Fistula First Initiative: Historical Impact on Vascular Access Practice Patterns and Influence on Future Vascular Access Care

Temporal trends in hemodialysis access creation during the fistula first era

OBJECTIVE

Although forearm arteriovenous fistulas (AVFs) are the preferred initial vascular access for hemodialysis based on national guidelines, there are no population-level studies evaluating trends in creation of forearm vs upper arm AVFs and arteriovenous grafts (AVGs). The purpose of this study was to report temporal trends in first-time permanent hemodialysis access type, and to assess the effect of national initiatives on rates of AVF placement.

METHODS

Retrospective cross-sectional study (2012-2022) utilizing the Vascular Quality Initiative database. All patients older than 18 years with creation of first-time upper extremity surgical hemodialysis access were included. Anatomic location of the AVF or AVG (forearm vs upper arm) was defined based on inflow artery, outflow vein, and presumed cannulation zone. Primary analysis examined temporal trends in rates of forearm vs upper arm AVFs and AVGs using time series analyses (modified Mann-Kendall test). Subgroup analyses examined rates of access configuration stratified by age, sex, race, dialysis, and socioeconomic status. Interrupted time series analysis was performed to assess the effect of the 2015 Fistula First Catheter Last initiative on rates of AVFs.

RESULTS

Of the 52,170 accesses, 57.9% were upper arm AVFs, 25.2% were forearm AVFs, 15.4% were upper arm AVGs, and 1.5% were forearm AVGs. From 2012 to 2022, there was no significant change in overall rates of forearm or upper arm AVFs. There was a numerical increase in upper arm AVGs (13.9 to 18.2 per 100; P = .09), whereas forearm AVGs significantly declined (1.8 to 0.7 per 100; P = .02). In subgroup analyses, we observed a decrease in forearm AVFs among men (33.1 to 28.7 per 100; P = .04) and disadvantaged (Area Deprivation Index percentile ≥50) patients (29.0 to 20.7 per 100; P = .04), whereas female (17.2 to 23.1 per 100; P = .03), Black (15.6 to 24.5 per 100; P < .01), elderly (age ≥80 years) (18.7 to 32.5 per 100; P < .01), and disadvantaged (13.6 to 20.5 per 100; P < .01) patients had a significant increase in upper arm AVGs. The Fistula First Catheter Last initiative had no effect on the rate of AVF placement (83.2 to 83.7 per 100; P=.37).

CONCLUSIONS

Despite national initiatives to promote autogenous vascular access, the rates of first-time AVFs have remained relatively constant, with forearm AVFs only representing one-quarter of all permanent surgical accesses. Furthermore, elderly, Black, female, and disadvantaged patients saw an increase in upper arm AVGs. Further efforts to elucidate factors associated with forearm AVF placement, as well as potential physician, center, and regional variation is warranted.

Arteriovenous access creation and hazards of hospitalization and death in patients starting hemodialysis

BACKGROUND

Recent evidence suggests an overestimation of the benefits associated with arteriovenous (AV) fistula versus graft in certain populations. We assessed hazards of all-cause and cause-specific hospitalization and death associated with AV access type in patients who started hemodialysis with a catheter in France, overall and by subgroups of age, sex and comorbidities.

METHODS

We performed a target trial emulation including patients who initiated hemodialysis with a catheter from 2010 through 2018 and were followed by the REIN Registry. We identified first-created fistula or graft through the French national health-administrative database. We used joint frailty models to deal with recurrent hospitalizations and potential informative censoring by death, and inverse probability weighting to account for confounding.

RESULTS

From the 18 800 patients included (mean age 68 ± 15 years, 35% women), 5% underwent AV graft creation first. The weighted hazard ratio (wHR) of all-cause hospitalization associated with graft was 1.08 [95% confidence interval (CI) 1.02 to 1.15], that of vascular access-related hospitalization was 1.43 (95% CI 1.32 to 1.55), and those of cardiovascular- and infection-related hospitalizations were 1.14 (95% CI 1.03 to 1.26) and 1.11 (95% CI 0.97 to 1.28), respectively. Results were consistent for most subgroups, except that the highest hazard of all-cause, cardiovascular- and infection-related hospitalizations with graft was blunted in patients with comorbidities (i.e. diabetes, wHR 1.01, 95% CI 0.93 to 1.10; 1.10, 95% CI 0.96 to 1.26; and 0.94, 95% CI 0.78 to 1.12, respectively).

CONCLUSIONS

In patients starting hemodialysis with a catheter, AV graft creation is associated with increased hazard of vascular access-related hospitalizations compared with fistula. This may not be the case for death or other causes of hospitalization.

Global variations in funding and use of hemodialysis accesses: an international report using the ISN Global Kidney Health Atlas

BACKGROUND

There is a lack of contemporary data describing global variations in vascular access for hemodialysis (HD). We used the third iteration of the International Society of Nephrology Global Kidney Health Atlas (ISN-GKHA) to highlight differences in funding and availability of hemodialysis accesses used for initiating HD across world regions.

METHODS

Survey questions were directed at understanding the funding modules for obtaining vascular access and types of accesses used to initiate dialysis. An electronic survey was sent to national and regional key stakeholders affiliated with the ISN between June and September 2022. Countries that participated in the survey were categorized based on World Bank Income Classification (low-, lower-middle, upper-middle, and high-income) and by their regional affiliation with the ISN.

RESULTS

Data on types of vascular access were available from 160 countries. Respondents from 35 countries (22% of surveyed countries) reported that > 50% of patients started HD with an arteriovenous fistula or graft (AVF or AVG). These rates were higher in Western Europe (n = 14; 64%), North & East Asia (n = 4; 67%), and among high-income countries (n = 24; 38%). The rates of > 50% of patients starting HD with a tunneled dialysis catheter were highest in North America & Caribbean region (n = 7; 58%) and lowest in South Asia and Newly Independent States and Russia (n = 0 in both regions). Respondents from 50% (n = 9) of low-income countries reported that > 75% of patients started HD using a temporary catheter, with the highest rates in Africa (n = 30; 75%) and Latin America (n = 14; 67%). Funding for the creation of vascular access was often through public funding and free at the point of delivery in high-income countries (n = 42; 67% for AVF/AVG, n = 44; 70% for central venous catheters). In low-income countries, private and out of pocket funding was reported as being more common (n = 8; 40% for AVF/AVG, n = 5; 25% for central venous catheters).

CONCLUSIONS

High income countries exhibit variation in the use of AVF/AVG and tunneled catheters. In low-income countries, there is a higher use of temporary dialysis catheters and private funding models for access creation.

Comparing post-maturation outcomes of arteriovenous grafts and fistulae

BACKGROUND

Though arteriovenous grafts (AVG) mature more reliably than arteriovenous fistulae (AVF) and require fewer maturation procedures (MP) to obtain functional patency, AVG are thought to have worse function after maturation. We explored differences in post-maturation outcomes between the following groups: AVF patients who did (AS-AVF) and did not (unAS-AVF) require assisted maturation and AVG patients who did (AS-AVG) and did not (unAS-AVG) require assisted maturation.

METHODS

Using the US Renal Data System (2012-2017), we retrospectively identified patients who initiated dialysis with a central venous catheter, underwent AVF or AVG placement and achieved successful two-needle cannulation. Primary patency and access abandonment after maturation were compared across groups using competing risks regression methods, generating sub-hazards ratios (sHR).

RESULTS

We identified 42,664 AVF and 12,335 AVG that met inclusion criteria. A larger proportion of AVFs required interventions: 18,408 AVF (43.2%) versus 2594 AVG (21.0%; p < 0.01). Both AS-AVG and AS-AVF patients experienced patency loss at 1 year more frequently compared with unAS-AVG (67.5% & 57.5% vs 55.2% respectively). Patency loss was lowest in unAS-AVF (38.9%). These trends were robust on adjusted analysis (unAS-AVG reference, AS-AVG sHR = 1.44, p < 0.01; AS-AVF sHR = 1.08, p < 0.01, unAS-AVF sHR = 0.67, p < 0.01). AS-AVGs were more likely to be abandoned than unAS-AVGs (11.7% unAS-AVG vs 17.2% AS-AVG). Fistulae, assisted or not, had lower unadjusted rates of 1-year abandonment than grafts (8.9% AS-AVF vs 7.3% unAS-AVF). On adjusted analysis, AVF usage was protective against abandonment (unAS-AVG, reference; AS-AVF sHR = 0.67, p < 0.01; unAS-AVF sHR = 0.59, p < 0.01) while AS-AVG was not (AS-AVG sHR = 1.32, p < 0.01).

CONCLUSIONS

unAS-AVF have the best long-term outcomes. AS-AVF lose primary patency at a higher rate than unAS-AVG. AVGs may be a better choice than AVFs if veins are marginal and likely to require assisted maturation. Further research is needed to identify anatomic and physiologic factors that affect long-term performance and influence conduit choice.

Assessing Time to Removal of Tunneled Dialysis Catheters after Arteriovenous Access Creation

BACKGROUND

Tunneled dialysis catheters (TDCs) are a temporary bridge until definitive arteriovenous (AV) access is established. Our objective was to evaluate the time to TDC removal in patients who underwent AV access creations with TDCs already in place.

METHODS

A single-center analysis of all AV access creations in patients with TDCs was performed (2014-2020). Primary outcome was time to TDC removal after access creation.

RESULTS

There were 364 AV access creations with TDCs in place. The average age was 58 years, 44% of patients were female, and 64% were Black. The median time to TDC removal was 113 days (range, 22-931 days) with 71.4% having a TDC >90 days after access creation. Patients with TDC >90 days were often older (60 vs. 54.7), had hypertension (98.1% vs. 93.3%), were diabetic (65.4% vs. 47.1%), and had longer average time to maturation (107.1 vs. 55.4 days, P < 0.001) and first access (114 vs. 59.4 days, P < 0.001). Multivariable analysis showed that older age was associated with prolonged TDC placement (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.05, P = 0.005) and prosthetic graft use was associated with shorter TDC indwelling time (OR 0.09, 95% CI 0.04-0.23, P ≤ 0.001). Kaplan-Meier analysis showed that 87% of TDCs were removed at 1 year.

CONCLUSIONS

The majority of patients with TDCs who underwent AV access creation had prolonged TDC placement. Prosthetic graft use was associated with shorter catheter times. Close follow-up after access placement, improving maturation times, and access type selection should be considered to shortened TDC times.

