Multi-Center Two-Year Patency Outcomes of Endovascular Arteriovenous Fistulas (endoAVF) Created with a 4 French System.

PURPOSE: To assess multicenter two-year patency outcomes of endovascular arteriovenous fistulas (endoAVF) created with the WavelinQ device. MATERIALS AND METHODS: Patients who had fistulas created at three centers from January 2018 to December 2020 were included in this retrospective study. In total, 112 patients underwent endoAVF creation [40 females, 72 males; mean age 60 years (range 18-88)]. Data collected included patient demographics, location of fistula creation, interventions performed, and brachial artery flows pre- and post-creation. Two-year cumulative patency, functional patency, and primary patency were assessed with Kaplan-Meier methodology. Factors affecting patency and maturation were examined using the Cox proportional hazards model. RESULTS: Technical success defined as angiographically successful endoAVF creation was 97.3% (109/112). In 11 patients the fistula did not mature for dialysis use. For 98 patients (87%) with endoAVF maturation, 12- and 24-month cumulative patency was 94.3% and 91.7%. Functional patency (two-needle cannulation) at 12 and 24 months was 95.7% and 92.7%, respectively. Median maturation time is 95 days (IQR 51-231 days). Male gender and brachial vein coiling at the time of endoAVF creation were predictive of maturation. There were 34 censored events (four patients undergoing renal transplantation; 30 patients deceased). Number of reinterventions per patient year was 0.73 where 43 were maturation procedures and 101 were maintenance procedures. One Grade 3 complication occurred of arterial access puncture site pseudoaneurysm. CONCLUSION: A high two-year functional and cumulative patency following endoAVF creation with the WavelinQ device was observed in this multicenter real-world experience Level of Evidence: 3 Level of Evidence III.

International survey of radiocephalic arteriovenous fistula: ISRAF survey.

AIMS: The objective of this survey was to encompass the full scope of international practice, entailing all technical, non-technical, preoperative stratification and functional maturation (FM) of RCAVF. METHODS: The survey contained n = 19 questionnaires with n = 46 variables completed by n = 85 providers from n = 21 nations across n = 5 continents. The numerical values were subjected to mean with standard error whereas the nominal data to a non-parametric (Kruskal-Wallis & Spearman correlation test) and analysis of variance (ANOVA). The test of homogeneity, & probability was reported 95% confidence intervals (CI) alongside error plots. Furthermore, a decision and higher attribute tree model was constructed based on current survey for higher FM in RCAVF. RESULTS: FM is independently associated with volume of surgeon per year (procedures performed) (p < 0.01) [High Volume: 73% (95% CI, 68-77%) versus Average volume: 63% (95% CI, 59-66%) vs Low volume: 56% (95% CI, 51-61%)]. FM increased by 8% with every 20 more procedures per group of surgeons on end point of FM. Amongst continents: Australia, America, Asia and South America demonstrated higher FM to Africa & Europe (p < 0.05). UK possessed a lower FM 58% (95% CI, 48-68%) in comparison to the world & Europe respectively [65% (95% CI, 61-70%) vs 61% (95% CI, 58--65%)]. There was a positive causal link between angle of anastomosis at 30-76° (p < 0.01), longitudinal & S-shaped incision & arteriotomy length of 3 & 4 mm to higher FM (p < 0.05). CONCLUSION: FM in RCAVF is independently & incrementally associated with the volume of surgeon per year. There is a diverse inclusion, exclusion and technical approach in RCAVF creation. This survey advocates the importance of international collaboration and/or registry in assimilation, consolidate and development of consensus.

Is there a role of the kidney failure risk equation in optimizing timing of vascular access creation in pre-dialysis patients?

BACKGROUND: The aims of this study were to assess the utility of using the Kidney Failure Risk Equation (KFRE) as an indicator to guide timing of vascular access creation in pre-dialysis patients. MATERIALS AND METHODS: Patients referred for vascular access creation had KFRE calculated at the time of assessment and compared to standard criteria for referral. Receiver operating characteristic curves were produced for each parameter. The outcomes at 3 months, 6 months, and 1 year were used as time points for analysis. RESULTS: Two hundred and three patients were assessed, and full data sets were available on 190 (94.6%). Access was created in 156 patients (82.1%) with a fistula in 153 (98.7%). Only 65.7% initiated dialysis within the follow up period. Those patients with an AV access created (n = 156) 37 (23.7%) did not reach end stage over the entire follow up period. Of the remaining patients (n = 119) that reached end stage 72.2% (n = 86) started on an AVF/AVG and 27.7% (n = 33) on a CVC. Using ROC analysis for referral eGFR, ACR and KFRE predicting dialysis initiation predictors resulted in C statistics for eGFR, ACR, and KFRE2 of 0.68 (0.58-0.79), 0.75 (0.65-0.84), and 0.72 (0.62-0.81) at 3 months; 0.73 (0.65-0.81), 0.70 (0.62-0.78), and 0.75 (0.67-0.81) at 6 months; and 0.65 (0.57-0.72); 0.67 (0.59-0.75), and 0.68 (0.61-0.77) at 12 months. CONCLUSIONS: In a group of patients referred for vascular access creation the predictive models are relatively poor when applied to initiation of dialysis. The application of current guidelines to fistula creation appears to result in a high rate of unnecessary fistula formation and non-use. The study requires further evaluation in a test set of patients to confirm these findings and also identify where such risk based approaches may need modification.

