Duplex ultrasound-guided angioplasty of hemodialysis vascular access.

OBJECTIVE: Duplex ultrasound-guided angioplasty (DA) for hemodialysis vascular accesses remains questionable regarding its feasibility and safety. Minor complications (requiring no more treatment than nominal therapy) might be over-reported. Our hypothesis is that this procedure has no significant differences between observed rates and the recommended threshold of main outcomes of the procedure defined by the standards of arteriovenous fistulas (AVF) angioplasty. METHODS: In a single-center retrospective study, 298 DA performed on 141 patients from 2015 to 2019 were analyzed. Occluded AVF or concomitant use of radiographic guidance were excluded. Duplex ultrasound parameters were collected up to 1 month before, at the end of angioplasty, and on day 30 after the procedure. Complications were registered, and patency rates were studied at 24 months of follow-up. RESULTS: Anatomical success was achieved in 142 procedures (47.7%), clinical success in 284 (95.3%), and hemodynamic success in 283 (95.0%). Major complications-requiring at least a specific therapy-were reported in 8 procedures (2.7%) and minor complications-requiring no adjunctive therapy-in 157 (52.7%). At 24 months, overall postintervention primary patency was 34.0%, primary-assisted patency 87.4%, and secondary patency 92.5%. There were no significant differences of patency rates between groups with or without minor complications (P value for primary patency, 0.08; primary-assisted patency, 0.08; secondary patency, 0.23) or 30% residual stenosis (P value for primary patency, 0.82; primary-assisted patency, 0.46; secondary patency: 0.63). Duplex parameters further improved at postoperative day 30 after angioplasty. CONCLUSIONS: DA of AVF is feasible, safe-despite over-reported minor complications having no impact on postintervention patency rates-and efficient. A minor complication can be seen as an event without bad or good consequences. Anatomical definition of success does not fit on DA for hemodialysis vascular access. Further studies are required to define the duplex parameter threshold for efficacy.

Pain on arteriovenous fistula cannulation: A narrative review.

Pain on arteriovenous fistula (AVF) cannulation is a rather persistent problem in the daily hemodialysis practice. Its prevalence varies from 12% to even 80% depending on the definition and the pain-assessment tools and it affects the quality of life of hemodialysis patients. It is associated with fear of the cannulation process, the decision of hemodialysis from an AVF and sometimes the hemodialysis itself. In this narrative review, we tried to tackle the extent of the problem and to present the available published solutions. The literature suggests a large array of methods based on the application of local anesthetic creams, application of cold or hot directly on the cannulation sites or on the contralateral arm, cannulation techniques and AVF localization, distraction as well as alternative treatments. All of them have shown a relative success. There is a serious lack of large multicenter randomized trials and a gap concerning work groups and guidelines or recommendations from national or international societies on this matter. Complementary training starting from the predialysis patient education programs may be useful. Alternative prophylactic measures including counseling, hypnosis, or other physicochemical interventions could also improve our knowledge on the treatment of this seriously uncomfortable condition.

Extracorporeal photopheresis for the treatment of graft rejection in 33 adult kidney transplant recipients.

Background - Extracorporeal photopheresis (ECP) has shown encouraging results in the prevention of allograft rejection in heart transplantation. However, the role of ECP in kidney transplant (KT) rejection needs to be determined. Methods - This multicentre retrospective study included 33 KT recipients who were treated with ECP for allograft rejection (23 acute antibody-mediated rejections (AMRs), 2 chronic AMRs and 8 acute cellular rejections (ACRs)). The ECP indications were KT rejection in patients who were resistant to standard therapies (n = 18) or in patients for whom standard therapies were contraindicated because of concomitant infections or cancers (n = 15). Results - At 12 months (M12) post-ECP, 11 patients (33%) had a stabilization of kidney function with a graft survival rate of 61%. The Banff AMR score (g + ptc + v) was a risk factor for graft loss at M12 (HR 1.44 [1.01-2.05], p < 0.05). The factorial mixed data analysis identified 2 clusters. Patients with a functional graft at M12 tended to have cellular and/or chronic rejections. Patients with graft loss at M12 tended to have acute rejections and/or AMR; higher serum creatinine levels; DSA levels and histologic scores of AMR; and a longer delay between the rejection and ECP start than those of patients with functional grafts. Conclusions - ECP may be helpful to control ACR or moderate AMR in KT recipients presenting concomitant opportunistic infections or malignancies when it is initiated early.

