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Introduction: High-flux hemodialysis membranes may modulate the cytokine storm of SARS-CoV-2, but their impact on chronic hemodialysis (CHD) patients is unknown. The aim of the study was the evaluation of asymmetric cellulose triacetate (ATA) and polymethylmethacrylate (PMMA) dialyzers on inflammatory markers and clinical outcomes in CHD patients with SARS-CoV-2. Methods: A prospective, observational study on CHD patients with SARS-CoV-2 was carried out. Patients were enrolled from March 2020 to May 2021. Pre- and postdialysis C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) were determined at each session. Patients who underwent on-line hemodiafiltration (OLHDF) with a PMMA dialyzer were compared with those treated with OLHDF with a ATA dialyzer. The primary endpoint was the differences in the reduction ratio per session (RR) of CRP, PCT, IL-6, and IL-6 RR >25%. Results: We consecutively enrolled 74 CHD patients with COVID-19, 48 were treated with ATA membrane, and 26 with PMMA. Median IL-6 RR was higher in the ATA group compared to PMMA (17.08%, IQR −9.0 to 40.0 vs. 2.95%, IQR −34.63 to 27.32). Median CRP RR was 7.77% (IQR 2.47–13.77) in the ATA group versus 4.8% (IQR −2.65 to 11.38) in the PMMA group (p = 0.0017). Median PCT-RR% was 77.38% (IQR 70.92–82.97) in ATA group versus 54.59% (IQR 42.62–63.16) in the PMMA group (p < 0.0001). A multiple logistic regression analysis with IL-6 RR >25% as the outcome including the membrane employed, pre-dialysis IL-6, CRP, PCT, and ferritin showed that ATA led to a higher probability to reach the outcome (OR 1.891, 95% CI 1.273–2.840, p = 0.0018) while higher CRP favors the risk of lower IL-6 RR values (OR 0.910, 95% CI 0.868–0.949, p ≤ 0.0001). Conclusions: In SARS-CoV-2 CHD patients treated with OLHDF, ATA showed a better anti-inflammatory profile, regarding IL-6 RR, compared to PMMA.

Chronic hemodialysis patients are at high risk of severe COVID-19 disease and death related to the infection. Anti-spike monoclonal antibodies administration reduces risk of disease progression and hospitalization in high-risk subjects but no clear data on end-stage renal disease are available. We report 2 cases of Bamlanivimab/Etesevimab administration to two not hospitalized chronic hemodialysis patients with SARS-CoV2 infection. Since they are large molecules (human immunoglobulin G1) with molecular weight of 146,000 Da, administration was conducted during the second hour of the dialysis session with no adverse reaction. Conclusions: Intradialytic administration of Bamlanivimab/Etesevimab could be considered safe and may allow adequate clinical observation time without hospital-stay prolongation.

Background/Aim: Supra hemodiafiltration with reinfusion of the endogenous ultrafiltrate (Supra-HFR) is a dialysis technique used to improve uremic toxin removal in the range of the middle molecular weight molecules. Supra-HFR does not require the preparation and online infusion of high-purity dialysis water because it allows the production of an endogenous ultrafiltrate that undergoes detoxification through an adsorbing resin. Patients and Methods: We investigated the ability of Supra-HFR to remove fibroblast growth factor 23 (FGF23), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), interleukin 8 (IL-8), and transforming growth factor alpha (TGF-alpha) after a single session dialysis in nine patients affected by end stage renal disease (ESRD). The same patients underwent a single session of online hemodiafiltration (OL-HDF) to evaluate possible differences in FGF23 and IL-6 levels. Results: A significant reduction in FGF23 was observed with both Supra-HFR (p=0.001) and OL-HDF. As for TNF-alpha and TGF-alpha, which were measured using Supra-HFR only, their percentage values were significantly lower at the end of dialysis than at the start (p=0.0028 and p=0.03, respectively). This did not change with post-dialysis rebound. Supra-HFR was found to have no effect on IL-6 and IL-8. Interestingly, the removal rate for FGF23 and IL-6 was similar to that observed with OL-HDF. Conclusion: Supra-HFR was not superior to OL-HDF, with suboptimal convective volume in the removal of the molecules tested, especially FGF23, which is considered a large middle molecular weight uremic toxin.

Hemodialysis (HD) is known to trigger a chronic inflammatory status, affecting the innate and acquired immune response. This study was aimed at a comparative analysis of immune cell subsets, proliferation, and apoptosis in subjects receiving chronic HD treatment with respect to a healthy control. Regardless of the dialysis filter used, we observed a reshaping of the acquired immune component both with respect to healthy patients and between the various sessions of dialysis treatment, with an impairment of CD3 cells, along with an increase in CD4 and CD8 cell populations producing pro-inflammatory factors such as IL-17 and IFN-gamma. The population of B cells, monocytes and NK cells were not impaired by the dialysis procedure. These results confirmed the high impact of the HD treatment on the patient’s immune system, underlying the imbalance of T cell counterparts.