Vascular Access Perception and Quality of Life of Haemodialysis Patients

Background: Patient quality of life is widely used as a non-clinical determinant of care. For patients undergoing hemodialysis, vascular access is vital to the delivery of hemodialysis and its function may affect not only the clinical outcome of treatment but also the overall quality of life of the patient, highlighting the need for increased efforts to improve the quality of hemodialysis vascular access care. The objective of this study was to evaluate the correlation between vascular access perception and quality of life in patients undergoing hemodialysis. Methods: A total of 202 patients with active hemodialysis vascular access were included in the study. Quality of life was assessed using the Kidney Disease Quality of Life Instrument (KDQOL™) questionnaire, while vascular access perception was evaluated using the Vascular Access Questionnaire (VAQ). Results: The study presented evidence on the influence of vascular access for hemodialysis patients on their quality of life. This impact is related to factors directly associated with vascular access, such as the type of access and the patient's subjective evaluation of the access. Conclusions: The perception of vascular access is one of the factors that determines the quality of life of hemodialysis patients. The quality of life of hemodialysis patients decreases as the number of vascular access-related problems increases.

Characterization of long-term survival in Medicare patients undergoing arteriovenous hemodialysis access

BACKGROUND

Patients undergoing arteriovenous (AV) access creation for hemodialysis often have significant comorbidities. Our goal was to quantify the long-term survival and associated risks factors for long-term mortality in these patients to aid in optimization of goals and expectations.

METHODS

The Vascular Implant Surveillance and Interventional Outcomes Network Vascular Quality Initiative Medicare linked data was used to assess long-term survival in the HD registry. Demographics, comorbidities, and interventions were recorded. Because the majority of hemodialysis patients are provided Medicare, Medicare linkage was used to obtain survival data. Multivariable analysis was used to identify independent associations with mortality.

RESULTS

There were 13,945 AV access patients analyzed including 10,872 (78%) AV fistulas and 3073 (22%) AV grafts. The median age was 67 years and 56% of patients were male. Approximately one-third had a prior AV access and 44.7% had prior tunneled dialysis catheters. Patients receiving an AV fistula, compared with AV grafts, were more often younger, male, White, obese, independently ambulatory, preoperatively living at home, and less often have a prior AV access and tunneled dialysis catheters (P < .05 for all). The 5-year mortality overall was 62.9% with 61.2% for AV fistulas and 68.8% for AV grafts (P < .001). On multivariable analysis for 5 year mortality, nonambulatory status (hazard ratio [HR], 1.67; 95% confidence interval [CI], 1.53-1.83; P < .001), lower extremity access (HR, 1.67; 95% CI, 1.35-2.05; P < .001), human immunodeficiency virus or acquired immunodeficiency syndrome (HR, 1.44; 95% CI, 1.13-1.82; P < .001), White race (HR, 1.43; 95% CI, 1.35-1.51; P < .001), congestive heart failure (HR, 1.33; 95% CI, 1.26-1.41; P < .001), chronic obstructive pulmonary disease (HR, 1.23; 95% CI, 1.15-1.31; P < .001), and AV graft placement (HR, 1.12; 95% CI, 1.02-1.23, P = .016) were most associated with poor survival. Factors associated with improved survival were never smoking (HR, .73; 95% CI, 0.67-0.79; P < .001), prior/quit smoking (HR, .78; 95% CI, 0.72-0.84; P < .001), preoperative home living (HR, .75; 95% CI, 0.68-0.83; P < .001), and hypertension (HR, .89; 95% CI, 0.8-0.99; P = .03).

CONCLUSIONS

Long-term survival in Medicare patients undergoing AV access creation is poor with nearly two-thirds of patients having died at 5 years. There are many modifiable risk factors that may improve survival in these patients and give an opportunity for transplantation.

Snuffbox Versus Wrist Radiocephalic Arteriovenous Fistulas: 10 Years Experience

Background The wrist radiocephalic arteriovenous fistula (RCAVF) is the initial suggested procedure for establishing hemodialysis vascular access (HVA) in the most distal site of the upper limb. The anatomical snuffbox arteriovenous fistula (SBAVF) is barely utilised, despite its remote location. In this study, we aimed to analyse and compare the results of SBAVF and RCAVF in terms of their maturity, patency, and failure rates. Methodology This descriptive, retrospective study compared outcomes between SBAVF and RCAVF in terms of maturation, patency, and failure. All patients with chronic kidney disease who attended and underwent either procedure at Betsi Cadwaladr University Health Board between 2013 and 2023 were studied. Results In a period of 10 years, 179 patients were included. Overall, 102 (57%) were male and 77 (43%) were female, with a male-to-female ratio of 1.3:1. Wrist radiocephalic fistula was the dominant type of surgery done in 76% (n = 136), while the snuffbox radiocephalic fistula was done in fewer than 24% (n = 43) of patients. Most patients underwent a successful arteriovenous (AV) fistula (n = 105, 58.7%), in contrast to 67 patients whose fistulas failed. There was a significant relationship between fistula failure and complications (p = 0.000). There was no significant effect of the fistula site, hypertension, diabetes, cardiac diseases, smoking, peripheral vascular disease, or central vein stenosis on the failure of the AV fistula (p = 0.127, 0.534, 0.510, 0.397, 0.017, 0.68, and 0.371, respectively). Conclusions The snuffbox AV fistula is a suitable and feasible first choice for patients on hemodynamic therapy.

Interventions for thrombosed haemodialysis arteriovenous fistulas and grafts

BACKGROUND

Patients who present with problems with definitive dialysis access (arteriovenous fistula (AVF) or arteriovenous graft (AVG)) become catheter dependent (temporary access), a condition that often carries a higher risk of infections, central venous occlusions and recurrent hospitalisations. For AVG, primary patency rates are reported to be 30% to 90% in patients undergoing thrombectomy or thrombolysis. According to the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) guidelines, surgery is preferred when the cause of the thrombosis is a stenosis at the site of the anastomosis in thrombosed AVF. The European Best Practice Guidelines (EBPG) reported that thrombosed AVF may be preferably treated with endovascular techniques, but when the cause of thrombosis is in the anastomosis, surgery provides better results with re-anastomosis. Therefore, there is a need to carry out a systematic review to determine the effectiveness and safety of the intervention for thrombosed fistulae.

OBJECTIVES

This review aims to establish the efficacy and safety of interventions for failed AVF and AVG in patients receiving haemodialysis (HD).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 28 January 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Portal (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

The review included randomised controlled trials (RCTs) and quasi-RCTs in people undergoing HD treatment using AVF or AVG presenting with clinical or haemodynamic evidence of thrombosis. Patients had to have used an AVF or AVG at least once.

DATA COLLECTION AND ANALYSIS

Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Our search strategy identified 14 eligible studies (1176 randomised participants) for inclusion in this review. We included three types of interventions for the treatment of thrombosed AVF and AVG: (1) types of thrombectomy, (2) types of thrombolysis and (3) surgical procedures. Most of the included studies had a high risk of bias due to a poor study design, a low number of patients and industry involvement. Overall, there was insufficient evidence to suggest that a specific intervention was better than another for the outcomes of failure, primary patency at 30 days, technical success and adverse events (both major and minor). Primary patency at 30 days may improve with surgical compared to mechanical thrombectomy (3 studies, 404 participants: RR 1.36, 95% CI 1.07 to 1.67); however, the evidence is very uncertain. Death, access dysfunction, successful dialysis, and SONG (Standards Outcomes in Nephrology) outcomes were rarely reported. The current review is limited by the small number of available studies with a limited number of patients enrolled. Most of the studies included in this review have a high risk of bias and a low or very low certainty of evidence. Further research is required to define the most effective and clinically appropriate technique for access dysfunction.

AUTHORS' CONCLUSIONS

It remains unclear whether any intervention therapy affects the patency at 30 days or failure in any thrombosed HD AV access (very low certainty of evidence). Future research will very likely change the evidence base. Based on the importance of HD access to these patients, future studies of these interventions among people receiving HD should be a priority.

Safety and efficacy of a new covered stent in hemodialysis vascular access outflow stenosis: A Brazilian multicenter retrospective study

BACKGROUND

Vascular stenosis commonly leads to dysfunction in hemodialysis vascular access. Although percutaneous transluminal angioplasty is an established treatment, stent utilization has increased in the last decade as an alternative solution to extend the access function. This study evaluated the safety and initial results of a new impermeable covered stent for treating vascular access outflow stenosis.

METHODS

Investigators retrospectively analyzed 114 hemodialysis patients treated with polytetrafluorethylene-covered stents from September 2018 to September 2022 across four centers. Lesions treated were de novo or restenotic and located in the venous graft anastomosis, outflow segment, cephalic arch, and basilic swing point. Patients were followed by in-person physical examination at 1, 3, and 6 months, and Duplex ultrasound was performed to evaluate the vascular access circuit and in-stent restenosis. The primary efficacy endpoint was target lesion primary patency at 1, 3, and 6 months. Secondary endpoints included access circuit primary patency and secondary patency at 1, 3, and 6 months. The primary safety endpoint was freedom from local or systemic serious adverse events through 30 days post-procedure.

RESULTS

Forty-four patients had thrombosed access at the initial presentation, and 41 patients presented with recurrent stenosis. The target lesion primary patency rates at 1, 3, and 6 months were 100%, 89.4%, and 74%, respectively. The access circuit primary patency rates were 100% at 1 month, 85% at 3 months, and 62.7% at 6 months. The secondary patency rates at 1, 3, and 6 months were 100%, 96.4%, and 94.6%, respectively. In the adjusted multivariate Cox regression analysis, only recurrent lesions and female gender were associated with reduced primary patency rates. No serious adverse event was observed through the first 30 days post-procedure.

CONCLUSION

In this retrospective analysis, a new covered stent was shown to be safe and effective for treating peripheral outflow stenosis in vascular access.

Slowly moving the needle away from Fistula First

OBJECTIVE

In 2019, the management of end-stage kidney disease (ESKD) shifted away from "Fistula First" (FF) to "ESKD Life-Plan: Patient Life-Plan First then Access Needs." Indeed, some patients exhibit such excessive comorbidity that even relatively minor vascular surgery may be complicated. The purpose of this study was to retrospectively assess complications and mortality (and delineate operative futility) in patients undergoing arteriovenous fistula (AVF) creation in the FF era.

METHODS

Consecutive AVFs created in a single institution before 2021 were retrospectively reviewed. Operative futility was defined as never-accessed fistula, no initiation of dialysis, failure of access maturation (despite secondary intervention), hemodialysis access-induced distal ischemia requiring ligation, early loss of secondary patency, and/or patient mortality within the first 6 postoperative months.