Major adverse cardiovascular events and all-cause mortality after emergency general surgery among kidney failure patients.

BACKGROUND: Emergency general surgery (EGS) is associated with increased mortality, with kidney failure a contributing risk, but comparative outcomes between patients with kidney failure and the general population are lacking. METHODS: In this retrospective population-cohort study, data were analysed for all EGS procedures performed in England between 1 April 2004 and 31 March 2019. EGS was defined as partial colectomy, small bowel resection, cholecystectomy, appendicectomy, lysis of peritoneal adhesions, surgery for peptic ulcer, or laparotomy. The main outcome measure was major adverse cardiovascular events (MACEs) and all-cause mortality after surgery. RESULTS: From 691 064 procedures, 0.16 per cent (n = 1097) and 0.23 per cent (n = 1567) were performed on kidney transplant and dialysis recipients respectively. Laparotomy was the most frequent EGS procedure for kidney transplant (46 per cent of procedures, n = 507) and dialysis (45 per cent of procedures, n = 704) recipients, with the highest 30-day and 1-year mortality. In logistic regression analysis, both kidney failure cohorts had higher risk for experiencing MACEs in the postoperative interval after emergency laparotomy; within 3 months (dialysis; OR 2.44 (95 per cent c.i. 2.08 to 2.87), P < 0.001 and transplant; OR 2.05 (95 per cent c.i. 1.57 to 2.68), P < 0.001) and within 1 year (dialysis; OR 2.39 (95 per cent c.i. 2.06 to 2.77), P < 0.001 and transplant; OR 2.21 (95 per cent c.i. 1.76 to 2.77), P < 0.001); however, in a propensity-score-matched cohort, increased risk for MACEs was observed among dialysis patients after emergency laparotomy (HR 2.10 (95 per cent c.i. 1.82 to 2.43), P < 0.001) but not kidney transplant recipients (HR 1.17 (95 per cent c.i. 0.97 to 1.41), P = 0.096). CONCLUSION: Mortality after emergency surgery is higher for patients with kidney failure and dialysis is worse than kidney transplantation, with cardiovascular deaths more common than the general population.

Age is just a number: Is frailty being ignored in vascular access planning for dialysis?

Current international guidelines advocate fistula creation as first choice for vascular access in haemodialysis patients, however, there have been suggestions that in certain groups of patients, in particular the elderly, a more tailored approach is needed. The prevalence of more senior individuals receiving renal replacement therapy has increased in recent years and therefore including patient age in decision making regarding choice of vascular access for dialysis has gained more relevance. However, it seems that age is being used as a surrogate for overall clinical condition and it can be proposed that frailty may be a better basis to considering when advising and counselling patients with regard to vascular access for dialysis. Frailty is a clinical condition in which the person is in a vulnerable state with reduced functional capacity and has a higher risk of adverse health outcomes when exposed to stress inducing events. Prevalence of frailty increases with age and has been associated with an increased risk of mortality, hospitalisation, disability and falls. Chronic kidney disease is associated with premature ageing and therefore patients with kidney disease are prone to be frailer irrespective of age and the risk increases further with declining kidney function. Limited data exists on the relationship between frailty and vascular access, but it appears that frailty may have an association with poorer outcomes from vascular access. However, further research is warranted. Due to complexity in decision making in dialysis access, frailty assessment could be a key element in providing patient-centred approach in planning and maintaining vascular access for dialysis.

Percutaneous arteriovenous fistula creation with the 4F WavelinQ EndoAVF System.

