Systematic review and meta-analysis of preoperative interventions to support the maturation of arteriovenous fistulae in patients with advanced kidney disease.

BACKGROUND: There is great potential to improve outcomes of arteriovenous fistulas (AVFs) by focusing more on the preoperative period of AVF creation. We aim to systematically review the evidence on safety and efficacy of various preoperative interventions that have been tried to improve AVF maturation and success rate. METHODS: We searched five databases: PubMed, Embase, CINAHL, Cochrane Library and King's Fund Library. Experimental studies that investigated the effect of various preoperative interventions to improve AVF outcomes among advanced chronic kidney disease (CKD) patients were searched. The effect size for primary outcome was calculated as the weighted mean difference in the final vessel calibre, rate of AVF maturation or primary failure between the intervention and control arm. We also assessed adverse effects and dropout rates. This review was preregistered in the International Prospective Register of Systematic Reviews (CRD42020193257). RESULTS: Eight eligible studies were identified involving three types of intervention: hand exercise (n = 6), cholecalciferol supplementation (n = 1) and pneumatic compression of the arm using a Fist Assist device (n = 1). The overall effect size of hand exercise on distal cephalic vein calibre was 0.24 mm [95% confidence interval (CI) 0.03-0.45] on meta-analysis of hand exercise studies. On restricting analysis to two randomized controlled trials (RCTs) that had independent control groups, the effect size was higher, at 0.29 mm (95% CI 0.11-0.47). Hand exercise was a well-tolerated intervention, especially when confined to the first 4 weeks. DISCUSSION: Hand exercise is the predominant intervention tried in the preoperative period of AVF creation, although there is methodological heterogeneity. Intermittent pneumatic compression using a Fist Assist device is a novel intervention that has shown some promise. Well-designed prospective RCTs are needed on preoperative interventions among advanced CKD patients, aimed at improving AVF outcomes.

Beta-glucans in advanced CKD: role in endotoxaemia and inflammation.

BACKGROUND/AIMS: (1-3)-ß-D glucans (BG) are cellular components of yeasts and fungi. Elevated blood levels may be an adjunct in diagnosing invasive fungal infection, though can be high in dialysis patients without fungaemia. BG can also induce false positive signals in endotoxin detection assays (Limulus Amoebocyte Lysate [LAL] assay). We explored the relationship between BG levels, renal impairment, endotoxaemia and inflammation. METHODS: We measured serum BG levels, markers of inflammation and blood endotoxin levels in 20 controls, 20 with stages 1-3 chronic kidney disease (CKD), 20 with stages 4-5 CKD, 15 on peritoneal dialysis (PD) and 60 on haemodialysis (HD). Another 30 patients were studied before and after HD initiation. RESULTS: BG levels increased with advancing CKD, being highest in HD patients, 22% of whom had elevated levels (> 80 pg/ml). Levels increased significantly following HD initiation. Levels also correlated positively with CRP, TNFα, IL-6 levels, independently of CKD stage. Blood endotoxin was detectable by LAL assays in 10-53% of the CKD cohort, being most prevalent in the HD group, and correlating positively with BG levels. Adding BG blocking agent to the assay reduced endotoxin detection confining it to only 5% of HD patients. Levels of inflammatory markers were higher in those with detectable endotoxin - whether false- or true positives. CONCLUSION: BG levels increased with decreasing renal function, being highest in dialysis patients. High BG levels were associated with false positive blood endotoxin signals, and with markers of inflammation, independently of CKD stage. The cause for high BG levels is unknown but could reflect increased gut permeability and altered mononuclear phagocytic system function.

Mitochondrial neurogastrointestinal encephalopathy: a clinicopathological mimic of Crohn's disease.

BACKGROUND: Mitochondrial neurogastrointestinal encephalopathy (MNGIE), due to mutations in TYMP, often presents with gastrointestinal symptoms. Two sisters, initially managed for Crohn's disease based upon clinical, imaging and pathological findings, were later found to have MNGIE. The cases provide novel clinicopathological insight, for two further reasons: both sisters remain ambulant and in employment in their late 20s and 30s; diagnosis in one sister was made after a suspected azathioprine-precipitated acute illness. CASE PRESENTATION: A 25-year-old female presented with diarrhoea, vomiting, abdominal pain, and bloating. Faecal calprotectin, colonic biopsies and magnetic resonance enterography were consistent with a diagnosis of Crohn's disease. Azathioprine initiation preceded admission with a sore throat, headache, myalgia, and pyrexia. Withdrawal led to rapid clinical improvement. MRI brain revealed persistent, extensive white matter changes. Elevated plasma and urine thymidine and deoxyuridine, and genetic testing for TYMP variants, confirmed MNGIE. Testing of the patient's sister, also diagnosed with Crohn's disease, revealed identical variants. In this context, retrospective review of colonic biopsies identified histological findings suggestive of MNGIE. CONCLUSIONS: Azathioprine interference in nucleic acid metabolism may interact with the mitochondrial DNA depletion of MNGIE. Nucleotide supplementation, proposed for treatment by manipulating mitochondrial nucleoside pools, may require caution. The late onset and mild phenotype observed confirms presentation can occur later in life, and may reflect residual thymidine phosphorylase activity. Clinicians should consider measuring plasma thymidine levels in suspected Crohn's disease to rule out MNGIE, particularly if white matter abnormalities are identified on neuroimaging.