RESULTS

A total of 401 AVFs were created including radial-cephalic (44%), brachial-cephalic (41%), and brachial-basilic (15%) constructions. Patients exhibited a mean age of 69 ± 15 years; 63% were male, and most (74%) were already being hemodialyzed at the time of fistula creation. Forty-five patients (11%) suffered a cardiac event, and five patients died (1%) within 90 days of their access surgery. Perioperative cardiac events were significantly more common after age 80 (19% vs 8%; P = .004); age >80 years was an independent predictor of major 90-day complications (odds ratio [OR], 1.88; 95% confidence interval [CI], 1.04-3.39; P = .036) and the sole independent predictor of major morbidity defined as cardiopulmonary complications, stroke, or death within the first year (OR, 2.01; 95% CI, 1.24-3.25; P = .004). Operative futility was encountered in 52% of the cohort (n = 208 patients): 40% (n = 160) of primary AVFs failed to mature despite assistance, 19% (n = 77) had lost secondary patency by 6 months, 13% of patients (n = 53) were never started on dialysis after access creation, 4% (n = 16) were dead by 6 months, 2% of AVFs (n = 10) matured but were never accessed, and 2% (n = 9) required ligation for hemodialysis access-induced distal ischemia. Not surprisingly, the sole independent protector against operative futility was that catheter-based dialysis had been established prior to AVF creation (OR, 0.36; 95% CI, 0.22-0.59; P < .01).

CONCLUSIONS

Approximately 50% of primary AVF operations performed in the aggressive FF era were deemed futile. Octogenarians were particularly prone to futility and complications during this era. A paradigm shift, from FF to an "ESKD Life-Plan" will, hopefully, more thoughtfully match vascular access strategies to individual patient needs.

Hemodialysis vascular access in elderly patients: A comprehensive review

The number of elderly patients initiating hemodialysis (HD) increased considerably over the past decade. Arteriovenous fistulas (AVFs) are the preferred vascular access (VA) type in most HD patients. Choice of VA for older hemodialysis patients presents a challenge. The higher incidence of comorbidities, longer AVF maturation times, risk of primary failure, risk of patency loss, and shorter life expectancy are important factors to consider. In this review we provide a comprehensive analysis on maturation rates, primary failure, patency, and mortality regarding vascular access in patients older than 75 years of age.

Predicting recurrent interventions after radiocephalic arteriovenous fistula creation with machine learning and the PREDICT-AVF web app

OBJECTIVE

Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines discourage ongoing access salvage attempts after two interventions prior to successful use or more than three interventions per year overall. The goal was to develop a tool for prediction of radiocephalic arteriovenous fistula (AVF) intervention requirements to help guide shared decision-making about access appropriateness.

METHODS

Prospective cohort study of 914 adult patients in the United States and Canada undergoing radiocephalic AVF creation at one of the 39 centers participating in the PATENCY-1 or -2 trials. Clinical data, including demographics, comorbidities, access history, anatomic features, and post-operative ultrasound measurements at 4-6 and 12 weeks were used to predict recurrent interventions required at 1 year postoperatively. Cox proportional hazards, random survival forest, pooled logistic, and elastic net recurrent event survival prediction models were built using a combination of baseline characteristics and post-operative ultrasound measurements. A web application was created, which generates patient-specific predictions contextualized with the KDOQI guidelines.

RESULTS

Patients underwent an estimated 1.04 (95% CI 0.94-1.13) interventions in the first year. Mean (SD) age was 57 (13) years; 22% were female. Radiocephalic AVFs were created at the snuffbox (2%), wrist (74%), or proximal forearm (24%). Using baseline characteristics, the random survival forest model performed best, with an area under the receiver operating characteristic curve (AUROC) of 0.75 (95% CI 0.67-0.82) at 1 year. The addition of ultrasound information to baseline characteristics did not substantially improve performance; however, Cox models using either 4-6- or 12-week post-operative ultrasound information alone had the best discrimination performance, with AUROCs of 0.77 (0.70-0.85) and 0.76 (0.70-0.83) at 1 year. The interactive web application is deployed at https://predict-avf.com.

CONCLUSIONS

The PREDICT-AVF web application can guide patient counseling and guideline-concordant shared decision-making as part of a patient-centered end-stage kidney disease life plan.

Robotic tomographic ultrasound and artificial intelligence for management of haemodialysis arteriovenous fistulae

BACKGROUND

Arteriovenous fistulae (AVF) and Arteriovenous Grafts (AVG) may present a problematic vascular access for renal replacement therapy (RRT), reliant on recurrent specialist nurse and medical evaluation. Dysfunctional accesses are frequently referred 'out of the dialysis clinic' for specialist sonographic examination, with associated delays potentiating loss of vascular access viability and/or need for emergency intervention. Definitive anatomical and functional diagnostics based in the dialysis unit may help to solve these delays and associated complications.

OBJECTIVES

This publication reports a novel vascular access monitoring concept, Robotic Tomographic Ultrasound (RTU).

RESEARCH DESIGN

Robotic Tomographic Ultrasound incorporates a semi-autonomous, robotic vascular ultrasound system and purpose designed analysis software that can be deployed at the point of care. Three-dimensional scan data, as well as conventional B-Mode and Doppler data are obtained by the system and transferred to a cloud based reporting and analysis software. Scans are remotely annotated and interpreted by a sonographer, with diagnostic data presented securely to clinicians on their preferred web based application/web connected device.

RESULTS

Software developed specifically for pre AVF mapping, maturation and monitoring protocols, analyse the data and then present interpreted results to all caring clinicians to assist with decision making. Vascular access planning can be determined with high confidence with data from the Map module. Maturation data can be presented in line with institutional requirements to the dialysis nurse, facilitating precocious needle access.

CONCLUSION

Robotic Tomographic Ultrasound is a novel approach to vascular access management that may reduce the risk of loss of functional access by regular monitoring with the system; automated alerts guiding clinicians to the need for pre-emptive intervention, and the potential to increase longevity of the vascular access.

Barriers to Implementing the Kidney Disease Outcomes Quality Initiative End-Stage Kidney Disease Life Plan Guideline

OBJECTIVE

The updated 2019 National Kidney Foundation Kidney Disease Outcomes Quality Initiative vascular access guidelines recommend patient-centered, multi-disciplinary construction and regular update of an individualized end-stage kidney disease (ESKD) Life-Plan (LP) for each patient, a dramatic shift from previous recommendations and policy. The objective of this study was to examine barriers and facilitators to implementing the LP among key stakeholders.

METHODS

Semi-structured individual interviews were analyzed using inductive and deductive coding. Codes were mapped to relevant domains in the Consolidated Framework for Implementation Research (CFIR).

RESULTS

We interviewed 34 participants: 11 patients with end-stage kidney disease, 2 care partners, and 21 clinicians who care for patients with end-stage kidney disease. In both the clinician and the patient/care partner categories, saturation (where no new themes were identified) was reached at 8 participants. We identified significant barriers and facilitators to implementation of the ESKD LP across three CFIR domains: Innovation, Outer setting, and Inner setting. Regarding the Innovation domain, patients and care partners valued the concept of shared decision-making with their care team (CFIR construct: innovation design). However, both clinicians and patients had significant concerns about the complexity of decision-making around kidney substitutes and the ability of patients to digest the overwhelming amount of information needed to effectively participate in creating the LP (innovation complexity). Clinicians expressed concerns regarding the lack of existing evidence base which limits their ability to effectively counsel patients (innovation evidence base) and the implementation costs (innovation cost). Within the Outer Setting, both clinicians and patients were concerned about performance measurement pressure under the existing "Fistula First" policies and had concerns about reimbursement (financing). In the Inner Setting, clinicians and patients stressed the lack of available resources and access to knowledge and information.

CONCLUSION

Given the complexity of decision-making around kidney substitutes and vascular access, our findings point to the need for implementation strategies, infrastructure development, and policy change to facilitate ESKD LP development.

Feasibility and safety of guidewire-balloon entrapment technique for recanalization of thoracic central vein occlusion in hemodialysis patients

OBJECTIVE

To explore the feasibility and safety of Guidewire-Balloon Entrapment Technique (GBET) for the recanalization of thoracic central vein occlusions (TCVOs) in hemodialysis patients.

METHODS

A retrospective observational study was conducted using data from 28 patients who required the establishment or maintenance of hemodialysis access and were treated with GBET for the recanalization of right-sided TCVOs from January 2017 to April 2021. Of the patients, 27 required tunneled cuffed catheter (TCC) placement or exchange, and 1 had an outflow tract occlusion of the Brescia-Cimino radio cephalic arteriovenous fistula (AVF).

RESULTS

A total of 26 patients successfully underwent TCC exchange and placement using GBET; 1 patient underwent successful recanalization of an occlusion of the outflow tract of the right Brescia-Cimino AVF; and 1 patient underwent successful TCC placement in the left internal jugular vein (LIJV) after the failure of TCC placement in the right internal jugular vein (RIJV). The success rate for GBET was 27/28 (96.43%), and there were no major complications.

CONCLUSION

GBET is a safe and effective method for the recanalization of right-sided TCVOs, especially for TCC exchange and placement, and can be used as a safe and easy approach for TCVO recanalization.

Estimating the effect of dialysis staffing ratio regulations on mortality and hospitalizations for Medicare hemodialysis patients

BACKGROUND AND OBJECTIVES

Eight states and Washington, DC have implemented regulations mandating a minimum ratio between treatment staff and patients receiving hemodialysis in a facility in an effort to improve the quality of hemodialysis treatment. Our investigation examines the association between minimum staffing regulations and patient mortality for four states and hospitalizations for two states that implemented these rules during our sample period.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We utilized a synthetic difference in differences estimation to analyze the effect of minimum staffing ratios on hemodialysis treatment quality, measured by deaths and hospitalizations for end-stage renal disease patients. We used data gathered by the US Renal Data System and aggregated at the state level.

RESULTS

We are unable to find evidence that mandated dialysis staffing ratios area associated with a reduction in mortality or hospitalizations. We estimate a slight reduction in deaths per 1000 patient hours and a slight increase in hospitalizations, but neither are statistically significant.

CONCLUSIONS

We were unable to find evidence that minimum staffing ratios for hemodialysis facilities are associated with improved patient outcomes. Our findings highlight the need for future work, studying the impact of these regulations at the facility level.

