Editor's Choice – Vascular Access: 2018 Clinical Practice Guidelines of the European Society for Vascular Surgery (ESVS)

von Willebrand Factor: A Central Regulator of Arteriovenous Fistula Maturation Through Smooth Muscle Cell Proliferation and Outward Remodeling

Background Arteriovenous fistula (AVF) maturation failure is a main limitation of vascular access. Maturation is determined by the intricate balance between outward remodeling and intimal hyperplasia, whereby endothelial cell dysfunction, platelet aggregation, and vascular smooth muscle cell (VSMC) proliferation play a crucial role. von Willebrand Factor (vWF) is an endothelial cell-derived protein involved in platelet aggregation and VSMC proliferation. We investigated AVF vascular remodeling in vWF-deficient mice and vWF expression in failed and matured human AVFs. Methods and Results Jugular-carotid AVFs were created in wild-type and vWF^-/- mice. AVF flow was determined longitudinally using ultrasonography, whereupon AVFs were harvested 14 days after surgery. VSMCs were isolated from vena cavae to study the effect of vWF on VSMC proliferation. Patient-matched samples of the basilic vein were obtained before brachio-basilic AVF construction and during superficialization or salvage procedure 6 weeks after AVF creation. vWF deficiency reduced VSMC proliferation and macrophage infiltration in the intimal hyperplasia. vWF^-/- mice showed reduced outward remodeling (1.5-fold, P=0.002) and intimal hyperplasia (10.2-fold, P<0.0001). AVF flow in wild-type mice was incremental over 2 weeks, whereas flow in vWF^-/- mice did not increase, resulting in a two-fold lower flow at 14 days compared with wild-type mice (P=0.016). Outward remodeling in matured patient AVFs coincided with increased local vWF expression in the media of the venous outflow tract. Absence of vWF in the intimal layer correlated with an increase in the intima-media ratio. Conclusions vWF enhances AVF maturation because its positive effect on outward remodeling outweighs its stimulating effect on intimal hyperplasia.

Arteriovenous Hemodialysis Access Stenosis Diagnosed by Duplex Doppler Ultrasonography: A Review

Arteriovenous fistula (AVF) is currently the hemodialysis access with the longest life expectations for the patients. However, even the AVF is at risk for many complications, especially the development of stenosis. The latter can not only lead to inadequate hemodialysis but also lead to AVF thrombosis. Duplex Doppler ultrasonography is a very precise method, in the hands of experienced professionals, for the diagnosis of AVF complications. In this review, we summarize the ultrasound diagnostic criteria of significant stenoses and their indication for procedural therapy.

How to needle: A mixed methods study on choice of cannulation technique for arteriovenous fistula

AIMS AND OBJECTIVES

The aim of this study was to describe the basis for choosing a cannulation technique for arteriovenous fistula.

BACKGROUND

Four cannulation techniques are relevant to cannulating an arteriovenous fistula: rope ladder, area puncture and buttonhole using blunt or sharp needles. The chosen technique may affect both the patency and number of complications.

DESIGN

The study used a convergent mixed methods design and inductive approach.

METHODS

A questionnaire and an inquiry of local guidelines were sent to nurses in all dialysis units in Sweden. Questionnaires were answered by nurses from 37 units, and 29 units included their local guidelines. The questionnaires were analysed using descriptive statistics and qualitative content analysis, and the guidelines were analysed using qualitative content analysis. The different analyses were combined in a final result. The study is based on GRAMMS guidelines.

RESULTS

Local guidelines, patients' and nurses' own judgement, and consultation with colleagues were found to greatly influence the choice of cannulation technique. Buttonhole was the most preferred cannulation technique in the participating units and was favoured by nurses when choosing a cannulation technique. The process of choosing a cannulation technique was found to be influenced by the dedication to good cannulation technique and healthy arteriovenous fistulas, whether the technique is perceived as being easy to use and is expected to prevent complications and based on the experienced-based knowledge of each dialysis unit.

CONCLUSIONS

Choosing a cannulation technique is a process based on the nurse, local guidelines and the patient. Most dialysis nurses and units in Sweden consider buttonhole to be a good cannulation technique and use it as their standard technique.

RELEVANCE TO CLINICAL PRACTICE

The results provide insight into why cannulation techniques are chosen differently in different units. The results also show the importance of evidence in making decisions on cannulation technique.

Results of endovascular treatment of venous anastomotic stenosis in prosthetic arteriovenous for hemodialysis PTFE grafts. Comparative analysis between patent and occluded grafts

OBJECTIVE

To analyze the results of endovascular treatment of venous anastomotic stenosis (VAS) in humero-axillary arteriovenous grafts (HAG), comparing outcomes between patent and thrombosed HAG.

MATERIAL AND METHODS

A retrospective cohort study was made of endovascular treated patients because of a VAS in a HAG between January 2009 and December 2019. Group A: Thrombosed HAG secondary to a VAS. Group B: Patent HAG with a VAS detected during follow-up. Technical success was defined as residual stenosis after treatment <30%, and clinical success as satisfactory immediate dialysis after surgery. After ET a biannual clinical and ultrasound follow-up was performed.

