/L, 21% of patients required dialysis at the time of KB. Significant bleeding occurred in 7 (6.7%) patients, requiring blood cell transfusion in 4 (3.8%), and radiological embolization in 1 (1%). The most frequent pathological diagnoses were: non-diabetic glomerular diseases (29.8%, including pauci-immune crescentic glomerulonephritis in 9.6%), hypertensive nephropathy (27.9%), acute interstitial nephritis (16.3%), renal involvement of hematological malignancy (8.7%), and acute tubular necrosis (6.7%). After KB, 51 (49%) patients received a specific treatment: corticosteroids (41.3%), cyclophosphamide (6.7%), rituximab (6.7%), bortezomib (3.8%), other chemotherapies (3.8%). Median overall survival was 31 months.

CONCLUSIONS

KB can reveal a diagnosis with therapeutic impact even in very elderly patients. Severe bleeding was not frequent in this cohort, but KB may have not been performed in more vulnerable patients.

Disease Activity and Adverse Events in Patients with ANCA-Associated Vasculitides Undergoing Long-Term Dialysis

BACKGROUND AND OBJECTIVES

Kidney impairment of ANCA-associated vasculitides can lead to kidney failure. Patients with kidney failure may suffer from vasculitis relapses but are also at high risk of infections and cardiovascular events, which questions the maintenance of immunosuppressive therapy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with ANCA-associated vasculitides initiating long-term dialysis between 2008 and 2012 in France registered in the national Renal Epidemiology and Information Network registry and paired with the National Health System database were included. We analyzed the proportion of patients in remission off immunosuppression over time and overall and event-free survival on dialysis (considering transplantation as a competing risk). We compared the incidence of vasculitis relapses, serious infections, cardiovascular events, and cancers before and after dialysis initiation.

RESULTS

In total, 229 patients were included: 142 with granulomatous polyangiitis and 87 with microscopic polyangiitis. Mean follow-up after dialysis initiation was 4.6±2.7 years; 82 patients received a kidney transplant. The proportion of patients in remission off immunosuppression increased from 23% at dialysis initiation to 62% after 5 years. Overall survival rates on dialysis were 86%, 69%, and 62% at 1, 3, and 5 years, respectively. Main causes of death were infections (35%) and cardiovascular events (26%) but not vasculitis flares (6%). The incidence of vasculitis relapses decreased from 57 to seven episodes per 100 person-years before and after dialysis initiation (P=0.05). Overall, during follow-up, 45% of patients experienced a serious infection and 45% had a cardiovascular event, whereas 13% experienced a vasculitis relapse.

CONCLUSIONS

The proportion of patients with ANCA-associated vasculitis in remission off immunosuppression increases with time spent on dialysis. In this cohort, patients were far less likely to relapse from their vasculitis than to display serious infectious or cardiovascular events.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_11_08_CJN03190321.mp3.

Effect of age and care organization on sources of variation in kidney transplant waiting list registration

Despite national guidelines, medical practices and kidney transplant waiting list registration policies may differ from one dialysis/transplant unit to another. Benefit risk assessment variations, especially for elderly patients, have also been described. The aim of this study was to identify sources of variation in early kidney transplant waiting list registration in France. Among 16 842 incident patients during the period 2016-2017, 4386 were registered on the kidney transplant waiting list at the start of, or during the first year after starting, dialysis (26%). We developed various log-linear mixed effect regression models on three levels: patients, dialysis networks, and transplant centers. Variability was expressed as variance from the random intercepts (± standard error). Although patient characteristics have an important impact on the likelihood of registration, the overall magnitude of variability in registration was low and shared by dialysis networks and transplant centers. Between-transplant center variability (0.23 ± 0.08) was 1.8 higher than between-dialysis network variability (0.13 ± 0.004). Older age was associated with a lower probability of registration and greater variability between networks (0.04, 0.20, & 0.93 in the 18-64, 65-74, and 75-84 age groups). Targeted interventions should focus on elderly patients and/or certain regions with greater variability in waiting list access.