Brachiocephalic and Radiocephalic Arteriovenous Fistulas in Patients with Tunneled Dialysis Catheters Have Similar Outcomes

BACKGROUND

Patients with tunneled dialysis catheters (TDCs) have a time-sensitive need for a functional permanent access due to high risk of catheter-associated morbidity. Brachiocephalic arteriovenous fistulas (BCF) have been reported to have higher maturation and patency compared to radiocephalic arteriovenous fistulas (RCF), although more distal creation is encouraged when possible. However, this may lead to a delay in establishing permanent vascular access and, ultimately, TDC removal. Our goal was to assess short-term outcomes after BCF and RCF creation for patients with concurrent TDCs to see if these patients would potentially benefit more from an initial brachiocephalic access to minimize TDC dependence.

METHODS

The Vascular Quality Initiative hemodialysis registry was analyzed from 2011 to 2018. Patient demographics, comorbidities, access type, and short-term outcomes including occlusion, reinterventions, and access being used for dialysis, were assessed.

RESULTS

There were 2,359 patients with TDC, of whom 1,389 (58.9%) underwent BCF creation and 970 (41.1%) underwent RCF creation. Average patient age was 59 years, and 62.8% were male. Compared with RCF, those with BCF were more often older, of female sex, obese, nonindependently ambulatory, have commercial insurance, diabetes, coronary artery disease, chronic obstructive pulmonary disease, be on anticoagulation, and have a cephalic vein diameter of ≥3 mm (all P < 0.05). Kaplan-Meier analysis for 1-year outcomes for BCF and RCF, respectively, showed that primary patency was 45% vs. 41.3% (P = 0.88), primary assisted patency was 86.7% vs. 86.9% (P = 0.64), freedom from reintervention was 51.1% vs. 46.3% (P = 0.44), and survival was 81.3% vs. 84.9% (P = 0.02). Multivariable analysis showed that BCF was comparable to RCF with respect to primary patency loss (hazard ratio [HR] 1.11, 95% confidence interval [CI] 0.91-1.36, P = 0.316), primary assisted patency loss (HR 1.11, 95% CI 0.72-1.29, P = 0.66), and reintervention (HR 1.01, 95% CI 0.81-1.27, P = 0.92). Access being used at 3 months was similar but trending towards RCF being used more often (odds ratio 0.7, 95% CI 0.49-1, P = 0.05).

CONCLUSIONS

BCFs do not have superior fistula maturation and patency compared to RCFs in patients with concurrent TDCs. Creation of radial access, when possible, does not prolong TDC dependence.

A Case Report of a Successful Attempt to Create a Hemodialysis Vascular Access in a Patient With Recurrent Failed Arteriovenous Fistulas

The majority of individuals undergoing hemodialysis for chronic renal insufficiency (CRI) require vascular access. The more appropriate and long-term accesses are arteriovenous fistulas (AVF). These accesses must be attempted to be salvaged even in the circumstances when they stop functioning. In this study, a case report of a 57-year-old female patient with CRI who presented with a failed brachioradial and brachiocephalic AVF in the left upper limb and who later underwent the creation of a new functional radio-cephalic AVF mid-arm on the same limb is presented.

Sex Disparities in Arteriovenous Fistula Maturation Outcomes

BACKGROUND

The end-stage kidney disease life-plan aims to individualize hemodialysis (HD) access selection in patients requiring renal replacement therapy. Paucity of data on risk factors for poor arteriovenous fistula (AVF) outcomes limits the ability of physicians to guide their patients on this decision. This is especially true for female patients, who are known to have worse AVF outcomes when compared to male patients. The goal of this study was to identify risk factors associated with poor AVF maturation outcomes in female patients that will help guide individualized access selection.

METHODS

A retrospective review of 1,077 patients that had AVF creation between 2014 and 2021 at an academic medical center was performed. Maturation outcomes were compared between 596 male and 481 female patients. Separate multivariate logistic regression models were created for the male and female cohorts to identify factors associated with unassisted maturation. AVF was considered mature if it was successfully used for HD for 4-week sessions without need for further interventions. Unassisted fistula was defined as an AVF that matured without any interventions.

RESULTS

The male patients were more likely to receive more distal HD access; 378 (63%) male versus 244 (51%) female patients had radiocephalic AVF, P < 0.001. Maturation outcomes were significantly worse in female patients; 387 (80%) AVFs matured in females and 519 (87%) in male patients, P < 0.001. Similarly, the rate of unassisted maturation was 26% (125) in female patients versus 39% (233) in male patients, P < 0.001. Mean preoperative vein diameters were similar in both groups; 2.8 ± 1.1 mm in male versus 2.7 ± 0.97 mm in female patients, P = 0.17. Multivariate logistic regression analysis of the female patients revealed that Black race (odds ratio [OR]: 0.6, 95% confidence interval [CI]: 0.4-0.9, P = 0.045), radiocephalic AVF (OR: 0.6, 95% CI: 0.4-0.9, P = 0.045), and preoperative vein diameter <2.5 mm (OR: 1.4, 95% CI: 10.33-0.901.1-1.7, P = 0.014) were independent predictors of poor unassisted maturation in this cohort. In male patients, preoperative vein diameter <2.5 mm (OR: 1.4, 95% CI: 1.2-1.7, P < 0.001) and need for HD prior to AVF creation (OR: 0.6, 95% CI: 0.3-0.9, P = 0.018) were independent predictors of poor unassisted maturation.

CONCLUSIONS

Black women with marginal forearm veins may have worse maturation outcomes, and upper arm HD access should be considered when advising patients on their end-stage kidney disease life-plan.

Preoperative assessment for vascular access: Vascular mapping and handgrip strength

BACKGROUND

Reliable vascular access (VA) is required for patients receiving chronic hemodialysis (HD) treatment. Vascular mapping using duplex doppler ultrasonography (DUS) can aid in planning VA construction. Greater handgrip strength (HGS) was found to be associated with more developed distal vessels both in chronic kidney disease (CKD) patients and healthy individuals, and patients with lower HGS had worse morphologic vessel characteristics and were, therefore, less likely to construct distal VA.

OBJECTIVES

This study aims to describe and analyze clinical, anthropometric, and laboratory characteristics of patients who underwent vascular mapping prior to VA creation.

RESEARCH DESIGN

Prospective analysis.

SUBJECTS

Adult patients with CKD referred for vascular mapping, at a tertiary center, between March 2021 and August 2021.

MEASURES

Preoperative DUS by a single experienced nephrologist was carried out. HGS was measured using a hand dynamometer, and PAD was defined as ABI < 0.9. Sub-groups were analyzed according to distal vasculature size (<2 mm).

RESULTS

A total of 80 patients were included, with a mean age of 65.7 ± 14.7 years; 67.5% were male, and 51.3% were on renal replacement therapy (RRT). Twelve (15%) participants had PAD. HGS was higher in the dominant arm (20.5 ± 12.0 vs 18.8 ± 11.2 kg). Fifty-eight (72.5%) patients had vessels smaller than 2 mm in diameter. There were no significant differences between groups concerning demographics or comorbidities (diabetes, HTN, PAD). HGS was significantly higher in patients with distal vasculature greater than or equal to 2 mm in diameter (dominant arm: 26.1 ± 15.5 vs 18.4 ± 9.7 kg, p = 0.010; non-dominant arm: 24.1 ± 15.3 vs 16.8 ± 8.6, p = 0.008).

CONCLUSIONS

Higher HGS was associated with more developed distal cephalic vein and radial artery. Low HGS might be an indirect sign of suboptimal vascular characteristics, which might help predict the outcomes of VA creation and maturation.

Evaluating national guideline concordance of recurrent interventions after radiocephalic arteriovenous fistula creation

OBJECTIVE

Radiocephalic arteriovenous fistulas have been historically perceived as requiring multiple follow-up procedural interventions to achieve maturation and maintain patency. Recent clinical practice guidelines from the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) emphasize a patient-centered hemodialysis access strategy with new maximum targets for intervention rates, potentially conflicting with concomitant recommendations to prioritize autogenous forearm hemodialysis access creation. The present descriptive study seeks to assess whether radiocephalic fistulas can meet the KDOQI guideline benchmarks for interventions following access creation, and to elucidate clinical and anatomic characteristics associated with the timing and frequency of interventions following radiocephalic arteriovenous fistula creation.

METHODS

Prospective patient-level data from the multicenter PATENCY-1 and PATENCY-2 randomized trials, which enrolled patients undergoing new radiocephalic arteriovenous fistula creation, was analyzed (ClinicalTrials.govNCT02110901 and NCT02414841). The primary outcome was the rate of interventions at 1 year postoperatively. Incidence rates were calculated, and time to surgical or endovascular intervention following fistula creation was modeled using recurrent event extensions of the Cox proportional hazards model. Confidence intervals at the 95% level were calculated using nonparametric bootstrapping.

RESULTS

The cohort consisted of 914 patients; mean age was 57 years (standard deviation, 13 years), and 22% were female. Median follow-up was 707 days (interquartile range, 447-1066 days). The incidence of interventions per person-year was 1.04 (95% confidence interval [CI], 0.95-1.13) overall; 1.10 (95% CI, 0.98-1.21) before fistula use, and 0.96 (95% CI, 0.82-1.11) after fistula use. The most common interventions overall were balloon angioplasty (54.9% of all interventions), venous side-branch ligation (16.4%), and open revisions (eg, proximalization from snuffbox to wrist, 16.4%). The locations requiring balloon angioplasty included the juxta-anastomotic segment (51.7% of angioplasties), the outflow vein (29.2%), the inflow artery (14.8%), the central veins (3.8%), and the cephalic arch (0.5%). Common indications were to restore or maintain patency (75.6% of all interventions), assist maturation (14.9%), improve depth (4.4%), or improve augmentation (3.0%). In the multivariable regression analysis, female sex (adjusted hazard ratio [HR], 1.21; 95% CI, 1.05-1.45), diabetes (HR, 1.21; 95% CI, 1.01-1.46), and intraoperative vein diameter <3.0 mm (vs ≥4.0 mm: HR, 1.33; 95% CI, 1.02-1.66) were associated with earlier and more frequent interventions. Patients not on hemodialysis at the time of fistula creation underwent less frequent interventions (HR, 0.69; 95% CI, 0.59-0.81).