BACKGROUND: Percutaneous devices for creation of native arteriovenous fistulae offer an alternative to traditional open surgical techniques. The 4F WavelinQ EndoAVF System was developed as a lower profile alternative to facilitate access through smaller vessels and minimize access site complications; The current report is the original first experience of this device, assessing outcome in 120 patients followed for 6 months. METHODS: The use of the 4F WavelinQ system in three studies, EASE (32 patients), EASE-2 (24 patients), and the EU postmarket clinical follow-up study (64 patients) was aggregated and analyzed. Patients were followed with duplex ultrasound at discharge and follow-up visits at 1, 3, and 6 months. Primary, assisted primary, and secondary patency rates were evaluated as Kaplan-Meier estimates and standard errors. Time to maturity and time to successful cannulation were defined as the mean ± standard deviation days from the procedure in patients enrolled on dialysis. RESULTS: Procedural success was achieved in 116 patients (96.7%). Primary, assisted-primary, and secondary 6-month patency rates were 71.9% ± 4.5%, 80.7% ± 4.1%, and 87.8% ± 3.3%, respectively. Time to maturity averaged 41 ± 17 days. Time to successful cannulation averaged 68 ± 51 days. Device-related serious adverse events were reported in 3 of 120 patients (2.5%) and procedure-related serious adverse events occurred in 7 of 120 patients (5.8%). Arterial or venous access complications were not reported in any of the patients. Access circuit reinterventions were performed in 23 patients (19.2%), split between those performed for EndoAVF maturation (13/120 [10.8%]) and maintenance (11/120 [9.2%]). CONCLUSIONS: Percutaneous creation of native dialysis fistulae with the 4F WavelinQ EndoAVF System is safe and effective, with favorable durability and a low rate of serious complications and reinterventions through 6-month follow-up. Use of the 4F device allows for percutaneous fistula creation between the radial artery and radial vein or the ulnar artery and ulnar vein. These findings suggest that the 4F device is a useful percutaneous alternative to open surgical AVF or endovascular AVF with larger bore devices.

Health-related quality of life, uncertainty and coping strategies in solid organ transplant recipients during shielding for the COVID-19 pandemic.

Strict isolation of vulnerable individuals has been a strategy implemented by authorities to protect people from COVID-19. Our objective was to investigate health-related quality of life (HRQoL), uncertainty and coping behaviours in solid organ transplant (SOT) recipients during the COVID-19 pandemic. A cross-sectional survey of adult SOT recipients undergoing follow-up at our institution was performed. Perceived health status, uncertainty and coping strategies were assessed using the EQ-5D-5L, Short-form Mishel Uncertainty in Illness Scale (SF-MUIS) and Brief Cope, respectively. Interactions with COVID-19 risk perception, access to health care, demographic and clinical variables were assessed. The survey was completed by 826 of 3839 (21.5%) invited participants. Overall, low levels of uncertainty in illness were reported, and acceptance was the major coping strategy (92%). Coping by acceptance, feeling protected, self-perceived susceptibility to COVID-19 were associated with lower levels of uncertainty. Health status index scores were significantly lower for those with mental health illness, compromised access to health care, a perceived high risk of severe COVID-19 infection and higher levels of uncertainty. A history of mental health illness, risk perceptions, restricted healthcare access, uncertainty and coping strategies was associated with poorer HRQoL in SOT recipients during strict isolation. These findings may allow identification of strategies to improve HRQoL in SOT recipients during the pandemic.

Erratum: Preoperative assessment for percutaneous and open surgical arteriovenous fistula creation in patients for haemodialysis.

[This corrects the article DOI: 10.1093/ckj/sfz121.][This corrects the article DOI: 10.1093/ckj/sfz121.].

Macroscopic assessment of the quality of cold perfusion after deceased-donor kidney procurement: A United Kingdom population-based cohort study.

Concern regarding the quality of cold perfusion (QOP) during macroscopic assessment of procured kidneys is a common reason for discard. In the UK, QOP is routinely graded by both retrieving and implanting teams during back-bench surgery as: 1 (good), 2 (fair), 3 (poor) or 4 (patchy). We evaluated the association of this grading with organ utilization, graft outcomes, and agreement between teams. Data on all deceased-donor kidneys procured between January 2000 and December 2016 were analyzed for discard rates, while association with graft outcomes was studied in single adult transplants. Of 31,167 kidneys procured, 90.6%, 5.7%, 1.7%, and 2.1% were assigned grades 1, 2, 3, and 4, respectively, at retrieval. QOP was an independent risk factor of discard, with the highest rates observed in grade 3 kidneys (41.8%), compared to 6.5% in grade 1 (aOR 7.67, 95% CI 5.44-10.82, p < .001). Grading at retrieval was an independent predictor of delayed graft function (p = .019) and primary non-function (p = .001), but not long-term graft survival (p = .111). Implanting grade was an independent predictor of all three outcomes (p < .001, p < .001, and p = .002, respectively). Consistency of grading between teams was poor (Kappa = 0.179). QOP influences utilization and predicts outcomes, but a standardized and validated scoring system is required.