Impact of insulin adsorption in various containers during hyperkalaemia treatment

Background

Insulin–glucose therapy in hyperkalaemia treatment has a narrow therapeutic index for a safe and efficient use. We assess the variability of the effective delivered insulin under conditions used in the setting of hyperkalaemia treatment.

Methods

A range of simulated insulin infusions was studied using different containers (bag or syringes) according to the different hyperkalaemia treatment procedures of our institution. Insulin concentration was assayed using a chromatographic method on an automatic high-performance liquid chromatography. We calculated the effective delivered insulin and compared the time average of percentage delivered insulin (TAdi) between all the procedures.

Results

The TAdi was significantly decreased to 63.3% of the expected insulin delivery in the polyurethane (PE) bag compared with allover container. The procedure duration and the insulin concentration influenced the variability of the insulin delivery in the PE and glass bag. The polyvinyl chloride bag had the highest TAdi at 93.8%, without significant variation during the time. TAdi reaches ∼90% of the expected insulin with all the syringe procedure without variation according to the solute used to dilute insulin.

Conclusions

Clinically significant variations in intravenous insulin delivery occur in the setting of hyperkalaemia treatment according to the container. The use of propylene syringe limits the insulin delivery variation. In the future, clinical studies on hyperkalaemia treatment by insulin–glucose therapy should detail the procedure precisely.

Spike and neutralizing antibodies response to COVID-19 vaccination in haemodialysis patients

Background

Humoral response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines needs to be evaluated in the fragile population of patients on maintenance haemodialysis (HD).

Methods

We analysed the antibody response to the spike (S) antigen of SARS-CoV-2 before and after each dose of the messenger RNA (mRNA) Comirnaty vaccine (BNT162b2; BioNTech & Pfizer) in patients from a single dialysis centre and detected the presence of neutralizing antibodies (Nabs).

Results

Among the 90 vaccinated HD patients (mean age 69 years, 61% male), 19 (21%) had a history of SARS-CoV-2 infection. A seroconversion with anti-S immunoglobulin G antibodies (Sabs) was documented in 20% of patients after the first dose (early responders) and in 77% after the second dose, while 23% were non-responders. Cardiac disease, cirrhosis and gamma globulin levels were independently predictive of the absence of seroconversion. Nabs were detected in 15.4% of early responders after the first dose and in 84.6% of early responders and 57.9% of late responders after the second dose. Sab titres after the second dose were higher in patients with Nab than without Nab {598 [interquartile range (IQR) 246–882]) versus 134 [IQR 61–390]; P < 0.0001}. All patients with a history of SARS-CoV-2 infection developed both Sabs and Nabs and their titres for Sabs and Nabs were higher than in late responders.

Conclusions

Most HD patients develop a substantial humoral response against SARS-CoV2, with Nabs, following the mRNA vaccine. Whether this immunity persists over time and is able to efficiently protect patients from coronavirus disease 2019 remains to be determined.

Étude SeroCOVIDial : évaluation de la séroprévalence SARS-CoV2 chez les patients hémodialysés chroniques et leurs soignants après la 1re vague et avant la campagne vaccinale, une étude de cohorte

Introduction

Les patients hémodialysés chroniques (HD) constituent une population à haut risque de COVID-19 sévère, et ne peuvent rester confinés. La prévalence de l’immunisation contre le SARS-CoV-2 parmi les patients HD et les soignants, après la première vague de COVID-19 et avant la campagne de vaccination, reste inconnue.

Description

PHRC inter-régional, étude de cohorte prospective réalisée entre juin et décembre 2020 dans 4 grands centres de dialyse d’Aix–Marseille (dépistage systématique des symptômes et mesures d’isolement des malades infectés dès le début de la pandémie).

Méthodes

Séroprévalence SARS-CoV2 évaluée par test sérologique rapide (Biosynex®) chez les patients et leurs soignants en juin (M0), septembre(M3) et décembre (M6) 2020.