CONCLUSIONS

Patients with radiocephalic arteriovenous fistulas can expect to undergo one intervention, on average, in the first year after creation, which aligns with current KDOQI guidelines. Patients already requiring hemodialysis, female patients, patients with diabetes, and patients with intraoperative vein diameters <3.0 mm were at increased risk for repeated intervention. No subgroup exceeded guideline-suggested maximum thresholds for recurrent interventions. Overall, the results demonstrate that creation of radiocephalic arteriovenous fistula remains a guideline-concordant strategy when part of an end-stage kidney disease life-plan in appropriately selected patients.

CMS ESRD quality incentive program has not improved patient dialysis vascular access

PURPOSE

Over 468,000 patients in the United States use hemodialysis to manage End Stage Renal Disease (ESRD). The purpose of this study was to determine whether the dialysis access Clinical Performance Measures (CPMs) of Centers for Medicare & Medicaid Services (CMS) ESRD Quality Incentive Program (QIP) have increased arteriovenous fistula (AVF) rates and decreased long-term tunneled hemodialysis catheter (TDC) rates among hemodialysis patients in United States.

METHODS

Retrospective observational study: evaluated reported AVF and long-term TDC rates of 4804 dialysis facilities which reported dialysis access data as part of the ESRD QIP from Payment Year (PY) 2014-2020. Facilities were also sorted by specific additional criteria to examine disparities in dialysis access.

RESULTS

Mean AVF rates of included facilities increased from 63.7% in PY 2014 to 67.2% in PY 2016 (p < 0.05), did not change in PY 2017 (p > 0.05), and declined significantly in PY 2018-2020 to 64.1% in PY 2020, near AVF rates at the inception of program. Long-term TDC rates decreased from 10.4% in PY 2014 to 9.88% in PY 2015 (p < 0.05), then increased in PY 2015-PY 2020 to rates higher than at the inception of program, at 11.8% in PY 2020 (p < 0.05). Facilities serving majority Black ZIP Code Tabulation Areas (ZCTAs) or ZCTAs with median income <$45,000 achieved significantly lower AVF rates (p < 0.05) with no significant difference in long-term TDC rates (p > 0.05). AVF rates correlated positively and long-term TDC rates correlated negatively with star rating of facilities (p < 0.05).

CONCLUSION

As one of the first financial QIPs in healthcare, the ESRD QIP has not achieved the stated goals of the CMS to increase AVF access rates above 68% and reduce long-term TDC clinical rates below 10%. Systemic disparities in race, geographic region, economic status, healthcare access, and education of providers and patients prevent successful attainment of goal metrics.

The challenging surgical vascular access creation

With the increasing life expectancy of patients with end-stage kidney disease, the creation and maintenance of hemodialysis vascular access are becoming more challenging. A comprehensive patient evaluation including a complete history, physical examination, and ultrasonographic vessel assessment is the foundation of the clinical evaluation. A patient-centered approach acknowledges the myriad of factors that impact the selection of optimal access for the distinct clinical and social circumstance of each patient. An interdisciplinary team approach involving various healthcare providers in all stages of hemodialysis access creation is important and associated with better outcomes. While patency is considered the most important parameter in most vascular reconstructive scenarios, the ultimate determinant of success in vascular access for hemodialysis is a circuit that allows consistent and uninterrupted delivery of the prescribed hemodialysis. The best conduit is one that is superficial, easily identified, straight, and of a large caliber. Individual patient factors and skill level of the cannulating technician also play a crucial role in the initial success and maintenance of vascular access. Special attention should be considered in dealing with more challenging groups such as the elderly population where the newest vascular access guidance from The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative will be transformative. The current guidelines recommend monitoring the vascular access by regular physical and clinical assessments, however, inadequate evidence is available to support routine ultrasonographic surveillance for improving access patency.

Tunneled central venous catheters for hemodialysis-unfairly condemned? Catheter-related complications in a university hospital setting

BACKGROUND

Central venous catheters (CVCs) provide an immediate hemodialysis access but are considered to be of elevated risk for complications. It remains unclear, if CVCs per se have relevant impact on clinical outcome. We provide an assessment of CVC-associated complications and their impact on mortality.

METHODS

In a single center retrospective study, CVC patients between JAN2015-JUN2021 were included. Data on duration of CVC use, complications and comorbidities was collected. Estimated 6-month mortality was compared to actual death rate.

RESULTS

About 478 CVCs were analyzed. Initiation of dialysis was the main reason for CVC implantation. Death was predominant for termination of CVC use. Infections were rare (0.6/1000 catheter days), complications were associated with certain comorbidities. Actual 6-month mortality was lower than predicted (14.3% vs 19.6%).

CONCLUSION

(1) CVCs are predominantly implanted for initiation of hemodialysis; (2) serious complications are rare; (3) complications are associated with certain comorbidities; and (4) CVC patients survive longer than predicted.

A Retrospective Review of Bovine Artery Graft Patency: A Single Site Study

BACKGROUND

The hemodialysis dependent population is increasing in the United States. Dialysis access complications are a significant source of morbidity and mortality for patients with end stage renal disease (ESRD). A surgically created autogenous arteriovenous fistula (AVF) has been the gold standard for dialysis access. However, for patients who are not candidates for AVF, arteriovenous grafts using various conduits have widely been utilized. In this study, we report the outcomes of bovine carotid artery (BCA) grafts for dialysis access at a single institution, and compare these results to those for polytetrafluoroethylene (PTFE) grafts.

METHODS

A single-institution, retrospective review of all patients undergoing surgical placement of a bovine carotid artery graft for dialysis access from 2017-2018 was performed under an IRB-approved protocol. The primary, primary-assisted, and secondary patency were calculated for the whole cohort and results determined based on gender, BMI and indication for use. Comparison was performed to PTFE grafts at same institution from 2013 to 2016.

RESULTS

One hundred and twenty two patients were included in this study. Seventy-four patients had a BCA graft placed while 48 had a PTFE graft placed. . The mean age was 59.7±13.5 years in the BCA group, 55.8±14.5 in the PTFE group and the mean BMI was 29.8 ± 9.2 kg/m² in the BCA group and 28.1±9.7 in the PTFE group. Comparison of the comorbidities present in BCA/PTFE groups included hypertension (92%/100%), diabetes (57%/54%), congestive heart failure (28%/10%), lupus (5%/7%), and chronic obstructive pulmonary disease (4%/8%). The various configurations were reviewed (BCA/PTFE): interposition/access salvage (40.5%/13%), axillary-axillary (18.9%/7%), brachial-basilic (5.4%,6%), brachial-brachial (4.1%,4%), brachial-cephalic (1.4%0%), axillary-brachial (1.4%/0%), brachial-axillary (23%, 62%), and femoral-femoral (5.4%,6%). Overall, twelve-month primary patency was 50% in the BCA group and 18% in the PTFE group (p=0.001). Twelve-month primary-assisted patency was 66% in the BCA group and 37% in the PTFE group (p=0.003). Twelve-month secondary patency was 81% in the BCA group and 36% in the PTFE group (p=0.07). When comparing BCA graft survival probability among male and female gender, males had better primary-assisted patency (p = 0.042). Secondary patency among the two genders was similar. There was no statistically significant difference in primary, primary-assisted and secondary patency of BCA grafts between different BMI groups or indication for use. The average patency of a bovine graft was 17.8 ±8 months. Sixty-one percent of the BCA grafts needed intervention with 24% needing multiple interventions. There was an average of 7 ±5 months to first intervention. The infection rate was 8.1% in the BCA group and 10.4% in the PTFE group with no statistical difference.

CONCLUSION

Primary and primary-assisted patency rates at 12 months in our study were higher than those for PTFE at our institution. There was higher primary assisted patency of BCA grafts among males at 12 months compared to PTFE. Obesity and indication for BCA graft use did not appear to affect patency in our population.

Biomimetic cardiac tissue chip and murine arteriovenous fistula models for recapitulating clinically relevant cardiac remodeling under volume overload conditions

Cardiovascular events are the primary cause of death among dialysis patients. While arteriovenous fistulas (AVFs) are the access of choice for hemodialysis patients, AVF creation can lead to a volume overload (VO) state in the heart. We developed a three-dimensional (3D) cardiac tissue chip (CTC) with tunable pressure and stretch to model the acute hemodynamic changes associated with AVF creation to complement our murine AVF model of VO. In this study, we aimed to replicate the hemodynamics of murine AVF models in vitro and hypothesized that if 3D cardiac tissue constructs were subjected to "volume overload" conditions, they would display fibrosis and key gene expression changes seen in AVF mice. Mice underwent either an AVF or sham procedure and were sacrificed at 28 days. Cardiac tissue constructs composed of h9c2 rat cardiac myoblasts and normal adult human dermal fibroblasts in hydrogel were seeded into devices and exposed to 100 mg/10 mmHg pressure (0.4 s/0.6 s) at 1 Hz for 96 h. Controls were exposed to "normal" stretch and experimental group exposed to "volume overload". RT-PCR and histology were performed on the tissue constructs and mice left ventricles (LVs), and transcriptomics of mice LVs were also performed. Our tissue constructs and mice LV both demonstrated cardiac fibrosis as compared to control tissue constructs and sham-operated mice, respectively. Gene expression studies in our tissue constructs and mice LV demonstrated increased expression of genes associated with extracellular matrix production, oxidative stress, inflammation, and fibrosis in the VO conditions vs. control conditions. Our transcriptomics studies demonstrated activated upstream regulators related to fibrosis, inflammation, and oxidative stress such as collagen type 1 complex, TGFB1, CCR2, and VEGFA and inactivated regulators related to mitochondrial biogenesis in LV from mice AVF. In summary, our CTC model yields similar fibrosis-related histology and gene expression profiles as our murine AVF model. Thus, the CTC could potentially play a critical role in understanding cardiac pathobiology of VO states similar to what is present after AVF creation and may prove useful in evaluating therapies.

One-Year Mortality after Hemodialysis Initiation: The Prognostic Role of the CHA2DS2-VASc Score

BACKGROUND

CKD is a significant cause of morbidity, cardiovascular and all-cause mortality. CHA2DS2-VASc is a score used in patients with atrial fibrillation to predict thromboembolic risk; it also appears to be useful to predict mortality risk. The aim of the study was to evaluate CHA2DS2-VASc scores as a tool for predicting one-year mortality after hemodialysis is started and for identifying factors associated with higher mortality.

METHODS

Retrospective analysis of patients who started hemodialysis between January 2014 and December 2019 in Centro Hospitalar Universitário Lisboa Norte. We evaluated mortality within one year of hemodialysis initiation. The CHA2DS2-VASc score was calculated at the start of hemodialysis.

