Immediate access arteriovenous grafts versus tunnelled central venous catheters: study protocol for a randomised controlled trial

Background Autologous arteriovenous fistulae (AVF) are the optimal form of vascular access for haemodialysis. AVFs typically require 6 to 8 weeks to “mature” from the time of surgery before they can be cannulated. Patients with end-stage renal disease needing urgent vascular access therefore traditionally require insertion of a tunnelled central venous catheter (TCVC). TCVCs are associated with high infection rates and central venous stenosis. Early cannulation synthetic arteriovenous grafts (ecAVG) provide a novel alternative to TCVCs, permitting rapid access to the bloodstream and immediate needling for haemodialysis. Published rates of infection in small series are low. The aim of this study is to compare whether TCVC ± AVF or ecAVG ± AVF provide a better strategy for managing patients requiring immediate vascular access for haemodialysis. Methods/design This is a prospective randomised controlled trial comparing the strategy of TCVC ± AVF to ecAVG ± AVF. Patients requiring urgent vascular access will receive a study information sheet and written consent will be obtained. Patients will be randomised to receive either: (i) TCVC (and native AVF if this is anatomically possible) or (ii) ecAVG (± AVF). 118 patients will be recruited. The primary outcome is systemic bacteraemia at 6 months. Secondary outcomes include culture-proven bacteraemia rates at 1 year and 2 years; primary and secondary patency rates at 3, 6, 12 and 24 months; stenoses; re-intervention rates; re-admission rate; mortality and quality of life. Additionally, treatment delays, impact on service provision and cost-effectiveness will be evaluated. Discussion This is the first randomised controlled trial comparing TCVC to ecAVG for patients requiring urgent vascular access for haemodialysis. The complications of TCVC are considered an unfortunate necessity in patients requiring urgent haemodialysis who do not have autologous vascular access. If this study demonstrates that ecAVGs provide a safe and practical alternative to TCVC, this could instigate a paradigm shift in nephrology thinking and access planning.</p

Teaching percutaneous renal biopsy using unfixed human cadavers

Background: Percutaneous renal biopsy (PRB) is an important diagnostic procedure. Despite advances in its safety profile there remains a small but significant risk of bleeding complications. Traditionally, operators train to perform PRB through tutor instruction and directly supervised PRB attempts on real patients. We describe an approach to teaching operators to perform PRB using cadaveric simulation. Methods: We devised a full day course hosted in the Clinical Anatomy Skills Centre, with places for nine candidates. Course faculty consisted of two Consultant Nephrologists, two Nephrology trainees experienced in PRB, and one Radiologist. Classroom instruction included discussion of PRB indications, risk minimisation, and management of complications. Two faculty members acted as models for the demonstration of kidney localisation using real-time ultrasound scanning. PRB was demonstrated using a cadaveric model, and candidates then practised PRB using each cadaver model. Results: Written candidate feedback was universally positive. Faculty considered the cadaveric model a realistic representation of live patients, while the use of multiple cadavers introduced anatomical variation. Conclusions: Our model facilitates safe simulation of a high risk procedure. This might reduce serious harm associated with PRB and improve patient safety, benefiting trainee operators and patients alike

Continued monitoring of acute kidney injury survivors might not be necessary in those regaining an estimated glomerular filtration rate > 60 mL/min at 1 year

Background. Severe acute kidney injury (AKI) among hospitalized patients often necessitates initiation of short-term dialysis. Little is known about the long-term outcome of those who recover to normal renal function. The aim of this study was to determine the long-term renal outcome of patients experiencing AKI requiring dialysis secondary to hypoperfusion injury and/or sepsis who recovered to apparently normal renal function. Methods. All adult patients with AKI requiring dialysis in our centre between 1 January 1980 and 31 December 2010 were identified. We included patients who had estimated glomerular filtration rate (eGFR) &gt;60 mL/min/1.73 m2 12 months or later after the episode of AKI. Patients were followed up until 3 March 2015. The primary outcome was time to chronic kidney disease (CKD) (defined as eGFR persistently &lt;60 mL/min/1.73 m2) from first dialysis for AKI. Results. Among 2922 patients with a single episode of dialysis-requiring AKI, 396 patients met the study inclusion criteria. The mean age was 49.8 (standard deviation 16.5) years and median follow-up was 7.9 [interquartile range (IQR) 4.8–12.7] years. Thirty-five (8.8%) of the patients ultimately developed CKD after a median of 5.3 (IQR 2.8–8.0) years from first dialysis for AKI giving an incidence rate of 1 per 100 person-years. Increasing age, diabetes and vascular disease were associated with higher risk of progression to CKD [adjusted hazard ratios (95% confidence interval): 1.06 (1.03, 1.09), 3.05 (1.41, 6.57) and 3.56 (1.80, 7.03), respectively]. Conclusions. Recovery from AKI necessitating in-hospital dialysis was associated with a very low risk of progression to CKD. Most of the patients who progressed to CKD had concurrent medical conditions meriting monitoring of renal function. Therefore, it seems unlikely that regular follow-up of renal function is beneficial in patients who recover to eGFR &gt;60 mL/min/1.73 m2 by 12 months after an episode of AKI