Résultats

En juin 2020, 451 patients HD et 238 soignants ont été inclus. La séroprévalence SARS-CoV2 à M0 était de 8,4 % chez les patients et 6,7 % chez les soignants. Parmi les participants immunisés, 26,3 % des patients et 6,3 % des soignants n’avaient présenté aucun symptôme de COVID-19. Parmi les participants ayant eu une infection SARS-CoV2 documentée avant M0, 87 % des patients et 90 % des soignants étaient immunisés à M0. La séroprévalence est restée stable à M3, et a augmenté à M6 lors de la 2^e vague épidémique, atteignant 13,8 % des patients et 12,6 % des soignants. À M6, 38 (8,4 %) patients étaient décédés dont 9 (2 %) de COVID-19, et 12 autres ont été hospitalisés pour COVID-19. Deux patients immunisés à M0 ont présenté une COVID-19 non sévère au cours du suivi.

Conclusion

Dans cette large cohorte de patients HD et de soignants, la prévalence de l’immunisation SARS-CoV2 après la première vague épidémique était relativement faible, ce qui reflète probablement l’efficacité des mesures de protection mises en place. L’immunisation n’était pas toujours persistante chez les participants, et certains patients immunisés à M0 ont pu être infectés, ce qui souligne l’intérêt de la vaccination systématique de cette population.

Successful treatment with adapted high dose methotrexate in a hemodialysis patient with primary central nervous system lymphoma: 100mg/m2 seems sufficient

High dose methotrexate (HD-MTX) based chemoimmunotherapy is a central part of the standard approach to treatment of primary central nervous system lymphoma (PCNSL). Renal dysfunction leads to delayed MTX complete elimination and critical MTX concentration. Despite the recommendations, hemodialysis status should not exclude HD-MTX. We report the case of a 64 years old woman on chronic hemodialysis with PCNSL successfully treated with HD-MTX-based chemoimmunotherapy with an adjusted dose of 100mg/m2, instead of the usual dose of 3500mg/m2, and daily hemodialysis started 24h later. The patient had no significant toxicity and was in complete remission at 1 year after the end of the treatment. We argue that ESRD is not an absolute pitfall to the use of HD-MTX for hematological malignancies. Experts should consider the use of adjusted dose at 100mg/m2 as a viable therapeutic modality in ESRD patients.

The creation and implementation of advanced practice nursing in France: Experiences from the field

AIM

This paper describes the characteristics of the new advanced practice nursing roles in France, as well as their challenges and perspectives, and compares the French model with the recommendations of the International Council of Nurses.

BACKGROUND

Advanced practice nursing is particularly well established in English-speaking countries. Since 2018, France has become the second French-speaking region to legalize and regulate advanced practice nurses.

SOURCE OF EVIDENCE

The International Council of Nurses and French government websites, and scientific databases (PubMed, CINALH, Cochrane Library) were explored. Feedback from French nursing academics was also requested.

DISCUSSION

The advanced practice nursing model in France is described according to the scope and conditions of professional practice. The educational program leads to a State diploma with master's degree, which it is mandatory to be a registered nurse. Remuneration depends on the sector of practice in the public hospital, primary care or private sector. Although there is no national strategy for the implementation of advanced practice nursing roles, research projects are being initiated to guide and evaluate the practice. Based on concordance analysis with the recommendations of the International Council of Nurses, the French advanced practice nursing model appears to be similar to the nurse practitioner model.

CONCLUSION

Adjustments in the scope of practice and education can be expected as the implementation of these roles is evaluated.

IMPLICATIONS FOR NURSING PRACTICE

This is a historical evolution of the nursing profession in France, for which communication with patients and healthcare professionals is essential.

IMPLICATIONS FOR NURSING POLICY

The implementation of advanced practice nursing roles in clinical settings requires the development of national strategies to support initiatives and ensure the sustainability of these roles.