Gastrointestinal Disorders in Peritoneal Dialysis Patients.

BACKGROUND: Gastrointestinal (GI) disorders in peritoneal dialysis (PD) patients are relatively understudied in the literature, even though they have a serious impact in the morbidity parameters and the quality of life for this group of patients. Various diagnostic tools have been used, including instrumental methods and questionnaires, invariably validated in comparative studies. SUMMARY: The prevalence of GI disorders is very high in PD patients. Compared to the haemodialysis patients they present a higher prevalence of reflux, eating dysfunction, gastroesophageal reflux, intestinal obstruction or adhesions and abdominal hernia. They may be divided into Gastric disorders (Gastroesophageal reflux disease, pathological Gastric emptying, Dyspepsia, Helicobacter pylori infection, peptic ulcers) and Intestinal disorders (Peritonitis, Diverticulosis, Constipation). Key Messages: The current paper is a review of the literature involving GI disorders in PD patients. This special group of patients with a special role of the peritoneal cavity and the GI motility in the physiology of their dialysis merit a larger number of studies dealing with the interrelation of the GI tract and the PD physiological, functional and pathophysiological parameters.

Evidence for anti-inflammatory effects of exercise in CKD.

CKD is associated with a complex state of immune dysfunction characterized by immune depression, predisposing patients to infections, and immune activation, resulting in inflammation that associates with higher risk of cardiovascular disease. Physical exercise may enhance immune function and exert anti-inflammatory effects, but such effects are unclear in CKD. We investigated the separate effects of acute and regular moderate-intensity aerobic exercise on neutrophil degranulation (elastase release), activation of T lymphocytes (CD69 expression) and monocytes (CD86 and HLA-DR expression), and plasma inflammatory markers (IL-6, IL-10, soluble TNF-receptors, and C-reactive protein) in patients with predialysis CKD. A single 30-minute (acute) bout of walking induced a normal pattern of leukocyte mobilization and had no effect on T-lymphocyte and monocyte activation but improved neutrophil responsiveness to a bacterial challenge in the postexercise period. Furthermore, acute exercise induced a systemic anti-inflammatory environment, evidenced by a marked increase in plasma IL-10 levels (peaked at 1 hour postexercise), that was most likely mediated by increased plasma IL-6 levels (peaked immediately postexercise). Six months of regular walking exercise (30 min/d for 5 times/wk) exerted anti-inflammatory effects (reduction in the ratio of plasma IL-6 to IL-10 levels) and a downregulation of T-lymphocyte and monocyte activation, but it had no effect on circulating immune cell numbers or neutrophil degranulation responses. Renal function, proteinuria, and BP were also unaffected. These findings provide compelling evidence that walking exercise is safe with regard to immune and inflammatory responses and has the potential to be an effective anti-inflammatory therapy in predialysis CKD.

Vitamins in dialysis: who, when and how much?

Despite the significant technical evolution of the blood purification methods, cardiovascular morbidity and mortality in dialysis patients is still several times higher than that observed in the general population. Vitamins are playing a crucial role in multiple key metabolic pathways. Due to multiple factors, dialysis patients present very often hypo- or hypervitaminosis for a broad range of vitamins. Dialysis in the context of renal replacement therapy is associated with a non-physiological potassium-sparing dietetic regime. Additionally, there is a non-selective intradialytic loss of micro- and macronutrients, deranged intracellular kinetics and gastrointestinal malabsorption due to uratemia. Frequent treatment with antibiotics due to infections associated with the acquired uremia-related immunosuppression may derange the vitamin-producing intestinal microflora. Certain agents prescribed in the context of renal failure or other conditions may reduce the absorption of vitamins from the gastrointestinal tract. These factors may deplete a dialysis patient from vitamins, especially the ones with antioxidant activity that may be associated with cardioprotective properties. In other cases, vitamins metabolized and excreted by the kidneys may be accumulated and exert toxic effects. The scope of this paper is to describe the main issues on vitamin therapy in dialysis patients in view of the ever contradictory opinions and practices.

Combined walking exercise and alkali therapy in patients with CKD4-5 regulates intramuscular free amino acid pools and ubiquitin E3 ligase expression.