Obstetric and long-term kidney outcomes in renal transplant recipients: a 40 year single-centre study

Female renal transplant recipients of childbearing age may ask what the outcomes are for pregnancy and whether pregnancy will affect graft function. We analyzed obstetric and transplant outcomes among renal transplant recipients in our center who have been pregnant between 1973 and 2013. A case−cohort study was performed identifying 83 pairs of pregnant and non-pregnant controls matched for sex, age, transplant vintage, and creatinine. There were 138 pregnancies reported from 89 renal transplant recipients. There were live births in 74% of pregnancies with high prevalence of prematurity (61%), low birth weight (52%), and pre-eclampsia (14%). Lower eGFR (OR 0.98; p = 0.05) and higher uPCR (OR 1.86; p = 0.02) at conception were independent predictors for poor composite obstetric outcome. Lower eGFR (OR 0.98; p = 0.04), higher uPCR (OR 1.50; p = 0.04), and live organ donation (OR 0.35; p = 0.02) were predictors of ≥20% loss of eGFR between immediately pre-pregnancy and one yr after delivery. There was no difference in eGFR at one, five, and 10 yr in pregnant women compared with non-pregnant controls and a pregnancy was not associated with poorer 10-yr transplant or 20-yr patient survival. Despite high rates of obstetric complications, most women had successful pregnancies with good long-term transplant function

Experienced physicians benefit from analyzing initial diagnostic hypotheses

Background: Most incorrect diagnoses involve at least one cognitive error, of which premature closure is the most prevalent. While metacognitive strategies can mitigate premature closure in inexperienced learners, these are rarely studied in experienced physicians. Our objective here was to evaluate the effect of analytic information processing on diagnostic performance of nephrologists and nephrology residents. Methods: We asked nine nephrologists and six nephrology residents at the University of Calgary and Glasgow University to diagnose ten nephrology cases. We provided presenting features along with contextual information, after which we asked for an initial diagnosis. We then primed participants to use either hypothetico-deductive reasoning or scheme-inductive reasoning to analyze the remaining case data and generate a final diagnosis. Results: After analyzing initial hypotheses, both nephrologists and residents improved the accuracy of final diagnoses (31.1% vs. 65.6%, p &lt; 0.001, and 40.0% vs. 70.0%, p &lt; 0.001, respectively). We found a significant interaction between experience and analytic processing strategy (p = 0.002): nephrology residents had significantly increased odds of diagnostic success when using scheme-inductive reasoning (odds ratio [95% confidence interval] 5.69 [1.59, 20.33], p = 0.007), whereas the performance of experienced nephrologists did not differ between strategies (odds ratio 0.57 [0.23, 1.39], p = 0.2). Discussion: Experienced nephrologists and nephrology residents can improve their performance by analyzing initial diagnostic hypotheses. The explanation of the interaction between experience and the effect of different reasoning strategies is unclear, but may relate to preferences in reasoning strategy, or the changes in knowledge structure with experience

Risk factors of ischemic stroke and subsequent outcome in hemodialysis patients

Background and purpose: End stage renal disease (ESRD) requiring hemodialysis (HD) carries up to a 10-fold greater risk of stroke than normal renal function. Knowledge concerning risk factors and management strategies derived from the general population may not be applicable to those with ESRD. We studied a large ESRD population to identify risk factors and outcomes for stroke. Methods: All adult patients receiving HD for ESRD from 01/01/2007 to 31/12/2012 were extracted from the electronic patient record. Variables associated with stroke were identified by survival analysis; demographic, clinical, imaging and dialysis related variables were assessed and case-fatality determined. Follow-up was until 31/12/2013. Results: 1382 patients were identified (mean age 60.5 years, 58.5% male). The prevalence of AF was 21.2% and 59.4% were incident HD patients. 160 (11.6%) experienced a stroke during 3471 patient-years of follow-up (95% ischemic). Stroke incidence was 41.5/1000 patient-years in prevalent and 50.1/1000 patient-years in incident HD patients. Factors associated with stroke on regression analysis were prior stroke, diabetes and age at starting renal replacement therapy. AF was not significantly associated with stroke and warfarin did not affect stroke risk in warfarin treated patients. Fatality was 18.8% at 7, 26.9% at 28 and 56.3% 365 days after stroke.&lt;p&gt;&lt;/p&gt; Conclusions: Incidence of stroke is high in patients with ESRD on HD with high case-fatality. Incident HD patients had the highest stroke incidence. Many, but not all, important risk factors commonly associated with stroke in the general population were not associated with stroke in patients receiving HD