RESULTS

Of 856 patients analyzed, their mean age was 68.3 ± 15.5 years and the majority were male (61.1%) and Caucasian (84.5%). Mortality within one-year after starting hemodialysis was 17.8% (n = 152). The CHA2DS2-VASc score was significantly higher (4.4 ± 1.7 vs. 3.5 ± 1.8, p < 0.001) in patients who died and satisfactorily predicted the one-year risk of mortality (AUC 0.646, 95% CI 0.6-0.7, p < 0.001), with a sensitivity of 71.7%, a specificity of 49.1%, a positive predictive value of 23.9% and a negative predictive value of 89.2%. In the multivariate analysis, CHA2DS2-VASc ≥3.5 (adjusted HR 2.24 95% CI (1.48-3.37), p < 0.001) and central venous catheter at dialysis initiation (adjusted HR 3.06 95% CI (1.93-4.85)) were significant predictors of one-year mortality.

CONCLUSION

A CHA2DS2-VASc score ≥3.5 and central venous catheter at hemodialysis initiation were predictors of one-year mortality, allowing for risk stratification in hemodialysis patients.

Intraoperative vascular mapping improves patient eligibility for arteriovenous fistula creation

BACKGROUND

We assessed the utility of intraoperative vein mapping performed by the operating surgeon for evaluating vessel suitability for arteriovenous fistula (AVF) creation.

METHODS

In a retrospective review of 222 AVFs, vein diameter measurements were compared between intraoperative and preoperative mapping in the same anatomical location. AVF creation was based on intraoperative vein diameter ≥2 mm, using a distal to proximal and superficial veins first approach. Potential selection of access type based on preoperative findings alone was analyzed.

RESULTS

The mean diameter of the veins used for AVF creation measured 3.6 ± 0.8 mm on intraoperative duplex versus 2.5 ± 0.9 mm when the same veins were measured on preoperative duplex. Based on preoperative mapping alone, 23% of patients would have received a more proximal AVF and 5% would have needed a graft. AVFs created more distally based on intraoperative findings had similar maturation rates compared to the rest of the cohort, 79% versus 84% (p = 0.2).

CONCLUSIONS

Intraoperative vein mapping can be used to evaluate vessel suitability for AVF and compared to pre-operative vein mapping may increase the eligibility of distal veins for fistula creation while reducing the need for AV grafts.

The evolving panorama of vascular access in the 21st century

There are three major types of hemodialysis vascular access: hemodialysis catheters, arteriovenous grafts, and arteriovenous fistulas. Arteriovenous fistulas provide the best access due to their reliability and long-term patency. They are recommended by the current Kidney Disease Outcomes Quality Initiatives (K-DOQI) guidelines; however, not all patients benefit from arteriovenous fistulas due to poor maturation or a lack of adequate vasculature. Currently, hemodialysis is initiated via catheters in the majority of patients. Catheters are associated with high morbidity and mortality due to infection, lower quality of dialysis, and the development of central vein stenosis. The varied responses of patients to the different access types exemplify the need to choose the "right access for the right patient" based on scores that can predict death risk and progression of chronic kidney disease. Additionally, vascular access, often referred to as the "Achilles' heel" of hemodialysis patients, represents a significant percentage of the Medicare budget that continues to increase yearly. The purpose of this paper is to review the current literature on the management of vascular access complications and infection treatment and prevention. The paper also explores emerging research regarding the devices and methods to improve access outcomes such as early cannulation arteriovenous grafts, endovascular arteriovenous fistula creation, and regenerative grafts with resorbable scaffolds, among others. The data were collected through literature searches via PubMed, Athens and web search engines.

Outcomes after Elective Abdominal Aortic Aneurysm Repair Have Improved Over Time in Patients on Dialysis

BACKGROUND

Prior studies have demonstrated poor perioperative and long-term survival of patients with end-stage kidney disease (ESKD) on dialysis who undergo abdominal aortic aneurysm repair (AAAR). However, survival in dialysis patients overall has improved over time. We hypothesize that the contemporary rates of perioperative and long-term survival following AAAR in ESKD patients are also improving.

METHODS

Data on AAAR procedures in dialysis patients were collected from the United States Renal Data System between 2008 and 2017. Endovascular (EVAR) and open AAA repair (OAR) were identified by Current Procedural Terminology codes. Patients with a functioning renal transplant, a ruptured aneurysm, and insurance other than Medicare were excluded. Demographics, comorbidities, procedural details, and long-term outcomes were collected. Standard statistical methods were used.

RESULTS

We identified 3,374 patients who underwent EVAR (86%, 2,914/3,374) and OAR (14%, 460/3,374). The utilization of OAR decreased significantly from 2008 to 2017 (17.34% vs. 7.43%, P < 0.001). Kaplan-Meier survival analysis revealed no significant difference in 5-year survival between OAR and EVAR (24% vs. 17%, P = 0.1, Wilcoxon-Breslow test), but open repair was associated with increased long-term survival (Hazards ratio 0.994, confidence interval 0.990-0.999, P = 0.017) in an adjusted Cox regression model. The cohort was then divided based on the year of AAAR, group 1: 2008-2010 (1,269/3,374), group 2: 2011-2013 (1,071/3,374), and group 3: 2014-2017 (1,034/3,374). Compared to groups 1 and 2, Group 3 was less likely to have coronary artery device, peripheral vascular disease, recent pneumonia, be nonambulatory, live in a nursing facility, or undergo an OAR and more likely to be younger and dialyze through an arteriovenous fistula/arteriovenous graft at the time of AAA repair. Thirty-day postoperative mortality was significantly lower in group 3 compared to groups 1 and 2 (5.4% [56/1,034] vs. 10.3% [131/1,269]/7.3% [78/1,071], P < 0.031). One-year survival by Kaplan-Meier estimate was significantly higher in group 3 (77.7% [803/1,034]) versus groups 1 and 2 (56.7% [719/1,269], 66.9% [716/1,071], P < 0.001, log-rank test). Five-year survival was also significantly higher in group 3 (27.3%) compared to groups 1 and 2 (14.2% and 16.5%, P < 0.001, log-rank test). In a Cox regression model of long-term mortality adjusted for variables significant on a univariate testing, more recent procedure year was associated with increased survival (Hazards ratio 0.81, [0.77, 0.85], P < 0.001).

CONCLUSIONS

Postoperative and long-term survival following AAA repair have increased over time in ESKD patients on dialysis. This increased survival persists after accounting for differences in patient demographics and type of procedure over time. Elective AAA repair should be considered in carefully selected good-risk patients on dialysis.

Evolutive profile of hemodialysis vascular accesses Hemodialysis accesses

INTRODUCTION

Arterio-venous fistula (AVF) is the first-choice vascular access for hemodialysis (HD). Hemodialysis catheter (KT) may be a temporary or permanent alternative.

AIM

To evaluate indications of KT and AVF and their predictive factors of complications.

METHODS

It's a retrospective multicentric study interesting KT and AVF in patients treated by hemodialysis, in the Kef Governorate in north-western Tunisia, during the period from 01/07/18 to 31/12/18.

RESULTS

We included 288 AVF and 148 KT that were created on 205 patients. The average age was 58.14 years, the sex ratio was 1.5. Hypertensive patients and diabetics represented respectively 83.9% and 27.3% of the population. Diabetic nephropathy was the most common (25.9%). For the KT, the main indication was the wait for AVF creation (68.9%). The overall incidence of immediate complications was 11.5%. Dysfunction was reported in 23.6% of cases with obesity and tunneled type of KT as contributing factors. KT infection was occuring in 39.2% of cases. It was promoted by prolonged duration of use and hemoglobin level < 8g/dl. The use of antiseptic lock reduced infections' risk (p=0.011). For AVF, the most common complications were thrombosis (36.2%), aneurysm (29.9%) and stenosis (22.6%). Survival rate was 60% at 2000 days. The AVF impairing factors were diabetes (p=0.05), obesity (p=0.05), anterior AVF creation (p=0.011), AVF grafts (p=0.016), and anticoagulant therapy (p=0.0001). Antiplatelet therapy improved AVF patency (p=0.02).

CONCLUSION

Much remained to be done to reduce KT complications, creation of AVF on time and prevention of their complications.

Staphylococcus aureus Bacteremia Among Patients Receiving Maintenance Hemodialysis: Trends in Clinical Characteristics and Outcomes

RATIONALE & OBJECTIVE

Staphylococcus aureus (Saureus) bacteremia (SAB) is associated with morbidity and mortality in patients receiving maintenance hemodialysis (HD). We evaluated changes in clinical and bacterial characteristics, and their associations with clinical outcomes with SAB in this population over a 21-year period.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

453 hospitalized, non-neutropenic adults receiving maintenance HD who developed monomicrobial SAB between 1995 and 2015.

EXPOSURE

Clinical characteristics and bacterial genotype.

OUTCOME

All-cause and SAB-attributable mortality, persistent bacteremia, and metastatic complications.

ANALYTICAL APPROACH

Proportions of participants experiencing each outcome were calculated overall and by calendar year. Secular trends were estimated using binomial risk regression, a generalized linear model with the log link function for a binomial outcome. Associations with outcomes were estimated using logistic regression.

RESULTS

Over the 21-year study period, patients receiving maintenance HD experienced significant increases in age- and diabetes-adjusted SAB-attributable mortality (0.45% [95% CI, 0.36%-0.46%] per year), persistent bacteremia (0.86% [95% CI, 0.14%-1.55%] per year), metastatic complications (0.84% [95% CI, 0.11%-1.56%] per year), and infection with the virulent Saureus clone USA300 (1.47% [95% CI, 0.33%-2.52%] per year). Over time, the suspected source of SAB was less likely to be a central venous catheter (-1.32% [95% CI, -2.05 to-0.56%] per year) or arteriovenous graft (-1.08% [95% CI, -1.54 to-0.56] per year), and more likely to be a nonvascular access source (1.89% [95% CI, 1.29%-2.43%] per year). Patients with a nonvascular access suspected source of infection were more likely to die as a result of their S aureus infection (OR, 3.20 [95% CI, 1.36-7.55]). The increase in USA300 infections may have contributed to the observed increase in persistent bacteremia (OR, 2.96 [95% CI, 1.12-7.83]) but did not explain the observed increases in SAB-attributable mortality (OR, 0.83 [95% CI, 0.19-3.61]) or metastatic complications (OR, 1.34 [95% CI, 0.53-3.41]).

