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.

Presence of specific SARS-COV2 antibodies in hemodialysis patients and their caregivers after the first wave of COVID-19.

Hemodialysis (HD) patients are at risk for severe COVID-19 and cannot comply with social distancing. SARS-COV2 seroprevalence in French patients and caregivers after the first wave of COVID-19 is unknown. SeroCOVIDial is a prospective study conducted between June and December 2020. SARS-COV2 seroprevalence was evaluated by a rapid serological test (BIOSYNEX) in HD patients and caregivers, and the presence or not of anti-SARS-COV2 neutralizing or non-neutralizing antibodies in patients was also determined by ELISA and seroneutralization. In June 2020, 451 HD patients and 238 caregivers were included. Overall SARS-COV2 seroprevalence was 8.4% (patients) and 6.7% (caregivers), and was 87.1% (patients) and 90.0% (caregivers) in participants with a previously documented SARS-COV2 infection. Overall seroprevalence reached 13.8% (patients) and 12.6% (caregivers) following the second epidemic wave. During the follow-up, 38 (8.4%) patients died (9 of COVID-19). Among the 44 (10.6%) patients who became infected, only two were seropositive at M0. The levels of anti-SARS-COV2 antibodies decreased over time in patients and caregivers. The BIOSYNEX test showed 82.9% sensitivity and 97.7% specificity. Prevalence of anti-SARS-COV2 antibodies was low in HD patients and caregivers after the first epidemic wave but rose after the second wave. A rapid serological test showed good performances and could be useful for future monitoring of anti-SARS-COV2 antibodies.

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).

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.

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.

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.

[Experiment of self blood pressure measurement at home in haemodialysis patients in a hospital unit]. / Expérience de l'automesure tensionnelle à domicile chez des patients hémodialysés dans une unité hospitalière.

We analyzed, by home blood pressure (BP) self-measurement and conventional predialytic measurement of BP, a cohort of haemodialysis patients in two hospital units between 2008 and 2010. All patients who already own a BP self-measurement device were included in this study. BP was recorded by the two methods for one week. The number of patients with a validated self-measurement device was 69 of 350 (21%) and 60 patients were included in analyses. These patients were divided into 23 (38%) permanent uncontrolled hypertensive (elevated BP at home and in hospital), 13 (22%) masked hypertensive (normal BP in hospital and elevated at home), eight (13%) white coat hypertensive (elevated BP in hospital and normal at home), and 16 (27%) permanent controlled normotensive (normal BP in hospital and at home). Patient compliance with all the self BP measurements was 95%. We did not find in this cohort the factors associated with masked hypertension in the general population such as being male, smoking and high body mass index. These results obtained in an in-hospital dialysis unit should be extrapolated with caution to all haemodialysis patients. However it is, to our knowledge, the first study on home BP self-measurement published in patients undergoing haemodialysis in France. A significant proportion of patients have masked hypertension. This should alert clinicians because of the poor cardiovascular prognosis associated with masked hypertension.

[Hemodialysis procedure in a patient treated with radioactive iodine]. / Procédure d'hémodialyse chez un patient traité par iode 131.

The treatment of a patient with 131I at activity over 740 mega Becquerel (MBq) must be performed in a nuclear medicine department. Isolation is stopped if the patient radiation level is less than 20 muSv/hour at one meter. As regards patients with chronic renal failure treated with hemodialysis (HD), the first HD session will eliminate the major part of the radioactivity. French regulations do not give definite recommendations for this session. However, it imposes to collect liquid and solid wastes contaminated by radioactivity. Thus, it seems necessary to collect dialysate and solid wastes and to stock them in a room dedicated to radiation decay. The risk for dialysis staff is to be contaminated by an accidental ingestion of a biologic fluid from the patient. The usual protection barriers used during the HD session are sufficient: mask, gloves, overgarments, cap. There is no risk linked to external exposure to radiations. The maximal theoretical dose received by the staff during the session is 65 muSv, while annual maximal dose for public exposed to radiations is 1000 muSv. Although the dosimetric follow-up of dialysis staff is not mandatory, the nuclear medicine department of Marseille University Hospital has decided to do it in an information perspective. The session is performed in the presence of a radiation safety technician who gives film badges and active dosimeters to the dialysis staff. He reports the dialysis staff to the nuclear safety agency (Autorité de sûreté nucléaire).