STATISTICAL ANALYSIS

Survival analysis was performed for time-to-event data to assess patency.

RESULTS

Group A: 55 patients. Group B: 22. There were no significative differences in demographic and anatomical factors between groups. Technical and clinical success were 100% in group B and 94.5% and 91% respectively in group A. Primary patency at 1, 6 and 12 months was: Group A: 81.8%, 22.4% y 15.7% respectively. Group B: 100%, 85.9%, 76,4% (p < 0.001). Secondary patency at 1, 6 and 12 months was: Group A: 85.2%, 45.8% y 31.3% respectively. Group B 100%, 95.3%, 95.2% (p < 0.001). Use of non-covered stents was associated with an increased risk of occlusion (HR 2.669 IC 95% 1.146-6.216, p = 0.010).

CONCLUSION

A higher patency of EV performed on a patent HAG is expected. It is therefore advisable to develop surveillance programs that are capable to detect VAS before its occlusion.

A randomised control trial protocol of MuST for vascular access cannulation in hemodialysis patients (MuST Study): contributions for a safe nursing intervention

BACKGROUND

The vascular access preservation and the maintenance of a complication-free fistula remains an Achilles' heel of hemodialysis in chronic kidney patients due to its substantial contribution to the morbidity and mortality. Systematic studies in the area of examining cannulation practices, achieving complication-free cannulation, and strategies to improve fistula survival are needed. For this reason, we consider it essential to create and investigate new methodologies for approaching fistula in patients on regular HD. The Multiple Single Cannulation Technique (MuST) is based on the association between the rope-ladder (RL) using the arteriovenous vessel through progressive rotation, and the buttonhole (BH) since there are three specific cannulation sites for each cannulation day during the week. The MuST is simple to implement and seems to be a very promising technique in terms of patient safety. Previous studies already showed an arteriovenous fistula survival similar to RL but significantly higher than BH.

METHODS

This MuST study is a multicenter, prospective, non-blind, parallel-group, randomized controlled trial with the intervention group submitted to MuST and a control group undergoing the rope-ladder, up to 100 subjects for each group. Patients will be randomized 1:1 to one of two cannulation technique (CT), and the follow-up period of this study will be 12 months. Primary outcome is to evaluate the arteriovenous fistula survival rate at 12 months determined by the percentage of fistulas in use from the beginning of the study to the date of the first clinical intervention by angioplasty or vascular surgery, to maintain or restore patency (unassisted patency). Secondary outcome is to evaluate arteriovenous fistula survival rate at 12 month determined by the percentage of fistulas in use from the study start to the date of access abandonment due to dysfunction, patient abandonment, or death, treatment change modality or study end. We will also evaluate the assisted primary patency and include the following secondary outcomes associated with the cannulation technique: Infection, Hematoma, Aneurysm development, and pain.

DISCUSSION

The study will investigate whether fistula survival can be improved when using cannulation by MuST compared to the RL. MuST study will provide important information on fistula survival when cannulated by MuST but also information related to its use in fistulas previously cannulated by other CTs.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT05081648 registered on 18 October 2021.

The clinical outcome of balloon-assisted maturation procedure between autogenous radiocephalic fistula and brachiocephalic fistula in a single center experience

OBJECTIVE

Balloon-assisted maturation by an endovascular method plays an important role in treating an immature arteriovenous fistula. However, the results between radiocephalic fistula and brachiocephalic fistula were rarely reported. This retrospective study aimed to investigate the effectiveness and outcome of balloon-assisted maturation in different sites of autogenous arteriovenous fistulas.

METHODS

This single-center retrospective study included patients who underwent balloon-assisted maturation procedures from January 2015 to December 2016. Of 148 patients, 117 and 31 patients had a radiocephalic fistula and a brachiocephalic fistula, respectively. The primary outcome was balloon-assisted maturation success. Data regarding fistula lesions, balloon types and size, frequency of procedures, and maturation time were collected for balloon-assisted maturations. The secondary outcome was the patency of a fistula in the follow-up period.

RESULTS

No difference was observed in procedure of balloon-assisted maturation frequency between the radiocephalic and brachiocephalic fistula groups. The total success rate was 77.7%, without significant difference between radiocephalic and brachiocephalic fistula groups (81.20% vs. 64.50%; P=0.055). Within the procedures, the culprit lesion of juxta-anastomosis segment (73.5% vs. 25.5%, P<0.001) and arterial inlet (21.2% vs. 7.8%, P=0.04) were more common in the radiocephalic fistula group, whereas the venous outlet was more common in the brachiocephalic fistula group (88.2% vs. 57.7%, P<0.001). Both groups had an equivalent patency rate after the balloon-assisted maturation within the follow-up period (P=0.272).

CONCLUSIONS

Balloon-assisted maturation was an effective procedure for immature fistulas, without significant difference between the radiocephalic and brachiocephalic fistulas. Through the procedure, the culprit lesions causing non-maturation were found to be different between the two groups. The patency rate between the two groups after surgery seems to be equivalent within the follow-up period.