LIMITATIONS

Single-center, inpatient cohort.

CONCLUSIONS

The clinical and molecular epidemiology of SAB in patients receiving maintenance HD has changed over time, with an increase in SAB-attributable mortality and morbidity despite a decline in catheter-related infections.

Bridge of Tunneled Cuffed Catheter as a Risk for Future Arteriovenous Fistulae Failure

Background: A clinically tunneled cuffed catheter (TCC) for hemodialysis (HD) is often inserted into end-stage renal disease patients, who have an immature or no arteriovenous fistula (AVF), for the performance of HD to relieve uremic syndrome or to solve uncontrolled fluid overload, hyperkalemia, or metabolic acidosis. The catheter is primarily regarded as a bridge until the AVF matures and can be cannulated for HD. However, the effect of the bridge of the TCC on the future patency of AVFs remains elusive. Methods: This nationwide population-based observational study compared the hazards of AVF failure and the time to AVF failure. We enrolled 24,142 adult incident patients on HD, who received HD via AVFs for at least 90 days between 1 January 2010 and 31 December 2015. The subjects were divided into two groups, according to the history of TCC, and were followed-up until the failure of the AVF, mortality, or the end of the study. A propensity score-matched analysis based on 1:1 matching of age, sex, and baseline comorbidities was utilized to reduce bias and confounding variables. Results: A Kaplan−Meier survival curve revealed that patients with and without a history of TCC had significantly better AVF survival rates (log-rank test; p < 0.001). A history of TCC was independently associated with a higher risk of new AVF or AVG creation due to AVF failure, after the adjustment of the Charlson comorbidity index score (corresponding adjusted hazard ratios of 2.17 and 1.52; 95% confidence intervals of 1.77−2.67 and 1.15−1.99). For the impact of time on AVF failure, patients with a TCC bridge had a significantly higher incidence of new AVF creation during the first year after the AVF cannulation. Conclusion: A history of a TCC bridge was an independent risk factor for AVF failure and the time of AVF failure was significantly higher during the first year after the fistula cannulation in the TCC bridge group.

The association between the locations of arteriovenous fistulas and patency rates: A systematic review and meta-analysis

BACKGROUND

The arteriovenous fistulas (AVF) continue to be the most prevalent type of vascular access for hemodialysis (HD). However, the appropriate locations of AVF are controversial. We conducted the meta-analysis to investigate the differences in patency between upper-arm and forearm AVF.

METHODS

PubMed, EMBASE, CENTRAL, and ISI Web of Science were searched to identify studies with differences in AVF patency at different locations. Reviewers searched the database, screened studies according to inclusion criteria, and conducted Meta-analysis.

RESULTS

A total of 12 studies involving 3437 patients were selected. Pooled data showed that primary patency (PP) of AVF were higher in upper-arm than forearm at 1 and 2 years (odds ratio [OR] = 1.54, p = 0.0005; OR = 2.45, p = 0.001), but the differences in cumulative patency (CP) were not statistically significant at 1 and 2 years (OR = 2.10, p = 0.08; OR = 2.16, p = 0.1). The differences in PP and CP between upper-arm and forearm AVF in patients older than 65 years were not statistically significant at 1 (OR = 1.61, p = 0.05; OR = 2.05, p = 0.17) and 2 years (OR = 3.40, p = 0.13; OR = 1.38, p = 0.16). In Asian patients, the differences in PP and CP between upper-arm and forearm AVF were not statistically significant at 1 (OR = 1.17, p = 0.41; OR = 1.02, p = 0.94) and 2 years (OR = 2.95, p = 0.08; OR = 1.23, p = 0.41).

CONCLUSIONS

In this study, the CP of upper-arm and forearm AVF was similar in overall population. There was no difference in PP and CP of AVF between upper-arm and forearm in Asian population or the elderly. The forearm AVF could be consider to be the first choice. for Asian patients or the elderly.

Modified Banding of Arteriovenous Fistulas for the Treatment of Vascular Access Induced Digital Ischaemia

Objective

Vascular access induced digital ischaemia is an uncommon complication of haemodialysis access procedures and is difficult to manage. Several techniques have been described to treat this phenomenon, with variable long term success. Although all of these procedures have been shown to work, they have a significant failure rate, such as persistent high vascular access flow or loss of access. One of the major technical limitations of these techniques is the lack of quantitative data gathered during the procedure to ensure treatment success. In this study, the aim was to describe a novel technique that can improve the success of banding in preserving access and eliminating digital ischaemia.

Technique

A modified method for arteriovenous fistula banding that incorporates measurements of distal arterial pressure to improve the success of the procedure is described.

Results

Sixteen patients with vascular access induced digital ischaemia and high-flow vascular access were treated using the technique. All procedures were technically successful. At 30 days, complete symptomatic relief (clinical success) was seen in 81% (n = 13) of patients. There was no access thrombosis or infection in any of the patients at the 30 day follow up. Six month follow up data were available in seven patients. There was no loss of access patency or recurrence of symptoms observed at six months.

Conclusion

This novel technique is simple and effective and can be used safely as first line therapy for the management of vascular access induced digital ischaemia.

•

Modified banding of arteriovenous fistulas (AVF) is associated with no access thrombosis or infection.

•

Modified AVF banding leads to resolution of vascular access induced ischaemia in the majority of patients.

•

Modified AVF banding is a simple, minimally invasive, and effective technique.

Provision of Kidney Disease Education Service Is Associated with Improved Vascular Access Outcomes among US Incident Hemodialysis Patients

Background

Pre-ESKD Kidney Disease Education (KDE) has been shown to improve multiple CKD outcomes, but its effect on vascular access outcomes is not well studied. In 2010, Medicare launched KDE reimbursements policy for patients with advanced CKD.

Methods

In this retrospective USRDS analysis, we identified all adult patients on incident hemodialysis with ≥6 months of pre-ESKD Medicare coverage during the first 5 years of CMS-KDE policy and divided them into CMS-KDE services recipients (KDE cohort) and nonrecipients (non-KDE cohort). The primary outcome was incident arteriovenous fistula (AVF) and the composite of incident AVF or arteriovenous graft (AVG) utilization. Secondary outcomes were central venous catheter (CVC) with maturing AVF/AVG and pure CVC utilizations. Step-wise multivariate analyses were performed in four progressive models (model 1, KDE alone; model 2, multivariate model encompassing model 1 with sociodemographics; model 3, model 2 with comorbidity and functional status; and model 4, model 3 with pre-ESKD nephrology care).

Results

Of the 211,990 qualifying patients on incident hemodialysis during the study period, 2887 (1%) received KDE services before dialysis initiation. The rates of incident AVF and composite AVF/AVG were more than double (30% and 35%, respectively, compared with 14% and 17%), and pure catheter use about a third lower (40% compared with 65%) in the KDE cohort compared with the non-KDE cohort. The maximally adjusted odds ratios in model 4 for study outcomes were incident AVF use, 1.78, 99% confidence interval, 1.55 to 2.05; incident AVF/AVG use, 1.78, 99% confidence interval, 1.56 to 2.03; incident CVC with maturing AVF/AVG, 1.69, 99% confidence interval, 1.44 to 1.97; and pure CVC without any AVF/AVG, 0.51, 99% confidence interval, 0.45 to 0.58. The benefits of the KDE service were maintained even after accounting for the presence, duration, and facility of ESKD care.

Conclusion

The occurrence of pre-ESRD KDE service is associated with significantly improved incident vascular access outcomes. Targeted studies are needed to examine the effect of KDE on patient engagement and self-efficacy as a cause for improvement in vascular access outcomes.

Research Priorities for Percutaneous Arteriovenous Fistula Creation in Patients with End-Stage Renal Disease: Proceedings and Recommendations from a Multidisciplinary Research Consensus Panel

Recently developed endovascular techniques to create percutaneous arteriovenous fistulas are an alternative to surgical arteriovenous fistula creation, although there is currently a lack of high-level evidence regarding their creation, maturation, utilization, and long-term function. Recognizing this, the Society of Interventional Radiology Foundation sponsored a Research Consensus Panel and Summit for the prioritization of a research agenda to identify and address the gaps in current knowledge.

Ultrasound evaluation of access complications: Thrombosis, aneurysms, pseudoaneurysms and infections

Arteriovenous fistula (AVF) complications are classified based on fistula outcomes. This review aims to update colour Doppler (CD) and pulse wave Doppler (PWD) roles in managing early and late complications of the native and prosthetic AVF. Vascular access (VA) failure occurs because inflow or outflow stenosis activates Wirchow's triad inducing thrombosis. Therefore, the diagnosis of the tributary artery and outgoing vein stenosis will be the first topic considered. Post-implantation complications occur from the inability to achieve AVF maturation and dialysis suitability due to inflow/outflow stenosis. Late stenosis is usually a sequence of early defects repaired to maintain patency. Less frequently, in the mature AVF or graft, complications are acquired 'de novo'. They derive either from incorrect management of vascular access (haematoma, pseudoaneurysm, prosthesis infection) or wall pathologies (aneurysm, myxoid valve degeneration, kinking, coiling, abnormal dilation from defects of elastic structures). High-resolution transducers (10-20 MHz) allow the characterization of the wall damage, haemodynamic dysfunctions, early and late complications even if phlebography remains the gold standard for the diagnosis for its sensitivity and specificity.

Sex Differences in Inflammation During Venous Remodeling of Arteriovenous Fistulae

Vascular disorders frequently have differing clinical presentations among women and men. Sex differences exist in vascular access for hemodialysis; women have reduced rates of arteriovenous fistula (AVF) maturation as well as fistula utilization compared with men. Inflammation is increasingly implicated in both clinical studies and animal models as a potent mechanism driving AVF maturation, especially in vessel dilation and wall thickening, that allows venous remodeling to the fistula environment to support hemodialysis. Sex differences have long been recognized in arterial remodeling and diseases, with men having increased cardiovascular events compared with pre-menopausal women. Many of these arterial diseases are driven by inflammation that is similar to the inflammation during AVF maturation. Improved understanding of sex differences in inflammation during vascular remodeling may suggest sex-specific vascular therapies to improve AVF success.

Detecting the prevalence of bacterial colonization on tunneled cuffed hemodialysis catheters using quantitative PCR targeting 16S rRNA and scanning electron microscopy

BACKGROUND AND OBJECTIVES

Tunneled cuffed hemodialysis catheters (TCC) get colonized by microorganisms, increasing risk for catheter related bacteremia (CRB). Our objective was to detect the prevalence of bacterial colonization of TCC by using quantitative PCR (qPCR) targeting 16S rRNA and by determining the intraluminal adherent biological material (ABM) coverage.