Unexplained inflammation in end-stage kidney disease: Is the combination of enhanced gastrointestinal permeability and reticuloendothelial dysfunction its cause?

Unexplained chronic inflammation is prevalent in end-stage kidney disease, and contributes toward accelerated cardiovascular disease, and premature death. The source of inflammation is unclear, although increased gastrointestinal permeability is a likely contributory factor. Whether a "leaky" gut leads to penetration of the systemic circulation by gut-derived pathogens is at least partly dependent on Kupffer cell function. These resident liver macrophages are an important part of the reticuloendothelial system (RES), and there is evidence for Kupffer cell and reticuloendothelial dysfunction in chronic kidney disease. These observations are compatible with the inflammatory milieu of chronic kidney disease being of gut origin. Measuring gut permeability in chronic kidney disease is challenging. Use of fecal biomarkers and other novel serum biomarkers represent potential alternative tools. One such marker is (1-3)-Beta-D-glucan, a polysaccharide constituent of many fungal, bacterial, and plant cell walls; levels of (1-3)-Beta-D-glucan are elevated in hemodialysis patients. Gastrointestinal permeability and impaired removal by the RES may contribute to these high levels, suggesting potential importance as a biomarker. High levels of (1-3)-Beta-D-glucan also falsely elevate endotoxin measurements. Measuring the contribution of gastrointestinal permeability and RES dysfunction to systemic inflammation may be an important step in designing therapies to reduce systemic inflammation in chronic kidney disease.

Outcomes following surgery for fractured neck of femur in dialysis patients: a 5-year review from a district general hospital in the United Kingdom.

BACKGROUND: Neck of femur fractures are associated with high mortality and have increased prevalence in dialysis patients. Delays in operating on dialysis patients can occur as a result of logistical or medical issues; it has previously been shown that delays on operating on neck of femur fractures in the general population results in increased mortality. METHODS: Medical records of 27 dialysis patients admitted to a large district general hospital in the UK with a fractured neck of femur between January 2009 and January 2014 were analysed alongside records of 27 age and sex-matched non-dialysis patients. Fisher's exact test and the unpaired t test were applied to data to explore outcomes. Odds ratio was also used to compare mortality between the dialysis and non-dialysis groups. RESULTS: Thirty-day mortality amongst dialysis patients was 22 %, compared to 7 % in the non-dialysis cohort. One-year mortality amongst dialysis patients was 70 %, compared to 15 % in the non-dialysis cohort (odds ratio 13.7 (3.56-52.4, 95 % confidence interval; p = 0.0001)). Average length of survival in dialysis patients overall was 311 days; average length of survival if the patient was operated on within 48 h of admission was 450 days (192-708 days, 95 % confidence interval) and was 224 days (45-402, 95 % confidence interval) if operated on after more than 48 h of admission (p = 0.16). CONCLUSIONS: Dialysis patients had higher post-operative mortality than the non-dialysis cohort. Odds ratio for death was significantly greater at one-year in the cohort of dialysis patients compared to the non-dialysis patients. Delay to operation amongst the dialysis patient cohort did not contribute significantly to mortality in this study. The higher rates of coronary artery disease, diabetes mellitus and malignancy may confound mortality amongst patients on dialysis who sustain a fractured neck of femur. Limitations of this study included small patient numbers, data from only one centre being used, and some missing data for certain patients.

Prevalence and outcomes of chronic liver disease in patients receiving dialysis: systematic review and meta-analysis.

Background: Patients receiving dialysis for end-stage kidney disease (ESKD) commonly co-exhibit risk factors for hepatic impairment. This systematic review and meta-analysis aimed to quantify the coexistence of chronic liver disease (CLD) and characterize risk factors and outcomes. Methods: We searched the following databases from inception to May 2021: CINAHL, Cochrane Library, Embase, Kings Fund Library, MEDLINE and PubMed. The protocol was pre-registered on PROSPERO (study ID: CRD42020206486). Studies were assessed against three inclusion criteria: adults (>18 years) with ESKD receiving dialysis, primary outcome involving CLD prevalence and publications in English. Moderator analysis was performed for age, gender, study size and publication year. Sensitivity analysis was performed where applicable by removing outlier results and studies at high risk of bias. Results: Searches yielded 7195 articles; of these 15 met the inclusion criteria. A total of 320 777 patients were included. The prevalence of cirrhosis and non-alcoholic fatty liver disease (NAFLD) was 5% and 55%, respectively. Individuals with CLD had 2-fold higher mortality than those without {odds ratio [OR] 2.19 [95% confidence interval (CI) 1.39-3.45]}. Hepatitis B [OR 13.47 (95% CI 1.37-132.55)] and hepatitis C [OR 7.05 (95% CI 4.00-12.45)], but not diabetes, conferred increased cirrhosis risk. All studies examining NAFLD were judged to be at high risk of bias. We found no data on non-alcoholic steatohepatitis (NASH). Deaths from CLD, cancer and infection were greater among cirrhotic patients. Conclusions: CLD is prevalent in dialysis patients. Hepatitis B and C confer increased risk of CLD. The impact of NAFLD and NASH cirrhosis requires further study. CLD is associated with an increased risk of mortality in this setting.