Customizable modification of banding with external stenting for arteriovenous fistula flow reduction

We performed a single-center retrospective study of prospectively collected data for all patients who had flow reduction surgery with FRAME FR between November 2020 and January 2021. Ten patients had arteriovenous fistula flow reduction surgery with this technique. One patient had a distal fistula, whereas nine were within the cubital fossa. In nine patients the device was applied over the postanastomotic arteriovenous fistula outflow vein and in one in the preanastomotic radial artery. Technical success was achieved in all patients with a median flow reduction from 2150 to 825 mL/min. There were no wound or device-specific complications.

Editor's Choice - European Society for Vascular Surgery Clinical Practice Guideline Development Scheme: An Overview of Evidence Quality Assessment Methods, Evidence to Decision Frameworks, and Reporting Standards in Guideline Development

OBJECTIVE

A structured and transparent approach is instrumental in translating research evidence to health recommendations and evidence informed clinical decisions. The aim was to conduct an overview and analysis of principles and methodologies for health guideline development.

METHODS

A literature review on methodologies, strategies, and fundamental steps in the process of guideline development was performed. The clinical practice guideline development process and methodology adopted by the European Society for Vascular Surgery are also presented.

RESULTS

Sophisticated methodologies for health guideline development are being applied increasingly by national and international organisations. Their overarching principle is a systematic, structured, transparent, and iterative process that is aimed at making well informed healthcare choices. Critical steps in guideline development include the assessment of the certainty of the body of evidence; evidence to decision frameworks; and guideline reporting. The goal of strength of evidence assessments is to provide well reasoned judgements about the guideline developers' confidence in study findings, and several evidence hierarchy schemes and evidence rating systems have been described for this purpose. Evidence to decision frameworks help guideline developers and users conceptualise and interpret the construct of the quality of the body of evidence. The most widely used evidence to decision frameworks are those developed by the GRADE Working Group and the WHO-INTEGRATE, and are structured into three distinct components: background; assessment; and conclusions. Health guideline reporting tools are employed to ensure methodological rigour and transparency in guideline development. Such reporting instruments include the AGREE II and RIGHT, with the former being used for guideline development and appraisal, as well as reporting.

CONCLUSION

This guide will help guideline developers/expert panels enhance their methodology, and patients/clinicians/policymakers interpret guideline recommendations and put them in context. This document may be a useful methodological summary for health guideline development by other societies and organisations.

Radio-cephalic fistula recovered with drainage to median basilic vein by straightening of the forearm cephalic vein: A case report

The distal arteriovenous fistula (AVF) has less complications and better patency than the proximal fistula, when it works properly. The complications of outflow of the fistula are complex, and it is necessary to analyze all solutions to solve the problem. We introduce a novel approach to solve outflow problems of a radio-cephalic AVF by straightening of the forearm cephalic vein with drainage into the median basilic vein.

Conditional catheter-related thrombosis free probability and risk-adapted choices of catheter for lung cancer

Background

Current predictive tools assess catheter‐related thrombosis (CRT) in patients with lung cancer in a static manner at a single time point of catheterization. The subsequent hazard changes over time are unknown. The conditional catheter‐related thrombosis‐free probability (CCFP) can provide dynamic information on continual CRT‐free expectations. This study aimed to assess the CCFP and hazard rates based on risk categories and various venous access devices (VADs).

Methods

This retrospective study reviewed 939 patients with lung cancer with peripherally inserted central venous catheters (PICCs) or central venous catheters (CVCs) identified at the National Clinical Research Center for Cancer between January 1, 2015 and December 31, 2018. The incidence of CRT has also been reported. Patients were stratified into low‐ and high‐risk groups according to multivariate Cox regression analyses. CCFP is defined as the CRT‐free probability given that patients have no CRT for a definite time.

Results

A total of 507 patients with PICCs and 432 patients with CVCs were included in this study. The 3‐month CCFP increased from 74.2% at catheter insertion to 93.6% at 3 months. The hazards of CRT in the first month were highest (16.4%) and slightly thereafter. The high‐risk group initially had a higher (21.4%) but significantly decreased CRT hazard after 2 months (8.3%), whereas the low‐risk group maintained a comparable lower risk hazard of less than 5% after 1 month. In the overall cohort, patients with CVCs had lower CRT probability than those with PICCs (HR, 1.76; 95% CI: 1.28–2.41; p < 0.01). Further analysis demonstrated that compared with PICCs, CVCs provided a CRT‐free benefit in low‐risk patients (p = 0.02) but not in high‐risk patients (p = 0.06).

Conclusions

CCFP increased, and the hazards of CRT decreased over time in a risk‐dependent manner in patients with lung cancer. These valuable dynamic data may help optimize risk‐adjusted choices of VADs and risk‐adjusted prophylactic anticoagulation strategies for patients.