Preoperative assessment for percutaneous and open surgical arteriovenous fistula creation in patients for haemodialysis.

Preoperative assessment prior to surgical arteriovenous fistulas (AVFs) including ultrasound-guided mapping has been shown to have beneficial effects on their immediate success as well as early outcomes. This has led to their wide acceptance and adoption however clinical practice criteria is variable and is reflected in variabilities in practice. When transposing this to percutaneously created endovascular AVFs (endoAVFs), variable preoperative assessment criteria could equally result in variable practice and potentially subsequent and expectant outcomes. We aimed to review literature on reported validated methodologies and workflows of preoperative assessment for surgical AVF creation as reported in highest levels of available evidence, specifically randomized controlled trials. Published practice recommendations and guidelines on best clinical practice as well as systematic reviews and meta-analyses of published studies were also reviewed. Data on practice methodology from identified trial publications and protocols was collated and a summative narrative synthesis was carried out which compared these methodologies to additional assessments that may be required when targeting assessment for percutaneous endoAVF formation, based on our units experience as part of an international multicentre trial. In this review we present a brief overview of published literature and guidelines and propose a unified and uniform workflow for preoperative assessment for surgical AVFs and endoAVFs to aide clinical and imaging practice.

Recipient and allograft survival following donation after circulatory death versus donation after brain death for renal transplantation: A systematic review and meta-analysis.

BACKGROUND-OBJECTIVES: Current evidence based on retrospective and prospective studies demonstrates that donation after circulatory death (DCD) grafts are more susceptible to delayed graft function (DGF) than donation after brain death (DBD) grafts. The short- and long-term survival outcomes of the two cohorts are unclear. Therefore, we performed a systematic review and meta-analysis to estimate the patient and allograft survival outcomes for DCD and DBD in renal transplant surgery. METHODS: Systematic literature searches were conducted by searching various databases. Fixed and random effects models were used to assess the accumulation of evidence over time. RESULTS: The five-year patient survival rate was significantly better in the DBD than in the DCD cohort. Non-significant differences were observed in 1-, 3- and 10-year patient survival and in the 1-, 3-, 5-, and 10-year graft survival rates between the two cohorts. The acute rejection rate was lower in the DCD cohort than in the DBD cohort. Extended criteria of donor status, delayed graft function and primary non-function were significantly higher in the DCD cohort than in the DBD cohort. CONCLUSIONS: This study demonstrates that the short- and long-term survival graft and patient benefits are similar between DCD and DBD kidney transplants. Therefore, large, controlled DCD kidney programmes are urgently needed worldwide in order to increase the number of kidney transplants.

Rapid, highly accurate and cost-effective open-source simultaneous complete HLA typing and phasing of class I and II alleles using nanopore sequencing.

Accurate rapid genotyping of the genes within the HLA region presents many difficulties because of the complexity of this region. Here we present the results of our proof of concept nanopore-based long read polymerase chain reaction (PCR) solution for HLA genotyping. For 15 HLA anthropology-based samples and 13 NHS Blood and Transplant derived samples 40 ng of genomic DNA underwent long-range PCR for class I and II HLA alleles. Pooled PCR products were sequenced on the Oxford Nanopore MinIoON R9.4.1 flow cell. Sequenced reads had HLA genotype assigned with HLA-LA. Called genotypes were compared with reference derived from a combination of short-read next-generation sequencing, Sanger sequence and/or single-site polymorphism (SSP) typing. For concordance, accuracy was 100%, 98.4%, 97.5% and 95.1% for the first, second, third and fourth fields, respectively, to four field accuracy where it was available, otherwise three field in 28 samples for class I calls and 17 samples for class II calls. Phasing of maternal and paternal alleles, as well as phasing based identification of runs of homozygosity, was shown successfully. Time for assay run was 8 hours and the reconstruction of HLA typing data was 15 minutes. Assay cost was £55 ($80USD)/sample. We have developed a rapid and cost-effective long-range PCR and nanopore sequencing-based assay that can genotype the genes within HLA region to up to four field accuracy, identify runs of homozygosity in HLA, reconstruct maternal and paternal haplotypes and can be scaled from multi-sample runs to a single sample.

WavelinQ created arteriovenous fistulas versus surgical radiocephalic arteriovenous fistulas? A single-centre observational study.