Adverse gastrointestinal events with sodium polystyrene sulphonate and calcium polystyrene sulphonate use in dialysis patients: a nationwide registry study

INTRODUCTION

Sodium polystyrene sulphonate (SPS) and calcium polystyrene sulphonate (CPS) are commonly used cation-exchange resins for the treatment and control of hyperkalaemia. However, their use (particularly SPS) has been limited by reports of adverse gastrointestinal (GI) events. The safety of these compounds in patients undergoing dialysis requires larger investigation.

AIMS

To study the occurrence of adverse GI events (occlusion, perforation, thrombosis/ischaemia) in the periods of SPS or CPS exposition versus the periods without exposition in dialysis patients.

METHODS

Dialysis patients were extracted from the French National Registry and merged with the French hospital discharge database (between 2006 and 2017). For our primary analysis, we used patients who had any claim of SPS use (n = 43 771). Time-varying Cox models, negative binomial regression and pre- versus post-treatment average treatment effects.

RESULTS

The mean age was 66 ± 15 years, 37% were female and 92% were undergoing haemodialysis. Over a 1-year follow-up, patients on periods with SPS (on-SPS) did not present an increased risk of adverse GI events versus the periods without SPS (off-SPS):  incidence rate (IR) (per 1000 person years) = 7.4 (6.4-8.7) versus 9.5 (8.1-11.0); adjusted hazard ratio (HR) (95% CI) = 0.81 (0.60-1.09), P = 0.17. Patients exposed to SPS did not experience a higher rate of adverse GI events in the year after SPS initiation versus the year before SPS initiation; P-value for parallel trend = 0.87. Patients on-CPS also did not show an increased risk of adverse GI events versus off-CPS: IR (per 1000 py) = 8.6 (5.1-11.9) versus 7.8 (5.1-11.9); adjusted HR (95% CI) = 0.76 (0.31-1.80), P = 0.52. The rates of adverse GI events in the periods on and off exposure were also similar over a follow-up of 5 years.

CONCLUSION

Our large, nationwide study shows that the incidence of adverse GI events in patients undergoing dialysis was low and that neither the use of SPS nor CPS was associated with increased GI events risk.

Renal SPECT/CT with 99mTc-dimercaptosuccinic acid is a non-invasive predictive marker for the development of interstitial fibrosis in a rat model of renal insufficiency

BACKGROUND

Chronic kidney disease (CKD) increases cardiovascular risk and mortality. Renal fibrosis plays a major role in the progression of CKD but, to date, histology remains the gold standard to assess fibrosis. Non-invasive techniques are needed to assess renal parenchymal impairment and to perform the longitudinal evaluation of renal structure. Thus we evaluated renal isotopic imaging by single-photon emission computed tomography/computed tomography (SPECT/CT) with technetium-99m (99mTc)-dimercaptosuccinic acid (DMSA) to monitor renal impairment during renal insufficiency in rats.

METHODS

Renal insufficiency was induced by an adenine-rich diet (ARD) at 0.25 and 0.5% for 28 days. Renal dysfunction was evaluated by assaying biochemical markers and renal histology. Renal parenchymal impairment was assessed by SPECT/CT isotopic imaging with 99mTc-DMSA on Days 0, 7, 14, 21, 28, 35 and 49.

RESULTS

Compared with controls, ARD rats developed renal dysfunction characterized by increased serum creatinine and blood urea nitrogen, fibrosis and tubulointerstitial damage in the kidneys, with a dose-dependent effect of the adenine concentration. 99mTc-DMSA SPECT-CT imaging showed a significant decrease in renal uptake over time in 0.25 and 0.5% ARD rats compared with control rats (P = 0.011 and P = 0.0004, respectively). 99mTc-DMSA uptake on Day 28 was significantly inversely correlated with Sirius red staining evaluated on Day 49 (r = 0.89, P < 0.0001, R2 = 0.67).

CONCLUSIONS

99mTc-DMSA renal scintigraphy allows a longitudinal follow-up of risk of renal fibrosis in rats. We found that the reduction of renal parenchyma in ARD rats is inversely proportional to newly formed fibrous tissue in the kidney. Our results suggest that 99mTc-DMSA renal scintigraphy may be a useful non-invasive prognostic marker of the development of renal fibrosis in animals and should be tested in humans.