Prone Position Facilitates Creation of Ulnar-Basilic Arteriovenous Fistula

Background: The distal ulnar-basilic arteriovenous fistula (UBAVF) is a rarely used alternative type of vascular access for haemodialysis. The location of the vein on the back aspect of the forearm forces an extremely uncomfortable external rotation of the upper limb during surgery when the patient is in a supine position. Methods: We present a new approach towards creating UBAVF, which involves placing the patient in the prone position, thus eliminating the aforementioned inconvenience. The procedure was performed and described in a 46-year-old patient with chronic kidney disease (CKD) due to diabetic nephropathy. In the period from September 2021 to December 2021, we created an additional three UBAVFs with such modifications. Results: All fistulas were patent both immediately after the procedure and 2 weeks after surgery. Conclusions: The prone position may improve the comfort of both the operator and the patient during the procedure. On top of this, it may have a positive impact on the quality of the arteriovenous anastomosis.

Impact of the COVID pandemic on vascular access creation for hemodialysis in 16 Spanish hemodialysis centers

Background

The coronavirus disease (COVID) pandemic has resulted in a major disruption in healthcare that has affected several medical and surgical specialties. European and American Vascular Societies have proposed deferring the creation of an elective vascular access (VA) [autologous or prosthetic arteriovenous fistula (AVF) or arteriovenous graft (AVG)] in incident patients on haemodialysis (HD) in the era of the COVID pandemic. The aim of this study is to examine the impact of the COVID pandemic on VA creation and the central venous catheter (CVC)-related hospitalizations and complications in HD patients dialyzed in 16 Spanish HD units of three different regions.

Methods

We compared retrospectively two periods of time: the pre-COVID (1 January 2019–11 March 2020) and the COVID era (12 March 2020–30 June 2021) in all HD patients (prevalent and incident) dialyzed in our 16 HD centres. The variables analysed were type of VA (CVC, AVF and AVG) created, percentage of CVC in incident and prevalent HD patients, CVC-related hospitalizations and complications (infection, extrusion, disfunction, catheter removal) and percentage of CVC HD sessions that did not reach the goal of Kt (>45) as a marker of HD adequacy.

Results

A total of 1791 VAs for HD were created and 905 patients started HD during the study period. Patients who underwent vascular access surgery during the COVID period compared with pre-COVID period were significantly younger, with a significant decrease in surgical activity to create AVFs and AVGs in older HD patients (>75 and >85 years of age). There was a significant increase in CVC placement (from 59.7% to 69.5%; P < 0.001) from the pre-COVID to the COVID period. During the COVID pandemic, a significantly higher number of patients started HD through a CVC (80.3% versus 69.1%; P < 0.001). The percentage of CVC in prevalent HD patients has not decreased in the 19 months since the start of the pandemic [414 CVC/1058 prevalent patients (39.4%)]. No significant changes were detected in CVC-related hospitalizations between the pre-COVID and COVID periods. In the COVID period, a significant increase in catheter replacement and the percentage of HD session that did not reach the HD dose objective (Kt > 45) was observed.

Conclusions

COVID has presented a public health system crisis that has influenced VA for HD, with an increase in CVCs relative to AVFs. A decrease in HD sessions that did not reach the HD dose objective was observed in the COVID period compared with a pre-COVID period.

Hemodialysis Arteriovenous Fistula Dysfunction: Retrospective Comparison of Post-thrombotic Percutaneous Endovascular Interventions with Pre-emptive Angioplasty

OBJECTIVES

We aimed to compare the clinical outcomes of pre-emptive angioplasty versus post-thrombotic percutaneous endovascular restoration of dysfunctional arteriovenous fistula (AVF).

METHODS

This retrospective study reviewed data from 80 patients who underwent 114 endovascular interventions for a malfunctioning AVF from July 2016 to August 2019. Stenotic AVFs were treated with pre-emptive angioplasty. Thrombosed AVFs were treated with percutaneous pharmacomechanical fibrinolysis with urokinase used only during the operation or continuously infused. The differences in patency rates were evaluated using Kaplan-Meier method. In addition, univariate and multivariate regression Cox models were used to determine influential factors on the post-intervention primary patency.

RESULTS

Post-thrombotic interventions and pre-emptive angioplasty yielded statistically similar rates in clinical success (100% vs 100%), anatomic success (94% vs 89%; p = .52), complication (4% vs 11%; p = .29), as well as postintervention primary, assisted primary and secondary patency (p = .80; .57; .57). The use of pre-emptive angioplasty was associated with reduced total cost (¥25108 vs ¥30833, p< .001). The patients who used urokinase only during the operation prolonged both the primary and assisted primary patency (p = .02; .002), while those with continuous infusion of urokinase had worst patency rates and high costs (¥39275 vs ¥25108 vs ¥27140, p< .001). Compared with the other locations, dysfunction in the anastomotic or juxta-anastomotic segment (HR = .41, p = .001) was associated with prolonged postintervention primary patency.

CONCLUSIONS

No clinical outcome differences was found between the post-thrombotic percutaneous endovascular interventions and pre-emptive angioplasty. However, pre-emptive angioplasty decreased access expenditure.

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.