Hematuria is associated with more severe acute tubulointerstitial nephritis

Acute tubulointerstitial nephritis (ATIN) is a common cause of acute kidney injury. Although haematuria is a risk factor for the development of renal disease, no previous study has analyzed the significance of haematuria in ATIN. Retrospective, observational analysis of 110 patients with biopsy-proven ATIN was conducted. Results: Haematuria was present in 66 (60%) ATIN patients. A higher percentage of ATIN patients with haematuria had proteinuria than patients without haematuria (89.4% vs. 59.1%, p = 0.001) with significantly higher levels of proteinuria (median (interquartile range) protein:creatinine ratio 902.70 (513–1492) vs. 341.00 (177–734) mg/g, p <0.001). Moreover, those patients with more haematuria intensity had a higher urinary protein:creatinine ratio (1352.65 (665–2292) vs. 849.60 (562–1155) mg/g, p = 0.02). Those patients with higher proteinuria were more likely to need renal replacement therapy (22.7 vs. 0%, p = 0.03) and to su er relapse (4 vs. 0%, p = 0.03). At the end of follow up, haematuric ATIN patients had higher serum creatinine levels (3.19 2.91 vs. 1.91 1.17 mg/dL, p = 0.007), and a trend towards a higher need for acute dialysis (7 vs. 1%, p = 0.09) and renal replacement therapy (12.1 vs. 2.3%, p = 0.12). Haematuria is common in ATIN and it is associated with worse renal function outcomesSupported by FIS/FEDER PI17/00130 and PI19/00815, Spanish Ministry of Science and Innovation (RYC-2017-22369 and DTS18/00032), Sociedad Española de Nefrología, Fundacion Renal Iñigo Álvarez de Toledo (FRIAT), ISCIII-RETIC REDinREN RD016/0009 Fondos FEDER, Comunidad de Madrid B2017/BMD-3686CIFRA2-CM, ERA-PerMed-JTC2018 (KIDNEY ATTACK AC18/00064 and PERSTIGAN AC18/00071)

Risk factors for bleeding complications after nephrologist-performed native renal biopsy

Background: Bleeding is a recognized complication of native percutaneous renal biopsy. This study aimed to describe the incidence of major bleeding after biopsy in a single centre over a 15-year period and examine factors associated with major bleeding. Methods: We identified consecutive adult patients undergoing ultrasound-guided native renal biopsy in the Glasgow Renal and Transplant Unit from 2000 to 2014. From the electronic patient record, we collected data pertaining to biopsy indication, pre- and post-biopsy laboratory measurements, prescribed medication and diagnosis. Aspirin was routinely continued. We defined major bleeding post-biopsy as the need for blood transfusion, surgical or radiological intervention or death. Binary logistic regression analysis was used to assess factors associated with increased risk of major bleeding. Results: There were 2563 patients who underwent native renal biopsy (1499 elective, 1064 emergency). The average age of patients was 57 (SD 17) years and 57.4% were male. Overall, the rate of major bleeding was 2.2%. In all, 46 patients required transfusion (1.8%), 9 patients underwent embolization (0.4%), no patient required nephrectomy and 1 patient died as a result of a significant late retroperitoneal bleed. Major bleeding was more common in those undergoing emergency compared with elective renal biopsy (3.4 versus 1.1%; P &lt; 0.001). Aspirin was being taken at the time of biopsy in 327 of 1509 patients, with no significant increase in the risk of major bleeding (P = 0.93). Body mass index (BMI) data were available for 546 patients, with no increased risk of major bleeding in 207 patients classified as obese (BMI &gt;30). Conclusions: The risk of major bleeding following native renal biopsy in the modern era is low. Complications are more common when biopsy is conducted as an emergency, which has implications for obtaining informed consent. Our data support the strategy of not stopping aspirin before renal biopsy

The utility of anti-Müllerian hormone in women with chronic kidney disease, on haemodialysis and after kidney transplantation

Women with renal disease have menstrual and gonadal dysfunction manifesting as hormonal imbalance. Anti-Müllerian hormone (AMH) is a potential measure of ovarian reserve. We examined circulating AMH concentrations in young women with renal failure, determined associations with clinical characteristics, and compared AMH with age-matched healthy individuals. AMH was measured in 77 women: 26 had chronic kidney disease (CKD), 26 were on haemodialysis (HD), and 25 had a kidney transplant. Random AMH levels were highest in women on HD [HD 2.9 (1.1–5.2), CKD 1.6 (0.7–2.2), transplant 1.5 (1.0–4.2) ng/ml]. On multiple linear regression, AMH was 53% higher [95% CI 0.20–0.98, P = 0.002] in women on HD and decreased by 20% per 5-year increase in age (P &lt; 0.001). AMH was 43% lower in women with renal failure compared with 600 age-matched controls [1.7 (0.9–3.8) versus 3.0 (1.9–5.0) ng/ml, P &lt; 0.001]; however, we found no difference in AMH between those on HD and healthy individuals [2.9 (1.1–5.2) versus 3.0 (1.9–5.0) ng/ml]. AMH may be a useful biomarker in female renal patients with non-dialysis dependent renal disease pursuing pregnancy. In contrast, AMH levels are higher in HD but unlikely to reflect ovarian reserve