Vascular access cannulation and haemostasis: a national observational study of French practices

BACKGROUND

We report the results of an observational study of arteriovenous fistula (AVF) cannulation and haemostasis practices in France.

METHODS

The study (sponsored by Brothier Pharmaceutical Inc.) was conducted in 150 dialysis units. Data obtained from 150 supervisory nurses, 1538 nurses and 3588 patients with an AVF were analysed.

RESULTS

The nurses reported using rope-ladder, area or buttonhole cannulation techniques in 68, 26 and 6% of cases, respectively. Metal needles were used most frequently (64%), with mainly a diameter of 15 G or 16 G. The needle was introduced with the bevel up in 56% of cases. Compression applied using dressings (in particular, pure calcium alginate dressings) was the method of choice for haemostasis of the puncture sites and was assessed as being strong by most of the nurses and very strong in cases of prolonged bleeding. Most (82%) of the patients reported the use of local anaesthetic before cannulation and 23% reported an allergic skin reaction to the anaesthetic. Bleeding of the puncture sites lasted for >10 min for 48% of the patients and it reappeared between two sessions for 29% of the patients. Whereas the nurses appeared to have a good understanding of AVF, more than half of the patients did not know how to care for it, with 55% requiring more information.

CONCLUSIONS

This study underlines the lack of national consensus concerning AVF cannulation practices. It suggests that haemostasis methods of the puncture sites can be improved and it highlights the need to improve patient knowledge.

[The management of chronic kidney disease in France in 2021]

Chronic kidney disease affects approximately 3 million people in France. The number of patients suffering from chronic kidney failure treated by dialysis or transplantation, which stood at around 90,000 at the end of 2018, is increasing constantly. In recent years, there have been improvements in the current management of this pathology and a reform in the financing of follow-up care.

Triage of Patients Suspected of COVID-19 in Chronic Hemodialysis: Eosinophil Count Differentiates Low and High Suspicion of COVID-19

Background: Daily management to shield chronic dialysis patients from SARS-CoV-2 contamination makes patient care cumbersome. There are no screening methods to date and a molecular biology platform is essential to perform RT-PCR for SARS-CoV-2; however, accessibility remains poor. Our goal was to assess whether the tools routinely used to monitor our hemodialysis patients could represent reliable and quickly accessible diagnostic indicators to improve the management of our hemodialysis patients in this pandemic environment. Methods: In this prospective observational diagnostic study, we recruited patients from La Conception hospital. Patients were eligible for inclusion if suspected of SARS-CoV-2 infection when arriving at our center for a dialysis session between March 12th and April 24th 2020. They were included if both RT-PCR result for SARS-CoV-2 and cell blood count on the day that infection was suspected were available. We calculated the area under the curve (AUC) of the receiver operating characteristic curve. Results: 37 patients were included in the final analysis, of which 16 (43.2%) were COVID-19 positive. For the day of suspected COVID-19, total leukocytes were significantly lower in the COVID-19 positive group (4.1 vs. 7.4 G/L, p = 0.0072) and were characterized by lower neutrophils (2.7 vs. 5.1 G/L, p = 0.021) and eosinophils (0.01 vs. 0.15 G/L, p = 0.0003). Eosinophil count below 0.045 G/L identified SARS-CoV-2 infection with AUC of 0.9 [95% CI 0.81—1] (p < 0.0001), sensitivity of 82%, specificity of 86%, a positive predictive value of 82%, a negative predictive value of 86% and a likelihood ratio of 6.04. Conclusions: Eosinophil count enables rapid routine screening of symptomatic chronic hemodialysis patients suspected of being COVID-19 within a range of low or high probability.