New hemodynamic variables as predictors of arteriovenous fistula maturation

INTRODUCTION

Failure to mature of native arteriovenous fistula (AVF) assessed by image is not well documented.

METHODS

The aim of this study is to evaluate AVF maturation by Doppler ultrasound within 6 weeks after surgery and check for new hemodynamic variables as prognostic factors.

RESULTS

A total of 155 native AVFs were created in 3 years. Median age of patients was 71 years (60;79), with male gender predominance of 59.4% (n = 92). Diabetes was present in 60.6% (n = 94). AVF was created in distal forearm in 49.7% (n = 77). Un-assisted and overall maturation was of 67.1% (n = 104) and 83.9% (n = 130), respectively. Failure to mature occurred in 21.3% (n = 33) and primary failure in 9.7% (n = 15). In univariate analysis, preoperative variables such as diameter of artery (3.5 vs. 2.2 mm; p < 0.001) and pulsatility index (7.9 vs. 6.6; p = 0.055) were associated with failure to mature of AVF. Postoperative variables as Qa (994 vs. 401 mL/min; p < 0.001), resistance index (0.52 vs. 0.63; p < 0.001), pulsatility index (0.74 vs. 1.21; p < 0.001), and acceleration time (0.17 vs. 0.12; p < 0.001) also predicted an unfunctional AVF. Spearman correlation coefficient (r) was good for resistance index (-0.628) and pulsatility index (-0.707) in comparison with blood flow (Qa). In multivariate analysis, postoperative pulsatility index was an independent predictor of AVF dysfunction (OR: 16.5; p < 0.001).

CONCLUSIONS

Failure to mature was of 21.3%. Pulsatility index could be an important tool as new hemodynamic variable to predict failure to mature of native AVF.

Optimising Access Surgery in Senior Haemodialysis Patients (OASIS): study protocol for a multicentre randomised controlled trial

INTRODUCTION

Current evidence on vascular access strategies for haemodialysis patients is based on observational studies that are at high risk of selection bias. For elderly patients, autologous arteriovenous fistulas that are typically created in usual care may not be the best option because a significant proportion of fistulas either fail to mature or remain unused. In addition, long-term complications associated with arteriovenous grafts and central venous catheters may be less relevant when considering the limited life expectancy of these patients. Therefore, we designed the Optimising Access Surgery in Senior Haemodialysis Patients (OASIS) trial to determine the best strategy for vascular access creation in elderly haemodialysis patients.

METHODS AND ANALYSIS

OASIS is a multicentre randomised controlled trial with an equal participant allocation in three treatment arms. Patients aged 70 years or older who are expected to initiate haemodialysis treatment in the next 6 months or who have started haemodialysis urgently with a catheter will be enrolled. To detect and exclude patients with an unusually long life expectancy, we will use a previously published mortality prediction model after external validation. Participants allocated to the usual care arm will be treated according to current guidelines on vascular access creation and will undergo fistula creation. Participants allocated to one of the two intervention arms will undergo graft placement or catheter insertion. The primary outcome is the number of access-related interventions required for each patient-year of haemodialysis treatment. We will enrol 195 patients to have sufficient statistical power to detect an absolute decrease of 0.80 interventions per year.

ETHICS AND DISSEMINATION

Because of clinical equipoise, we believe it is justified to randomly allocate elderly patients to the different vascular access strategies. The study was approved by an accredited medical ethics review committee. The results will be disseminated through peer-reviewed publications and will be implemented in clinical practice guidelines.

TRIAL REGISTRATION NUMBER

NL7933.

PROTOCOL VERSION AND DATE

V.5, 25 February 2021.

Brachial artery transposition versus catheters as tertiary vascular access for maintenance hemodialysis: a single-center retrospective study

Some hemodialysis patients are not suitable for creation of an arteriovenous fistula (AVF) or arteriovenous graft (AVG). However, they can receive a tunneled cuffed central venous catheter (tcCVC), but this carries risks of infection and mortality. We aimed to evaluate the safety and effectiveness of brachial artery transposition (BAT) versus those of tcCVC. This retrospective study evaluated hemodialysis patients who underwent BAT or tcCVC placement because of severe heart failure, hand ischemia, central venous stenosis or occlusion, inadequate vessels for creating standard arteriovenous access, or limited life expectancy. The primary outcome was whole access circuit patency. Thirty-eight patients who underwent BAT and 25 who underwent tcCVC placement were included. One-year patency rates for the whole access circuit were 84.6% and 44.9% in the BAT and tcCVC groups, respectively. The BAT group was more likely to maintain patency (unadjusted hazard ratio: 0.17, 95% confidence interval: 0.05–0.60, p = 0.006). The two groups did not have significantly different overall survival (log-rank p = 0.146), although severe complications were less common in the BAT group (3% vs. 28%, p = 0.005). Relative to tcCVC placement, BAT is safe and effective with acceptable patency in hemodialysis patients not suitable for AVF or AVG creation.