Muscle-wasting in chronic kidney disease (CKD) arises from several factors including sedentary behaviour and metabolic acidosis. Exercise is potentially beneficial but might worsen acidosis through exercise-induced lactic acidosis. We studied the chronic effects of exercise in CKD stage 4-5 patients (brisk walking, 30 min, 5 times/week), and non-exercising controls; each group receiving standard oral bicarbonate (STD), or additional bicarbonate (XS) (Total n = 26; Exercising + STD n = 9; Exercising +XS n = 6; Control + STD n = 8; Control + XS n = 3). Blood and vastus lateralis biopsies were drawn at baseline and 6 months. The rise in blood lactate in submaximal treadmill tests was suppressed in the Exercising + XS group. After 6 months, intramuscular free amino acids (including the branched chain amino acids) in the Exercising + STD group showed a striking chronic depletion. This did not occur in the Exercising + XS group. The effect in Exercising + XS patients was accompanied by reduced transcription of ubiquitin E3-ligase MuRF1 which activates proteolysis via the ubiquitin-proteasome pathway. Other anabolic indicators (Akt activation and suppression of the 14 kDa actin catabolic marker) were unaffected in Exercising + XS patients. Possibly because of this, overall suppression of myofibrillar proteolysis (3-methylhistidine output) was not observed. It is suggested that alkali effects in exercisers arose by countering exercise-induced acidosis. Whether further anabolic effects are attainable on combining alkali with enhanced exercise (e.g. resistance exercise) merits further investigation.

Pulmonary hypertension in dialysis patients.

Pulmonary hypertension in end-stage renal disease patients is associated with significantly increased morbidity and mortality. The prevalence of pulmonary hypertension in dialysis patients is relatively high and varies in different studies from 17% to 49.53% depending on the mode of dialysis and other selection factors, such as the presence of other cardiovascular comorbidities. The etiopathogenic mechanisms that have been studied in relatively small studies mainly include arteriovenous fistula-induced increased cardiac output, which cannot be accomodated by, the spacious under normal conditions pulmonary circulation. Additionally, pulmonary vessels show signs of endothelial dysfunction, dysregulation of vascular tone due to an imbalance in vasoactive substances, and local as well as systemic inflammation. It is also believed that microbubbles escaping from the dialysis circuit can trigger vasoconstriction and vascular sclerosis. The non-specific therapeutic options that proved to be beneficial in pulmonary artery pressure reduction are endothelin inhibitors, phosphodiesterase inhibitor sildenafil, and vasodilatory prostaglandins in various forms. The specific modes of treatment are renal transplantation, size reduction or closure of high-flow arteriovenous fistulas, and transfer from hemodialysis to peritoneal dialysis-a modality that is associated with a lesser prevalence of pulmonary hypertension.

Benefits of regular walking exercise in advanced pre-dialysis chronic kidney disease.

BACKGROUND: There is increasing evidence of the benefit of regular physical exercise in a number of long-term conditions including chronic kidney disease (CKD). In CKD, this evidence has mostly come from studies in end stage patients receiving regular dialysis. There is little evidence in pre-dialysis patients with CKD Stages 4 and 5. METHODS: A prospective study compared the benefits of 6 months regular walking in 40 pre-dialysis patients with CKD Stages 4 and 5. Twenty of them were the exercising group and were compared to 20 patients who were continuing with usual physical activity. In addition, the 40 patients were randomized to receive additional oral sodium bicarbonate (target venous bicarbonate 29 mmol/L) or continue with previous sodium bicarbonate treatment (target 24 mmol/L). RESULTS: Improvements noted after 1 month were sustained to 6 months in the 18 of 20 who completed the exercise study. These included improvements in exercise tolerance (reduced exertion to achieve the same activity), weight loss, improved cardiovascular reactivity, avoiding an increase in blood pressure medication and improvements in quality of health and life and uraemic symptom scores assessed by questionnaire. Sodium bicarbonate supplementation did not produce any significant alterations. CONCLUSIONS: This study provides further support for the broad benefits of aerobic physical exercise in CKD. More studies are needed to understand the mechanisms of these benefits, to study whether resistance exercise will add to the benefit and to evaluate strategies to promote sustained lifestyle changes, that could ensure continued increase in habitual daily physical activity levels.