BACKGROUND AND AIMS Arteriovenous fistula (AVF) must be the first choice where eligible and a prompt approach within 48–72 h should be performed in case of acute AVF failure in order to maintain the patency of the vascular access. Evaluation of the most appropriate de-clotting technique must be made considering the patient's comorbidity, AVF characteristics and absolute, relative and temporary contraindications to each kind of corrective intervention. The outcome is different between the multiple methods and nowadays mechanical thromboaspiration (MT) seems to be an innovative and promising approach. METHOD A total of 9 AVF of 9 chronic haemodialysis patients with acute AVF failure were treated with MT between January 2019 and January 2022 and were retrospectively evaluated. MT was carried out via Indigo catheter (Penumbra Inc.), an aspiration system intended for the removal of emboli and thrombi from vessels through venipuncture of AVF/AVG: the continuous aspiration helps distinguish clots from normal blood flow; in case of resistant clots, separators of many sizes can be used at the tip of the catheter to facilitate their fragmentation and aspiration. Adjunctive procedures such as balloon angioplasty (used at all sites), local fibrinolysis, heparin infusion, or stents placement were considered. Technical success was defined by clot removal from AVF or AVG. Clinical success was defined by the restoration of thrill and bruit together with AVF usability after the procedure. Vascular access survival defined as AVF/AVG usability at 3 and 6 months was assessed. RESULTS Average age was 71.2 years; dialysis vintage was 93.4 months. Medium follow-up was 13.1 months. All patients needed placement of a temporary central venous catheter (CVC) and dialysis before the MT. Technical success was achieved in 100% of the procedures, clinical success was achieved in 88.9% of the MT (despite the technical success, in 1/9 patients AVF could not be used due to a severe residual venous stenosis). None reported peri-/intraprocedural complications. In 2/9 MT there was no use of anticoagulation; in 5/9 patients, a single unfractionated heparin bolus was used (2500 UI) during the manoeuvre; in 2/9 patients, a single 2500 UI bolus plus continuous intravenous infusion of unfractionated heparin was administered combined with local thrombolysis with urokinase: both patients needed blood transfusions after the manoeuvre, one of them reporting severe haemorrhage from AVF. As adjunctive procedures, 9/9 patients underwent balloon angioplasty; one of them needed stent placement over the venous stenosis. CVC was removed less than 48 h from the procedure in 5/9 patients (55.6%), in 3/9 patients it was removed after 48 h, while 1/9 patients maintained the temporary vascular access due to the lack of clinical success after MT. Double-needle puncture occurred after a medium time of 3.5 days. AVF survival at 3 months and 6 months was 66.6% (6/9 patients), while 3/9 patients faced AVF failure (1/3 patients deceased 2 months after the procedure with a functioning AVF, in 1/3 patients a relapse of AVG thrombosis occurred 2 months after the procedure, 1/3 never reached clinical success due to severe residual venous stenosis). At the time of study design, 3/9 patients resulted to be deceased due to causes unrelated to the procedure. (1/3 due to complications of abdominal surgery, 1/3 due to sepsis, 1/3 due to subarachnoid haemorrhage). CONCLUSION MT is an innovative yet functional and safe procedure that allows declotting of the thrombosed AVF while reducing or avoiding anticoagulation and/or surgery.

BACKGROUND AND AIMS High flux haemodialysis membranes may modulate the cytokine storm of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but their impact in chronic haemodialysis (CHD) patients is not assessed [1, 2]. The aim of the study was the evaluation of asymmetric cellulose triacetate (ATA) and polymethylmethacrylate (PMMA) dialyzers on inflammatory markers in CHD patients with SARS-CoV-2. METHOD A prospective, observational study on CHD patients (age ≥18 years) affected by SARS-CoV-2 was carried out. Patients were enrolled from March 2020 to May 2021 and dialysis was performed at S. Orsola University Hospital (Bologna, Italy) Dialysis Unit. Mechanical ventilation at diagnosis was exclusion criteria. Pre- and post-dialysis C-reactive protein (CRP), procalcitonin (PCT) and interleukin-6 (IL-6) were determined at each session and corrected for haemoconcentration during the complete SARS-CoV-2 period. Patients who underwent online haemodiafiltration (OLHDF) with PMMA dialyzer (Filtryzer BG-U™, Toray, surface area 2.1 m2 cut-off 20 kDa, KUF 43 mL/h/mmHg) were compared with those who underwent OLHDF with ATA dialyzer (SolaceaTM Nipro, surface area 2.1 m2 cut-off 45 kDa, KUF 72 mL/h/mmHg). The primary endpoint was to assess the differences in the reduction ratio/session (RR) of CRP, PCT and IL-6. RESULTS A total of 74 patients were enrolled, 48 were treated with ATA and 26 were with PMMA (420 versus 191 dialysis sessions). The main results are shown in Table 1. Median IL-6RR% was higher for ATA [17.08%, interquartile range (IQR) −9.0 to 40.0 versus 2.95%, IQR −34.63 to 27.32]. CRP and PCT showed higher RR with ATA in comparison to PMMA. When IL-6RR > 25% was the dependent variable in the multiple logistic regression analysis only ATA showed a significant correlation [odds ratio (OR) 1.891, 95% confidence interval (95% CI) 1.273–2.840, P = .0018) while higher CRP favoured the risk of lower IL6RR (OR 0.9101, 95% CI 0.868–0.949, P CONCLUSION In SARS-CoV-2 CHD patients treated with OLHDF, ATA showed a better anti-inflammatory profile than PMMA, in particular regarding IL-6 RR.