Stent grafts improved patency of ruptured hemodialysis vascular accesses

This study aimed to compare stent graft with balloon tamponade for ruptured dialysis access during percutaneous transluminal angioplasty. Patients over an 8-year period (2010–2018) were identified from a database of 11,609 procedures. The primary endpoint was target lesion primary patency at 12 months. A total of 143 patients who had rupture dialysis access were enrolled, of whom 52 were salvaged by stent grafts and 91 were salvaged by balloon tamponade. The 6-month target lesion primary patency was greater in the stent graft group than in the balloon tamponade group (66.7% vs. 29.5%, P < 0.001). The benefit of stent grafts was sustained for 12 months (52.5% vs. 9.0%, P < 0.001). The stent grafts increased the median time from the index procedure to the next intervention in the ruptured area by 171 days (260 vs. 89 days) at 12 months. There was no significant difference in the access circuit patency rates at 6 months (25.5% vs. 19.8%, P = 0.203) and 12 months (12.0% vs. 5.8%, P = 0.052). The patency results of the stent grafts remained after the multivariable adjustment analysis. Compared to balloon tamponade alone, stent grafts provided superior target lesion primary patency at 6 and 12 months. The access circuit patency rates were similar.

Effects of Demographic and Clinical Character on Differences in Self-care Behaviour Levels with Arteriovenous Fistula by Haemodialysis Patients: An Ordinal Logistic Regression Approach

INTRODUCTION

Haemodialysis (HD) patients should be trained to develop self-care behaviors in order to prevent and preserve their arteriovenous fistula (AVF). The aim of this study was identifying the factors that affect the levels of self-care behavior with AVF by HD patients.

METHODS

A cross-sectional study was conducted involving 89 patients.

RESULTS

Self-care levels were negatively affected by patients' location (Azores) and positively affected by marital status, education, employment, AVF duration and absence of complications with the AVF. Concerning the management of signs and symptoms, self-care levels were negatively affected by patients' location. Regarding prevention of complications, self-care levels were negatively affected by age and marital status and positively affected by marital status, employment, CKD etiology, AVF duration and previous AVF.

CONCLUSION

Further studies are required in order to confirm whether the considered factors affect levels of self-care behaviors with AVF, or whether other factors are needed as well.

Value of a quantitative model of axillary venous blood flow spectrum for the detection of central venous stenosis in patients undergoing hemodialysis via radiocephalic arteriovenous fistula

Background

Central venous stenosis (CVS) of radiocephalic arteriovenous fistula (RCAVF) affects RCAVF function and longevity. Ultrasound screening for CVS is limited by acoustic window. Herein, we analyzed the quantitative axillary venous (AxV) spectrum in hemodialysis patients via RCAVF, and constructed central venous stenosis index (CVSI) model based on the spectrum parameters to early detect resting asymptomatic CVS.

Methods

From August 2017 to May 2021, stage 5 chronic kidney disease (CKD) patients dialysed via RCAVF at the First Affiliated Hospital of Fujian Medical University were included in this study. No CVS-related symptoms were found and the pulsation at the arteriovenous anastomosis was normal. However, the patients had the sensation of swelling in the ipsilateral upper limb during dialysis; the venous pressure advanced upon the completion of dialysis; or both (n=52). The inclusion criteria were as follows: (I) Ultrasound (US) showed that the temporal phases of the AxV spectrum were “normal”; and (II) CVS was confirmed by digital subtraction angiography (DSA). The exclusion criteria were as follows: (I) stent placement; (II) multiple stenosis; and (III) placement of central venous catheter. A total of 37 patients participated in the analysis. Eighteen patients were included in the CVS group, and 19 cases without CVS were included in the control group. Independent sample t-test was used to screen each parameter of the AxV spectrum, and a CVSI model was constructed by principal component analysis (PCA). The receiver operating characteristic curve (ROC) was applied to analyze the diagnostic value of CVSI.

Results

According to the independent sample t-test, 9 parameters were found to have statistical significance (all P<0.05); they were analyzed by PCA, and the CVSI model was constructed. The ROC showed that CVSI had diagnostic value for CVS. When the cut-off value of CVSI was 7.13, the maximum value of the Youden index was 0.842, with a sensitivity of 100% and a specificity of 84.2%.

Conclusions

The CVSI helps to early detect resting asymptomatic CVS and dramatically increases the detection rate of CVS.

Supraclavicular brachial plexus and paravertebral blocks: novel regional anaesthetic technique for brachioaxillary fistula formation with a synthetic graft

Vascular access formation surgery for renal replacement therapy can be performed under local, regional or general anaesthesia. Regional anaesthesia may offer several advantages, however the sensory innervation to the upper medial arm can be difficult to adequately block. We describe a novel regional anaesthetic technique using both supraclavicular brachial plexus and paravertebral blocks for a multimorbid 73-year-old woman undergoing brachioaxillary fistula formation with a synthetic graft. An ultrasound-guided supraclavicular brachial plexus block was performed, followed by an ultrasound-guided T2/3 level paravertebral block. Adequate sensory blockade for surgery was achieved. Supplemental local anaesthetic infiltration was not required, and the operation was well tolerated by the patient. We consider this to be a valuable regional anaesthetic technique for vascular access formation surgery involving the upper arm.