Rheopheresis: A narrative review.

INTRODUCTION: Rheopheresis is an extracorporal selective double-filtration procedure with an initial separation of plasma from the whole blood and a further filtration of the plasma through a second filter in order to eliminate a certain number of high molecular weight proteins such LDL, Lp(a), fibrinogen, α2-macroglobulin, Factor von Willebrand, and IgM Immunoglobulin. METHODS: In this narrative review we discuss the available data on the effects of Rheopheresis in various clinical conditions. RESULTS: Rheopheresis is considerd to exert a rapid effect on clinical conditions associated with seriously affected microcirculation and rheologic parameters such as, the dry age-related macular degeneration (AMD), sudden sensorineural hearing loss (SSHS), peripheral artery disease (PAD), calciphylaxis, systemic sclerosis and diabetic foot. CONCLUSIONS: Rheopheresis is a promising technique for conditions associated with affected microcirculatory rheologic parameters.

Identifying the performance and losses of a scroll compressor with vapour injection and R1234ze(E).

This work investigates a vapour injection scroll compressor integrated in a heat pump using the refrigerant R1234ze(E). The water-to-water heat pump was tested under a wide temperature range at the evaporator and condenser sides. The test results revealed that the performance is significantly reduced for lifts of over 30 K with the coefficient of performance being even below 2 and the maximum 2 nd law efficiency was just 28%. In order to enlighten the reasons behind such significant compressor underperformance, a semi-empirical model has been extended to include vapour injection, and a new improved modelling approach for the suction pressure drop was developed and implemented considering both the turbulent and laminar inlet flow regimes. Once the accuracy of the developed semi-empirical model was verified, the model was then adjusted to account for the R1234ze(E) operation, by fine-tuning its parameters based on the test data. The main loss mechanism identified is the high suction pressure drop, due to the high friction factor, with the inlet refrigerant flow possibly being laminar instead of turbulent. This resulted in a significant reduction of the mass flow rate and volumetric efficiency, while the standard model for suction pressure drop was not able to capture this effect.

Innovations thérapeutiques dans la prise en charge de l'anémie de la maladie rénale chronique Therapeutic innovations in the management of chronic kidney disease-associated anemia.

Anemia is a common complication of chronic kidney disease (CKD). The insufficient erythropoietin (EPO) production by the kidneys and iron deficiency are the main causes. Iron supplementation and the administration of recombinant EPO are the main treatment modalities. New iron formulations that can be administered orally, intravenously or directly via the dialysate have recently been developed to improve efficacy and tolerance. Ferric citrate administered orally can effectively corrects anemia in case of iron deficiency and in addition chelate phosphate in the gut lumen. Ferric carboxymaltose allows intravenous administration of larger doses given less frequently. Ferric pyrophosphate citrate administered directly via the dialysate allows the compensation of iron losses during the hemodialysis session. HIF-prolyl-hydroxylase inhibitors are a new therapeutic class of erythropoiesis-stimulating agents. Orally administered, they act by stabilizing the HIF transcription factor involved in the initiation of erythropoietin production by hypoxia. Several clinical studies have recently evaluated these new molecules in comparison with recombinant EPO. In CKD patients not yet on dialysis or undergoing dialysis therapy non-inferiority in correcting anemia has been demonstrated compared with recombinant EPO. The decrease in circulating hepcidin they induce appears greater than that induced by injectable recombinant EPO. Presently available reports on the safety of HIF-prolyl-hydroxylase inhibitors are reassuring but need to be confirmed in longer-term studies of larger size. © 2022 Published by Elsevier Masson SAS on behalf of Société francophone de néphrologie, dialyse et transplantation.

Methods based on a semi-empirical model for simulating scroll compressors with HFC and HFO refrigerants.