Pauci-immune crescentic glomerulonephritis associated with metastatic rectal carcinoma.

Paraneoplastic glomerular disease is well recognised, although it most frequently presents with clinical features of the nephrotic syndrome. This case describes a 74-year-old male with metastatic rectal adenocarcinoma treated surgically with anterior resection followed by adjuvant capecitabine chemotherapy. Having previously had normal renal function, he developed an acute kidney injury with active urinary sediment following the discovery of liver metastases. A renal biopsy was performed, which revealed an active crescentic pauci-immune glomerulonephritis. The patient was treated with high dose oral corticosteroids which led to some improvement in renal function, although he was still left with significant kidney impairment, which limited further safe oncological treatment. This case highlights a rare presentation of glomerular disease in the setting of malignancy and also demonstrates the adverse impact that kidney impairment can have on outcomes in patients with cancer.

A single-centre, retrospective analysis of mortality over 80 months comparing paclitaxel-coated balloon versus standard balloon angioplasty in the treatment of dysfunctional arteriovenous access.

AIM: Percutaneous transluminal angioplasty (PTA) is a standard treatment for arteriovenous fistula (AVF) stenosis to preserve haemodialysis vascular access, promoting improved dialysis adequacy and better outcomes for those dependent on renal replacement therapy. Drug coated balloons (DCB) may help reduce the rate of neointimal hyperplasia and recurrent stenosis, but their use in femoropopliteal angioplasty has been associated with increased mortality at 2 and 5 year follow-up. This study aims to address the long-term safety of PTA for AVF stenosis with clinical correlation to participant co-morbidity and mortality. METHODS: All patients undergoing PTA for AVF stenosis at a single centre between 2013 and 2017 were identified and grouped according to the use of DCB versus standard balloon angioplasty. All data was anonymised and correlated to verify independent predictors of mortality. RESULTS: 481 (400 standard balloon; 81 DCB) procedures were performed in 313 patients (250 standard balloon; 63 DCB). Follow-up at 80 months did not show any difference in mortality (p = 0.546). Multivariate analysis identified time on dialysis (p < 0.001), age (p = 0.001) and Charlson comorbidity index (p = 0.02) as independent predictors of mortality. CONCLUSIONS: In this study, mortality was not associated with the use of DCBs, but was related to established factors of dialysis longevity, age and comorbidity.

Attitudes in Patients with Autosomal Dominant Polycystic Kidney Disease Toward Prenatal Diagnosis and Preimplantation Genetic Diagnosis.

AIMS: No recommendations currently exist regarding implementation of both prenatal diagnosis and preimplantation genetic diagnosis (PGD) for autosomal dominant polycystic kidney disease (ADPKD). This study evaluated attitudes in ADPKD patients with either chronic kidney disease (CKD) stages I-IV or end-stage renal failure (ESRF) toward prenatal diagnosis and PGD. METHODS: Ninety-six ADPKD patients were recruited from an outpatient clinic, wards, and dialysis units. Thirty-eight patients had ESRF and 58 had CKD stages I-IV. Participants were given an information sheet on prenatal diagnosis and PGD and subsequently completed a questionnaire. RESULTS: The median age of participants was 51.5 years. Seventeen percent of ADPKD patients with CKD and 18% of ADPKD patients with ESRF would consider prenatal diagnosis and termination of pregnancy for ADPKD. Fifty percent with CKD would have opted for PGD (or might consider it in the future) were it available and funded by the UK National Health Service, compared to 63% in the ESRF group (p = 0.33). Sixty-nine percent in the CKD group and 68% in the ESRF group believed that PGD should be offered to other patients. DISCUSSION: There was a spectrum of attitudes among this cohort. A proportion of patients believe that PGD should be made available to prospective parents with this disease. The discrepancy between the low proportion (17% CKD, 18% ESRF) who would consider prenatal diagnosis and termination of pregnancy and the higher number who hypothetically express an intention or wish to access PGD (50% CKD and 63% ESRF) indicates far greater acceptability for diagnostic methods that occur before embryo implantation. It is not known how the development of methods to identify patients whose renal function is likely to decline rapidly and treatments altering the natural history of ADPKD will affect these attitudes.