Superficial femoral vein transposition as a solution for hemodialysis vascular access

Abstract The significant growth in the number of individuals dependent on hemodialysis for renal replacement therapy and unrestricted use of short and long-term catheters have challenged vascular surgeons in search of solutions for patients whose options for access via the upper limbs have been exhausted and for the increasing rates of central venous stenosis in these patients. When access via the upper limbs is impossible, exceptional techniques can be used and the lower limbs offer feasible alternative vascular access sites for hemodialysis. This article reports a case of superficial femoral vein transposition to make a loop arteriovenous fistula in a patient with no possibility of access via the upper limbs and presents a literature review on this technique that remains little used.

A cost-effectiveness analysis of the introduction of a specialised consultation with duplex ultrasound assessment prior to vascular access surgery for haemodialysis

INTRODUCTION

Duplex ultrasound (DUS) is increasingly used before vascular access (VA) surgery for haemodialysis. However, the cost-effectiveness of this approach is unknown. Our objective was to assess whether the introduction of a specialised consultation with DUS assessment modifies the cost and the time delay to achieve a first VA valid for haemodialysis.

PATIENTS AND METHODS

Prospective cohort of patients undergoing a first VA (June 2014-July 2017) after a specialised consultation with DUS (ECO group). They were compared with a historical cohort (January 2012-May 2014) where VA was indicated exclusively by clinical evaluation (CLN group). We analysed the cost related to visits, DUS assessments, interventions, hospital admissions and graft materials to achieve a first VA valid for haemodialysis at least during 1 month.

RESULTS

86 patients in the CLN group were compared with 92 in the ECO group. Patients in the ECO group were younger (68.4 vs. 64.0 years; P=.038) but no other differences were seen among groups. The average cost to achieve a first AV valid for haemodialysis was significantly lower in the ECO group (2707 vs. 3347€; P=.024). There was a higher cost associated with DUS assessments in the ECO group yet the CLN group had a higher cost related to follow-up visits, successive surgical interventions, prosthetic material, days of hospital admission and catheters. The mean time needed to achieve a first AV valid for haemodialysis was also shorter in the ECO group (49.9 vs. 82.9 days, P=.002).

CONCLUSION

The introduction of a specialised vascular access consultation with DUS prior to VA surgery has reduced the cost necessary to achieve a first VA valid for haemodialysis. From the patient's point of view this has meant less interventions and hospital admissions and a shortening of the time delay.

Long-term outcomes of arteriovenous snuffbox fistulas for hemodialysis

OBJECTIVE

Autologous arteriovenous fistulas in the arm have been shown to be superior to all other types of arteriovenous access and should be placed as far distally as possible. The aim of the present study was to delineate the advantages of snuffbox fistulas (SBFs).

METHODS

From January 2007 through April 2017, first time or new arteriovenous fistula surgery was performed in 375 patients. If feasible, an SBF was chosen. The observation period ended in December 2019. The focus of the present study was on the patency rates, redo surgery, complications, and mortality rates.

RESULTS

SBFs were created in 236 patients (92 women and 144 men; mean age, 67 years; 46% with diabetes). Within the first 6 weeks, 11% of the fistulas had failed. The primary patency rates were 75%, 69%, 64%, 61%, 60%, and 58% after 1, 2, 3, 5, 7, and 9 years, respectively. The secondary patency rates were 86%, 83%, 80%, and 77% after 1, 2, 3, and 5 years, respectively. Age, sex, and the presence of diabetes mellitus had no effect on the primary patency rates. Patients with a right-sided SBF had significantly worse primary patency. Of the 236 patients, 154 (65%) had died during the observation period. The incidence of surgical site infection within the first 30 days and access-related ischemia during the observation period was <1%.

CONCLUSIONS

The results from the present study have shown that with suitable anatomic conditions, a SBF is a good choice for the creation of dialysis access. The patency rates were encouraging, and it offers the longest puncturable segment of the cephalic vein. Also, the rate of perioperative complications was low.

Superficialization methods of arteriovenous fistula in obese patients: a review of the literature: Arteriovenous fistula in obese patients

BACKGROUND

The creation of an arteriovenous fistula (AVF) in obese patients with end-stage-renal-disease, might not lead to a successful hemodialysis session, partly due to excess adipose tissue overlapping the enlarged vein. This review summarizes the available evidence on superficialization methods in studies dealing with obese patients.

METHODS

An English-language literature search was undertaken in the MEDLINE/SCOPUS databases looking for publications that described procedures of salvaging autologous arteriovenous access in upper extremities of obese patients. Perioperative outcomes including technical and clinical success, mean vein depth reduction, wound complications and patency rates were compared within all identified techniques.