BACKGROUND AND AIMS The QTc interval is a marker of arrhythmic risk in dialysis patients, and its lengthening has been associated with an increased risk of sudden death [1]. This phenomenon could be due to the accumulation of uremic toxins and their rapid removal with dialysis causing an imbalance of electrolytes currents [2]. The aim of the study is to describe the kinetics of potassium (K+) and other electrolytes during and after dialysis with the goal of validate a mathematical model for predicting the respective kinetics [3]. The secondary endpoint is to identify a correlation between the kinetics of intra (Ki) and extracellular K+ (Ke) during and after dialysis and the QTc interval. METHOD A total of 6 anuric HD patients were enrolled in an interventional, exploratory, prospective study. Clinical and pharmacological factors favouring the onset of arrhythmias or influencing the total mass of K + were excluded. Ki and Ke, Ca2+ Na, blood gas analysis, glucose and urea every 30 min were assessed during a 4 h HFR Supra dialysis session, the subsequent 7 h and at the start of the following session after 48 h. A 12-lead ECG was performed with the same schedule, and a bioimpedance vector analysis (BIVA) was obtained at the start and the end of the dialysis and 1 and 7 h after dialysis. Dialysate electrolytes were Na 140 mEq/L, K 3 mEq/L, Ca2+ 1.5 mEq/L and HCO3– 30 mmol/L. A selective ion probe was used to measure K+; the Ki value was obtained by an indirect formula expressed in a previous study [4]. The model of K + kinetics includes the Na+/K+/ATPase-dependent pump, the passive diffusion of K + from the intracellular to the extracellular compartment, the diffusion of K + through the filter, the intradialytic volume variation, the K + and solute rebound after dialysis, and the role of plasma osmolality [3]. RESULTS The model showed a better correlation to the in vivo data during the HFR phase than the post-dialytic one regarding Ke, sodium, HCO3– and Ca2+. The wide variability recorded by Ki is significantly in contrast with the stability predicted by the model, and the entity of post-dialysis Ca2+ drop was greater than that predicted by the model. Kinetics prediction of urea had a precise fitting with in vivo data in every phase. In Table 1, the in vivo results of the 6 patients regarding Ke, Ki, Ki/Ke, Ca2+ and QTc during and after HFR are resumed. In Fig. 1, we see the data extrapolated from a patient (likewise the others), where the greatest waving of the QTc occurred in the first hour post HFR in parallel with fluctuations of Ki and Ki/Ke. CONCLUSION The mathematical model for the prediction of the kinetics of solutes has shown a good correspondence with the in vivo data of K+, sodium, urea, Ca2+ and HCO3– during HFR, although it still needs to be refined in the post-dialysis phase. The major discrepancies for Ki could be due to difficult analytical processing. As to the greater drop of Ca2+ compared with the predicted, it can be due to the role played by other Ca2+ compartments in addition to the intra and extracellular ones. Although during the intradialytic period we faced a shortening of the QTc interval with a significant reduction in Ke, greater Ki/Ke and an increase in Ca2+ the post-HFR period appeared to be the most critical period. This phase corresponded to the largest fluctuations in QTc values, Ki, Ki/Ke ratio, and to the rapid rebound of K + and the drop of Ca2+.

Preservation of a vascular access is crucial in the management of hemodialysis patients. In this regard, percutaneous transluminal angioplasty (PTA) is an effective tool if performed after an adequate understanding of preliminary fistulograms. The present case showed a chronic dysfunction of a radial-cephalic arteriovenous fistula (AVF) due to arterial occlusion and partially relieved by the spontaneous development of multiple small arteriovenous connections in the palmar region of the hand. This dense network had been so far able to ensure a sufficient retrograde blood flow for an effective hemodialytic performance. The angioplasty of the post-anastomotic stenotic segment of the radial artery was effective in restoring this neoformed AVF patency.