Circulating Endothelial Cells as a Marker of Endothelial Injury in Severe COVID -19

Beside the commonly described pulmonary expression of the coronavirus disease 2019 (COVID-19), major vascular events have been reported. The objective of this study was to investigate whether increased levels of circulating endothelial cells (CEC) might be associated with severe forms of COVID-19. Ninety-nine patients with COVID-19 were enrolled in this retrospective study. Patients in the intensive care units (ICU) had significantly higher CEC counts than non-ICU patients and the extent of endothelial injury was correlated with putative markers of disease severity and inflammatory cytokines. Altogether, these data provide in vivo evidence that endothelial injury is a key feature of COVID-19.

Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

The aim of this study was to estimate the incidence of COVID-19 disease in the French national population of dialysis patients, their course of illness and to identify the risk factors associated with mortality. Our study included all patients on dialysis recorded in the French REIN Registry in April 2020. Clinical characteristics at last follow-up and the evolution of COVID-19 illness severity over time were recorded for diagnosed cases (either suspicious clinical symptoms, characteristic signs on the chest scan or a positive reverse transcription polymerase chain reaction) for SARS-CoV-2. A total of 1,621 infected patients were reported on the REIN registry from March 16th, 2020 to May 4th, 2020. Of these, 344 died. The prevalence of COVID-19 patients varied from less than 1% to 10% between regions. The probability of being a case was higher in males, patients with diabetes, those in need of assistance for transfer or treated at a self-care unit. Dialysis at home was associated with a lower probability of being infected as was being a smoker, a former smoker, having an active malignancy, or peripheral vascular disease. Mortality in diagnosed cases (21%) was associated with the same causes as in the general population. Higher age, hypoalbuminemia and the presence of an ischemic heart disease were statistically independently associated with a higher risk of death. Being treated at a selfcare unit was associated with a lower risk. Thus, our study showed a relatively low frequency of COVID-19 among dialysis patients contrary to what might have been assumed.

Unveiling of the mechanisms of acoustic streaming induced by sharp edges

Acoustic waves can generate steady streaming within a fluid owing to the generation of viscous boundary layers near walls of typical thickness δ. In microchannels, the acoustic wavelength λ is adjusted to twice the channel width w to ensure a resonance condition, which implies the use of MHz transducers. Recently, though, intense acoustic streaming was generated by acoustic waves of a few kHz (hence with λ≫w), owing to the presence of sharp-tipped structures of curvature radius at the tip r_{c} smaller than δ. The present study quantitatively investigates this sharp-edge acoustic streaming via the direct resolution of the full Navier-Stokes equation using the finite element method. The influence of δ,r_{c}, and viscosity ν on the acoustic streaming performance is quantified. Our results suggest choices of operating conditions and geometrical parameters, in particular the dimensionless tip radius of curvature r_{c}/δ and the liquid viscosity.

Risk factors for severity of COVID-19 in chronic dialysis patients from a multicentre French cohort

BACKGROUND

Coronavirus disease 2019 (COVID-19) is an emerging infectious disease, related to severe acute respiratory syndrome coronavirus 2 infection. Few data are available in patients with end-stage renal disease (ESRD).

METHODS

We conducted an observational cohort study of COVID-19 patients at 11 dialysis centres in two distinct districts of France to examine the epidemiological and clinical characteristics of COVID-19 in this population, and to determine risk factors of disease severity (defined as a composite outcome including intensive care unit admission or death) and mortality.

RESULTS

Among the 2336 patients enrolled, 5.5% had confirmed COVID-19 diagnosis. Of the 122 patients with a follow-up superior to 28 days, 37% reached the composite outcome and 28% died. Multivariate analysis showed that oxygen therapy on diagnosis and a decrease in lymphocyte count were independent risk factors associated with disease severity and with mortality. Chronic use of angiotensin II receptor blockers (ARBs) (18% of patients) was associated with a protective effect on mortality. Treatment with azithromycin and hydroxychloroquine (AZT/HCQ) (46% of patients) were not associated with the composite outcome and with death in univariate and multivariate analyses.

CONCLUSIONS

COVID-19 is a severe disease with poor prognosis in patients with ESRD. Usual treatment with ARBs seems to be protective of critical evolution and mortality. There is no evidence of clinical benefit with the combination of AZT/HCQ.