The aim of this work is to evaluate three methodologies regarding semi-empirical scroll compressor modeling for different refrigerants and conduct a comparative analysis of their results and accuracy. The first step is to improve a semi-empirical model for scroll compressors based on established techniques, and further enhance the physical background of some of its sub-processes leading to more accurate predictions. Focus is then given on the compressor operation when changing the refrigerant, proposing three methods in total. The first method refers to the standard model, requiring an optimization process for the calibration of all the model parameters. The second method relies on a reference refrigerant, and also uses optimization procedures, but for the fine-tuning of a small subset of the parameters. The third method is more generalized, without the need of any optimization process for the parameters identification, when fluid change occurs, leading to a very fast approach. Το evaluate the accuracy and verify the applicability of each method also related to the necessary computational time, two scroll compressors each with three different refrigerants are considered (HFCs and HFOs and their blends). The model is evaluated with the available manufacturer data, using R134a as reference refrigerant. The results show that the first method predicts the key indicators with a very high accuracy, with the maximum discrepancy of 2.06%, 4.17% and 3.18 K for the mass flow rate, electric power and discharge temperature respectively. The accuracy of the other two methods is dropping, but within acceptable levels in most of the cases. Therefore, in cases that reduced accuracy can be accepted, the third method is preferred for compressor performance prediction when changing the refrigerant, which provides results at a small fraction of time compared with the other two methods, once the parameters are calibrated for a reference case.

A Retrospective Comparison of Patient and Pressure Injury Data at Two Time Points in a Regional Hospital in France.

BACKGROUND: Pressure injuries (PIs) are a significant problem for health care institutions. PURPOSE: A retrospective study of patient data was conducted at a semi-urban state hospital in France, aiming to evaluate the rate of PIs and variables that may influence PI prevalence and care at 2 different time points. METHODS: Patient demographic, clinical, PI and PI prevention, and care variables were retrieved from the charts of all patients on all wards (except pediatrics and obstetrics) on October 20, 2009, and on October 24, 2013-4 years apart. Qualitative data were compared between the 2 dates using a t-test for independent variables. The remaining variables were compared using Pearson's chi-square method. P < .05 was considered significant. RESULTS: No significant differences were noted in PI rates (19% for 2009 and 16% for 2013) or the timing of their occurrence (51% occurred following admission in 2009, and 58.3% occurred after admission in 2013). Significant differences were found with regard to patient age (average, 73.97 and 76.22 years old in 2009 and 2013, respectively; P = .014) and rates of serious injuries (27% and 43% were stages 3 and 4 in 2009 and 2013, respectively; P = .010). Compared with 2009, in 2013, significantly more patients were placed on a specialty mattress and provided nutritional supplements and fewer were provided percutaneous endoscopic gastrostomy or nasogastric tubes. CONCLUSION: The rate of PIs was not different between these 2 time points despite improvements in the use of preventive and therapeutic measures, perhaps due to the increased age and frailty of the patient population in 2013 compared with 2009. Additional prospective research across multiple health care entities is warranted.

Comparison of the influence of angiotensin-converting enzyme inhibitor lisinopril and angiotensin II receptor antagonist losartan in patients with idiopathic membranous nephropathy and nephrotic syndrome.

OBJECTIVE: In this prospective study, the effects of an angiotensin-converting enzyme inhibitor [lisinopril (LIS)] and an angiotensin II receptor antagonist [losartan (LOS)] were compared in nephrotic patients with idiopathic membranous nephropathy. MATERIAL AND METHODS: Twenty-seven patients (13 males, mean age +/- SD 51.3 +/- 15.4 years) were treated with LIS (13 patients, six males, mean age 52.1 +/- 15.3 years) or LOS (14 patients, seven males, mean age 50.5 +/- 15.5 years) for 12 months. At baseline and after the treatment period, serum albumin, total cholesterol, estimated glomerular filtration rate (GFR), 24 h proteinuria and mean arterial pressure were determined. RESULTS: Proteinuria (g/24 h) was significantly reduced in both groups (LIS from 4.82 +/- 1.26 to 1.75 +/- 0.64, p < 0.0001; LOS from 4.55 +/- 1.09 to 2.54 +/- 1.94, p = 0.002) (all results +/- SD). Serum albumin levels (g/dl) increased significantly in both groups (LIS 2.27 +/- 0.41 to 3.17 +/- 0.63, p < 0.0001; LOS 2.93 +/- 0.40 to 3.55 +/- 0.44, p < 0.0001). GFR (ml/min x 1.73 m(2)) did not change significantly in either group (LIS 55 +/- 17 to 56 +/- 17, p = 0.65; LOS 64 +/- 18 to 59 +/- 16, p = 0.13). Total cholesterol (mg/dl) was significantly reduced only in the lisinopril group (LIS 347 +/- 81 to 266 +/- 64, p < 0.0001; LOS 306 +/- 58 to 263 +/- 77, p = 0.138). Mean arterial pressure (mmHg) was reduced in both groups (LIS 107 +/- 12 to 95 +/- 6, p < 0.0001; LOS 104 +/- 10 to 96 +/- 5, p = 0.003). In the comparison between the two groups, serum albumin levels were higher in the losartan group at baseline (p < 0.0001) and after 12 months (p = 0.029). There were no significant differences between the baseline and end-of-study values for the rest of the studied parameters. CONCLUSION: Treatment with lisinopril and losartan in nephrotic patients with idiopathic membranous nephropathy results in similar (and significant) effects on renal function, hypoalbuminaemia, proteinuria and blood pressure.