METHODS

A total of 45 TCC were investigated. The 16S rRNA qPCR technique was used to detect bacterial colonization after scraping the intraluminal ABM. Proximal, middle, and distal TCC were evaluated by scanning electron microscopy (SEM) to determine the percentage (%) of intraluminal ABM coverage. All catheters were cultured following sonication.

RESULTS

A total of 45 TCC were removed: 7 due to CRB, 3 for suspected CRB and 35 were removed for non-infectious etiologies. Bacterial colonization was detected in 27 TCC by documenting 16S rRNA qPCR (+) results (60%). Seven of these 16S rRNA qPCR (+) catheters were removed due to CRB. There was no difference in demographic, clinical, or laboratory values between the 16S rRNA (+) versus (-) TCC. The 16S rRNA qPCR (-) outcome was highly associated with CRB-free status with negative predictive value of 100%. Bacterial colonization was documented in 10 TCC using catheter cultures (22%), which was significantly less compared to qPCR method (p = 0.0002). ABM were detected in all catheter pieces, with mean intraluminal surface coverage (ABMC) of 68.4 ± 26.1%. ABM was unlikely to be microbial biofilm in at least 36% of removed TCC as their 16S rRNA qPCR and catheter culture results were both negative.

CONCLUSIONS

Detecting bacterial colonization of TCC was significantly higher with 16S rRNA qPCR compared to catheter cultures. The 16S rRNA qPCR (-) cannot be predicted and was strongly associated with absence of CRB. Intraluminal ABM was not associated with microbial presence in about 1/3 of the TCC. These pieces of evidence may help to improve prophylactic strategies against CRB.

Is the Fistula First Approach still valid?

The Fistula First Breakthrough Initiative, founded in 2003, was responsible for changing the access profile in the United States, increasing the prevalence of arteriovenous fistulas (AVFs) by 50% and reducing that of arteriovenous grafts (AVGs). However, the concept that AVFs are always the best access for all patients has been challenged. Discussion points are: (1) the questionable survival benefit of AVFs over AVGs, if one takes into account the high rates of primary AVF failure; (2) the potential benefits of using AVGs for greater primary success; and (3) the questionable benefit of AVFs over AVGs in patients with shorter survival, such as the elderly. The high rate of primary failure and maturation procedures leads to prolonged use of catheters, and it is one of the weaknesses of the fistula first strategy. AVGs proved to be better than AVFs as a second access after the failure of a first AVF, and in patients with non-ideal vessels, with greater primary success and reduced catheter times. AVGs appear to have a similar survival to AVFs in patients older than 80 years, with less primary failures and interventions to promote maturation. The most recent KDOQUI guidelines suggest an individualized approach in access planning, taking into account life expectancy, comorbidities and individual vascular characteristics, with the aim of chosing adequate access for the right patient, at the right time, for the right reasons.

Predialysis nephrology care amongst Palestinian hemodialysis patients and its impact on initial vascular access type

Referral time for end-stage renal disease (ESRD) patients to nephrologists and initial vascular access method are considered significant factors that impact health outcomes at the time of hemodialysis (HD) initiation. Native arteriovenous fistula (AVF) is strongly recommended as initial access. However, little is known about the referral rate among ESRD receiving HD in Palestine and its correlation with AVF creation. In Ramallah Hemodialysis Center, we investigated the pre-dialysis nephrology care and AVF usage in 156 patients. Type of access at HD initiation was temporary central venous catheter (CVC) in 114 (73%), tunneled hemodialysis catheter (TDC) in 21 (13%) and AVF in 21 (13%). Out of all participants, 120 (77%) were seen by nephrologist prior to dialysis. Of the participants who initiated dialysis with a CVC, 36 (31%) had not received prior nephrology care. All participants who initiated dialysis with functional AVF had received prior nephrology care. Patients who were not seen by a nephrologist prior to HD initiation had no chance at starting HD with AVF, whereas 17% of those who had nephrology care >12 months started with AVF. In conclusion, a relatively large percentage of Palestinian HD patients who were maintained on HD did not have any predialysis nephrology care. In addition, patients who received predialysis nephrology care were significantly more likely to start their HD through AVF whereas all those without predialysis nephrology care started through CVC. More in-depth national studies focusing on improving nephrology referral in ESRD patients are needed to increase AVF utilization.

Natural Vascular Scaffolding Treatment Promotes Outward Remodeling During Arteriovenous Fistula Development in Rats

Following creation, an arteriovenous fistula (AVF) must mature (i.e., enlarge lumen to allow high blood flow) before being used for hemodialysis. AVF maturation failure rates are high, and currently, there are no effective therapy to treat this problem. The maturation process is likely affected by the integrity of the vascular extracellular matrix (ECM). Natural Vascular Scaffolding (NVS) Therapy is a new technology that interlinks collagen and elastin via photoactivation of a locally delivered small molecule (4-amino-1,8-naphtalamide). We hypothesized that NVS Therapy may improve AVF remodeling by preserving ECM integrity. AVFs were created in Wistar male rats by connecting the femoral vein (end) to femoral artery (side) in the same limb. Immediately after blood flow was restored to dilate the femoral vein by arterial pressure, a 10 μl-drop of the NVS compound (2 mg/ml) was placed on the anastomosis perivascularly. Following 5-min incubation, the NVS treated area was exposed to 1-min illumination by 450-nm light. The control group received 10 μl-drop of phosphate buffered saline (PBS) and the same light activation. The skin was closed, and rats were euthanized 4 weeks (n = 6-9 per group) post-AVF creation for histology, morphometry, immunohistochemistry (IHC), and multiphoton microscopy for second-harmonic-generation evaluation of collagen fibers. The vascular thickness was similar in both groups. The AVF vein's open lumen area and % open lumen area in NVS-treated rats were significantly larger than in PBS-treated rats (4.2-fold p = 0.014 and 2-fold p = 0.009, respectively). The inflammatory markers IL-6 and MMP-9 in the AVF walls were significantly decreased in the NVS group than the PBS group. Collagen fibers in the vascular wall trended toward perpendicular alignment to the lumen circumference in the NVS-treated AVFs, with more defined shape but less area than in the PBS-treated AVFs. These results indicate that the NVS Therapy exerted changes in collagen, which may influence AVF maturation. Rats tolerated the NVS treatment well, and the lack of cell death by the treatment was confirmed in cell culture experiments. These results suggest that NVS treatment is safe and may have therapeutic potential by facilitating lumen expansion to enhanced AVF maturation in patients.

Substitution of citrate with tissue plasminogen activator (rt-PA) for catheter lock does not improve patency of tunnelled haemodialysis catheters in a randomised trial

Backround

The study aim was to establish if substitution of citrate with rt-PA for catheter lock once weekly can reduce the incidence of catheter-related blood stream infections (CR-BSI) or improve patency of tunneled haemodialysis catheters.

Methods

All incident patients undergoing insertion of a tunneled haemodialysis catheter were screened and included except those suffering infection or using oral anticoagulation. Study participants were randomized into two arms according to the solution applied as catheter lock: receiving either trisodium citrate (Citra-LockTM 4%) only or rt-PA (Actilyse® 1 mg/ml) on the middle session each week with citrate used on the first and third sessions. The incidence of CR-BSI (confirmed by positive blood culture), catheter non-function (complete obstruction), and malfunction (blood flow < 250 ml/min) was recorded. Statistical significance was tested with ANOVA, post hoc analysis was performed by means of multiple linear regression.

Results

Totally, 18 patients were included and followed during 655 haemodialysis sessions. No episode of CR-BSI was detected while 6 catheter non-functions (0.9% sessions) and 101 malfunctions (15.4% sessions) were recorded. The incidence of both events was equal between the study arms: 4 non-functions and 55 malfunctions in the rt-PA arm and 2 non-functions and 46 malfunctions in the citrate arm (p = 0.47 and p = 0.24, respectively). Additionally, the mean blood flow achieved did not differ significantly between the arms: 326 ± 1,8 and 326 ± 1,9 ml/min (p = 0.95) in rt-PA and citrate arms, respectively. Post hoc analysis identified time elapsed since previous session (β = 0.12, p = 0.005) and malfunction on previous session (β = 0.25, p < 0.001) as significant factors affecting the occurrence of malfunction. By contrast, the study arm, rt-PA application on previous session, and catheter vintage did not enter the model.

Conclusion

Substitution of citrate with rt-PA for catheter lock does not reduce the incidence of catheter malfunction neither does it affect the blood flow achieved during haemodialysis. Catheter patency is related rather to the time interval between sessions and to previous malfunction (thus probably reflecting undefined individual factors). The incidence of CR-BSI within pre-selected haemodialysis population is sporadic (less than 1 per 4.3 patient years in our sample).

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12612000152820. Retrospectively registered 03/02/2012.

Inferiority of arteriovenous grafts, in comparison to autogenous fistulas, is underestimated by standard survival measures alone

BACKGROUND

It has been argued that a prosthetic arteriovenous graft (AVG) is a reasonable alternative to an arteriovenous fistula (AVF) for dialysis. We aimed to compare the patency rates and requirements for the intervention of newly formed AVF and AVG.

METHODS

A retrospective analysis was undertaken of AVF and AVG formed between 1 January 2013 and 31 December 2015 at two tertiary referral centres and followed up until 31 December 2017. Outcome measures included successful use for dialysis, patency rates and the number of interventions required to maintain dialysis access per patient-year (PPY).

RESULTS

Four hundred and seventy AVF and 92 AVG were constructed. Of 470 AVF, 324 (68.9%) were used compared to 80 of 92 (87%) AVG. One year assisted primary patency of AVF was 75% (confidence interval 71-79%) compared to 47% (confidence interval 36-57%) for AVG. Secondary patency rates for AVF at 1, 2 and 3 years were 77%, 71% and 69%, respectively. At the same time points, secondary patency rates for AVG were 77%, 60% and 46%, respectively (log rank P = 0.034). AVG required 2.4 times the number of interventions PPY than AVF. Surgical thrombectomy of AVG was at a rate of 0.49 PPY compared with 0.042 PPY for AVF.

CONCLUSION

AVG have a substantially higher rate of thrombosis than AVF, evident from early in the life of the graft. AVF demonstrate superior patency rates to AVG throughout the life of the access, with far fewer interventions PPY than grafts.