Acute kidney injury in patients treated with anti-programmed death receptor-1 for advanced melanoma: a real-life study in a single-centre cohort

BACKGROUND

Immune checkpoints inhibitors have transformed the prognosis of advanced melanoma but are associated with immune-related adverse events (irAEs). We evaluated the incidence, risk factors and causes of acute kidney injury (AKI) in a monocentric real-life cohort of patients treated with anti-programmed death receptor-1 (anti-PD1) antibodies for advanced melanoma.

METHODS

Retrospective collection of medical charts and comprehensive analysis of lab results from patients treated with nivolumab or pembrolizumab for advanced melanoma between 2014 and 2018 was carried out. AKI was defined by Kidney Disease Improving Global Outcomes criteria, and causes were determined by chart review. Overall survival, survival without AKI and impact of AKI on survival were analysed. Risk factors for death and for AKI were identified.

RESULTS

Two hundred and thirty-nine patients were included. Forty-one (17%) had at least one episode of AKI. Independent risk factors for AKI were treatment with renin-angiotensin-aldosterone system inhibitors (RAASi), pre-existing chronic kidney disease (CKD) and cumulated doses of anti-PD1. The main cause of AKI was prerenal, and only eight patients (3.3%) developed acute interstitial nephritis; 8% of patients developed CKD. The median overall survival was 13.4 months and was not affected by AKI. In multivariate analysis, the overall mortality was lower in overweight and obese patients and higher in patients treated with proton-pump inhibitors (PPI) or corticosteroids.

CONCLUSIONS

AKI is common in patients treated with anti-PD1 for advanced melanoma but is mostly prerenal and favoured by the use of RAASi; renal irAE is rare. PPI and corticosteroids were associated with poor survival in this population, while overweight/obesity was protective.

Acoustic Streaming Generated by Sharp Edges: The Coupled Influences of Liquid Viscosity and Acoustic Frequency

Acoustic streaming can be generated around sharp structures, even when the acoustic wavelength is much larger than the vessel size. This sharp-edge streaming can be relatively intense, owing to the strongly focused inertial effect experienced by the acoustic flow near the tip. We conducted experiments with particle image velocimetry to quantify this streaming flow through the influence of liquid viscosity ν , from 1 mm 2 /s to 30 mm 2 /s, and acoustic frequency f from 500 Hz to 3500 Hz. Both quantities supposedly influence the thickness of the viscous boundary layer δ = ν π f 1 / 2 . For all situations, the streaming flow appears as a main central jet from the tip, generating two lateral vortices beside the tip and outside the boundary layer. As a characteristic streaming velocity, the maximal velocity is located at a distance of δ from the tip, and it increases as the square of the acoustic velocity. We then provide empirical scaling laws to quantify the influence of ν and f on the streaming velocity. Globally, the streaming velocity is dramatically weakened by a higher viscosity, whereas the flow pattern and the disturbance distance remain similar regardless of viscosity. Besides viscosity, the frequency also strongly influences the maximal streaming velocity.

Uremic Toxic Blood-Brain Barrier Disruption Mediated by AhR Activation Leads to Cognitive Impairment during Experimental Renal Dysfunction

BACKGROUND

Uremic toxicity may play a role in the elevated risk of developing cognitive impairment found among patients with CKD. Some uremic toxins, like indoxyl sulfate, are agonists of the transcription factor aryl hydrocarbon receptor (AhR), which is widely expressed in the central nervous system and which we previously identified as the receptor of indoxyl sulfate in endothelial cells.

METHODS

To characterize involvement of uremic toxins in cerebral and neurobehavioral abnormalities in three rat models of CKD, we induced CKD in rats by an adenine-rich diet or by 5/6 nephrectomy; we also used AhR^-/- knockout mice overloaded with indoxyl sulfate in drinking water. We assessed neurologic deficits by neurobehavioral tests and blood-brain barrier disruption by SPECT/CT imaging after injection of ^99mTc-DTPA, an imaging marker of blood-brain barrier permeability.