PURPOSE: Devices to permit percutaneous endovascular arteriovenous fistula formation have recently been introduced into clinical practice with promising initial evidence. As guidelines support a distal fistula first policy, the question of whether an endovascular arteriovenous fistula should be performed as an initial option is introduced. The aims of this study were to compare a matched cohort of endovascular arteriovenous fistula with surgical radiocephalic arteriovenous fistulas. MATERIALS AND METHODS: Using data from a prospectively collected database over a 3-year period, a matched comparative analysis was performed. RESULTS: WavelinQ arteriovenous fistulas (group W, n = 30) were compared with radiocephalic arteriovenous fistulas (group RC; n = 40). Procedural success was high with 96.7% for group W and 92.6% for group RC. Primary patency at 6 and 12 months was greater in group W (65.5% 6mo and 56.5% 12mo) compared to group RC (53.4% 6mo and 44% 12mo) (p = 0.69 and 0.63). Mean primary patency was significantly lower for RC (235 ± 210 days) vs W (362 ± 240 days) (p < 0.05). Secondary patency for group W was 75.8% and 69.5% at 6 and 12 months, respectively. Secondary patency for RC was lower at 66.7% and 57.6% at 6 and 12 months, respectively. CONCLUSION: Outcomes of WavelinQ arteriovenous fistulas in this series are similar to published results. When compared to a contemporaneously created group of surgical fistulas, WavelinQ demonstrated superior outcomes. These data would support that WavelinQ endovascular arteriovenous fistulas may be considered as a first option in the access pathway particularly if vessels at the wrist are absent or less than ideal.

Quality improvement in vascular access: The role of patient-reported outcome measures.

Quality improvement initiatives should be aimed to enhance clinical outcomes, service delivery and quality of life for patients. For patients reliant on haemodialysis, vascular access is a lifeline. Survival differences relating to the type of vascular access are evident and many initiatives have focussed on increasing absolute rates of arteriovenous fistulas and/or decreasing central venous catheter use. While these have achieved some success quantitatively, the qualitative effects are less obvious. The aims of this review article are to explore the concepts of quality of care in vascular access. There is a paucity of studies into the effects of vascular access on the quality of life of dialysis patients, and where studies have been performed, generalised patient-reported outcome measures have been used. To facilitate the implementation of quality improvement programmes specifically for vascular access requires suitable tools. While existing patient-reported outcome measures may be applicable to vascular access, it is likely that these will require further evaluation, and the development of vascular access-specific patient-reported outcome measures may be required.

Options for end stage vascular access: Translumbar catheter, arterial-arterial access or right atrial graft?

BACKGROUND: Running out of vascular access for dialysis is thankfully rare, but despite this, most units will have a number of patients with few options and in a precarious state. The increasing longevity of dialysis patients portends more patients will reach minimal access options. End stage vascular access is poorly defined but classification may enable assessment and comparison of treatment options. Three options for patients with end stage access are a central venous catheter through a translumbar or transhepatic route, arterial-arterial prosthetic loop or a right atrial graft. AIMS: The aims of this study are to provide a structured review of evidence for these procedures to allow application and guide practice for patients with end stage vascular access. METHODS: A standardised search of published literature was performed of relevant studies. In addition, the references cited in those papers were assessed for any further available articles. All study types were included and reviewed by two authors independently. Primary outcomes were patient survival and secondary patency rate at 3 and 12 months. Secondary outcomes were long-term patency rates, mean time to cannulation and complications such as access dysfunction, thrombosis and infection. SUMMARY: Based on the available evidence, it would appear that arterial-arterial prosthetic loop is a definitive option for maintaining dialysis access in patients with no more arteriovenous access options. Translumbar and transhepatic dialysis catheters may offer short- and medium-term options and right atrial grafts may also be suitable as an option where arterial-arterial prosthetic loop is unsuitable.

Early experience and observations in endovascular dialysis fistula re-intervention.

In recent years, new emerging technology has allowed the endovascular creation of dialysis fistulas in the proximal forearm without the need for open surgery. Two such systems currently exist, and evidence to date has demonstrated high rates of technical success in fistula creation, high rates of dialysis functionality, and low rates of re-intervention using both systems. Whilst early trial data has demonstrated lower rates of re-intervention to maintain patency compared to surgical fistulas, endovascular re-interventions are still required to maintain functionality. The endovascular fistula (endoAVF) typically exhibits a shared drainage pattern and is morphologically distinct from the surgical fistula and patterns of failure observed often differ to what has been traditionally encountered. A fresh approach and understanding is therefore required and here we share our observations and experience of endovascular re-intervention in endoAVF created with the Wavelinq system.