Quantitative evaluation of proteinuria by estimation of the protein/creatinine ratio in a random urine sample.

The aim of this study was to evaluate the severity of proteinuria using the protein/creatinine ratio in a random urine sample. In 45 patients (male 28, female 17; mean age 50.68 +/- 18.26 years) with proteinuria of various causes, we measured the 24-hour protein excretion per 1.73 m(2) of body surface and, during the same day, the protein/creatinine ratio in three different urine samples (8 am, 12 pm, 4 pm). The 24 h proteinuria was defined as mild (<1 g), moderate (1-3.4 g), and severe (>3.4 g) in 7, 27, and 11 patients, respectively. The sensitivity for protein/creatinine ratio compared to the 24 h proteinuria as a method of reference was 86-100% in the mild, 78-100% in the moderate, and 73-82% in the severe proteinuria, whereas the specificity was 84-100%, 78-83%, and 100% respectively. The patients with better renal function had significantly higher proteinuria levels. There was a similarity in the 24 h proteinuria and the protein/creatinine ratio measurements in all renal function and level-of-proteinuria groups. The protein/creatinine ratio of the morning and midday samples had a very good association with the 24 h sample, whereas it was not associated significantly with the evening sample (4 pm). In conclusion, the degree of 24 h proteinuria levels can be evaluated by calculating the protein/creatinine ratio in a random urine sample collected at any time from morning until midday. Protein/creatinine ratio is independent of the severity of proteinuria or renal function, and it can replace in clinical practice the cumbersome 24 h urine collections.

Lethal Strongyloides stercoralis superinfection in an immunocompromised patient.

In this article, we describe the case of a 49-year-old male gypsy on hemodialysis that was referred to our center due to high fever, breathlessness, and productive cough with bloody sputum. Forty-five days before hospitalization, he was treated for vasculitis with prednisolone and intravenous cyclophosphamide. Soon after admission he was resuscitated and intubated after a cardiac arrest. A large worm load of Strongyloides stercoralis larvae was identified in the sputum. The patient was treated with thiopental 25 mg/kgBW/12 h through a Levine tube and died 24 h later.

Comparison of immunosuppressive therapeutic regimens in patients with nephrotic syndrome due to idiopathic membranous nephropathy.

In this prospective randomized trial, we compared the effects of cyclosporine- and cyclophosphamide-based treatment regimens in patients with idiopathic membranous nephropathy. Twenty-eight patients were randomized to receive treatment with one of the three therapeutic regimens: cyclosporine with methylprednisolone, cyclophosphamide with methylprednisolone or lisinopril (control). Renal function and nephrotic syndrome parameters were determined at baseline and during a 9-month treatment period. At the end of the study period, renal function improved significantly in the cyclophosphamide and deteriorated significantly in the cyclosporine group. Serum albumin levels increased significantly in the cyclosporine and cyclophosphamide group. Total cholesterol levels and proteinuria were significantly reduced in all groups. In the comparison between the groups, serum albumin levels were significantly lower in the control group and there were no differences in the rest of the studied parameters at the end of the study. Six patients from the cyclosporine group (1/10 complete and 5/10 partial), all cyclophosphamide-treated (4/8 complete and 4/8 partial) and all 10 lisinopril-treated patients (10/10 partial) were on remission at the end of the study. In conclusion, cyclosporine-based regimens are not inferior to cyclophosphamide-based regimens. Cyclophosphamide is associated with more complete remissions after 9 months of treatment. Lisinopril is associated with a significant proteinuria reduction and without inducing any complete remissions.