RESULTS

In CKD rats, we found cognitive impairment in the novel object recognition test, the object location task, and social memory tests and an increase of blood-brain barrier permeability associated with renal dysfunction. We found a significant correlation between ^99mTc-DTPA content in brain and both the discrimination index in the novel object recognition test and indoxyl sulfate concentrations in serum. When we added indoxyl sulfate to the drinking water of rats fed an adenine-rich diet, we found an increase in indoxyl sulfate concentrations in serum associated with a stronger impairment in cognition and a higher permeability of the blood-brain barrier. In addition, non-CKD AhR^-/- knockout mice were protected against indoxyl sulfate-induced blood-brain barrier disruption and cognitive impairment.

CONCLUSIONS

AhR activation by indoxyl sulfate, a uremic toxin, leads to blood-brain barrier disruption associated with cognitive impairment in animal models of CKD.

Experimental study of the POP technique: focus on the physical basis of the process

INTRODUCTION

Central or peripheral vascular access devices have been in use for many decades. However, despite adequate care and maintenance, complete occlusion may occur, and its impact cannot be overlooked. A new procedure using a percussion technique has been published and referred as 'the POP technique'.

METHODS

A hydrodynamic bench was used permitting both the recording of the movement of the piston with a fast camera and the pressure variations in the polyurethane and silicone catheters while connected to 2- and 3-piece syringes.

RESULTS

The results are twofold. First the upward movement of the piston leads to the installation of a saturation vapour pressure in the body of the syringe. During this sequence, the clot is submitted to a force of aspiration. Then the release of the plunger leads to a pulse pressure whose dynamics and intensity are dependent of the types of syringes and catheters.

CONCLUSIONS

The experiments bring to light the importance of practical features such as the orientation of the syringe and the nature of the polyurethane or silicone catheters. Then the analysis enables the definition of practical rules for safe practice of the POP technique. This study will impact clinicians as many may be tempted to use the technique in hope to resolve the occlusion safely, in a timely manner.

Spatiotemporal trends and prognosis of end-stage renal disease patients with biopsy-proven immunoglobulin A nephropathy in France from 2010 to 2014

Background

Although end-stage renal disease (ESRD) is frequently used as an outcome marker for primary immunoglobulin A nephropathy (IgAN), the clinical course after reaching ESRD is not well documented. This study examined patients’ characteristics and survival in ESRD-related biopsy-proven IgAN in France.

Methods

French Renal Epidemiology and Information Network Registry data from 2010 to 2014 were used to analyse patients’ survival and outcome in incident ESRD patients >16 years of age with biopsy-proven primary IgAN, in comparison with other primary and secondary glomerulonephritis (GN), adult polycystic kidney disease (ADPKD) or diabetes. Multivariable survival analysis was adjusted for age, sex, time on dialysis and comorbidities.

Results

Among 17 138 incident dialysis patients with ESRD, IgAN (242.8/10 000 dialysis initiation) represents the most common GN related to ESRD during 2010. IgAN patients were the youngest, and had the fewest comorbidities and the highest use of peritoneal dialysis (PD) (17%). In comparison with the haemodialysis group, hazard ratios for death were not different in the preemptive transplantation group [0.46, 95% confidence interval (CI) 0.17–1.28] and in the PD group (0.77, 95% CI 0.44–1.33). Mortality rates in IgAN patients with preemptive transplantation and in those receiving dialysis waiting for transplantation were 2.9% (95% CI 0.0–5.6) and 6.7% (95% CI 0.9–12.3). Mortality rates of ADPKD patients receiving dialysis waiting for transplantation were higher (18%, 95% CI 3.1–30.6).

Conclusion

IgAN has the best prognosis among primary and secondary GN. IgAN patients receiving dialysis waiting transplantation seem to have a more favourable prognosis than ADPKD patients, who usually comprise the reference population. The underlying reasons for the difference in access treatment modalities should be investigated to improve survival with respect to renal disease.