RESULTS

We identified 12 prospective and 8 retrospective studies. A total of 1149 patients with a mean age 57.2 (range: 49-68) years and a mean BMI 35.8 (range: 28.2-40.8) kg/m² underwent mainly radial-cephalic and brachial-cephalic AVF superficialization procedures [transposition, 54%; elevation, 11.1%; lipectomy, 26.1%; liposuction, 2.4%; implantation of a venous window needle guide device, 6.4%]. Technical success was similar between all methods (≥ 96%). However, successful cannulation was lower after liposuction and elevation (81.5 and 78.1% respectively). Transposition achieved lower mean vein depth reduction and clinical success when compared with lipectomy (4.9mm vs 8.8mm and 90% vs 92,7% respectively). Transposition and liposuction had the lowest and highest complication rate respectively (1.6% vs 40.8%). Primary and secondary patency rates were lower with liposuction (51.8 and 76.6% respectively), while lipectomy and elevation achieved the highest primary patency rates (68.3% and 71.6% respectively) at 12 months.

CONCLUSIONS

In obese patients, all superficialisation techniques report high technical success rates. Although limited by the design of individual published studies and lack of a standard for reporting outcomes, these results lead to satisfactory postoperative and early outcomes. In aggregate, lipectomy and transposition are more clinically effective and more durable procedures.

FACTORS AFFECTING THE OUTCOME OF SYMPTOMATIC CAROTID STENOSIS SURGICAL TREATMENT IN A SINGLE CENTER SERIES

OBJECTIVES

The aim of this study is to evaluate the role of preoperative ischemic brain lesion (IBL) volume, assessed by Diffusion-weighted magnetic resonance brain imaging (DW-MRI) with RAPID® processing, and surgery timing in predicting post-operative neurological outcomes in symptomatic carotid stenosis (SCS) patients treated with carotid endarterectomy (CEA).

MATERIALS AND METHODS

All patients with SCS who underwent CEA between January 2010 and June 2020 were considered. IBLs ipsilateral to the stenosis were identified in the preoperative magnetic resonance brain (MRI). The volume was quantified in mL and correlated with 30-day rates of stroke and stroke/death by χ2 and receiver operating characteristic (ROC) curve.

RESULTS

134 patients were surgically treated for SCS during the entire study period. CEA procedures were defined as emergent, urgent, or elective if performed within 48 hours, between 48 hours and 14 days, or after 14 days from symptoms onset, respectively. Cumulative new ipsilateral stroke rate was 4,5%, with a statistically higher neurological complications in emergent patients compared to urgent and elective patients (10,6%, 1,47% and 0% respectively, p 0,039). ROC curve analysis showed a volume of 10 mL was predictive of postoperative stroke with 100% sensitivity and 80% specificity. A IBL volume >10mL was an independent risk factor for postoperative stroke. Infact, the perioperative neurological complication rate was significantly different in high-IBL volume patients (>10 mL) compared with low-IBL volume patients (<10 mL) (p 0,003) CONCLUSIONS: : The present study suggest that the optimal timing for CEA is between 48 hours and 14 days. Furthermore, the present study suggests that the presence of the IBL, by itself, is not definitively related with an unsatisfactory neurological outcome. However, an IBL higher than 10 mL should be as a reliable threshold value adverse neurological result in SCS patients.

Anaesthesia Choice for Creation of Arteriovenous Fistula (ACCess) study protocol : a randomised controlled trial comparing primary unassisted patency at 1 year of primary arteriovenous fistulae created under regional compared to local anaesthesia

INTRODUCTION

Arteriovenous fistulae (AVF) are the 'gold standard' vascular access for haemodialysis. Universal usage is limited, however, by a high early failure rate. Several small, single-centre studies have demonstrated better early patency rates for AVF created under regional anaesthesia (RA) compared with local anaesthesia (LA). The mechanistic hypothesis is that the sympathetic blockade associated with RA causes vasodilatation and increased blood flow through the new AVF. Despite this, considerable variation in practice exists in the UK. A high-quality, adequately powered, multicentre randomised controlled trial (RCT) is required to definitively inform practice.

METHODS AND ANALYSIS

The Anaesthesia Choice for Creation of Arteriovenous Fistula (ACCess) study is a multicentre, observer-blinded RCT comparing primary radiocephalic/brachiocephalic AVF created under regional versus LA. The primary outcome is primary unassisted AVF patency at 1 year. Access-specific (eg, stenosis/thrombosis), patient-specific (including health-related quality of life) and safety secondary outcomes will be evaluated. Health economic analysis will also be undertaken.

ETHICS AND DISSEMINATION

The ACCess study has been approved by the West of Scotland Research and ethics committee number 3 (20/WS/0178). Results will be published in open-access peer-reviewed journals within 12 months of completion of the trial. We will also present our findings at key national and international renal and anaesthetic meetings, and support dissemination of trial outcomes via renal patient groups.

TRIAL REGISTRATION NUMBER

ISRCTN14153938.

SPONSOR

NHS Greater Glasgow and Clyde GN19RE456, Protocol V.1.3 (8 May 2021), REC/IRAS ID: 290482.

Percutaneous arteriovenous fistula creation

The first percutaneous systems used to create an arteriovenous fistula for hemodialysis were approved by the US Food and Drug Administration in 2018 and included the Ellipsys and WavelinQ devices. Early results and longer-term studies of these catheter-based devices suggest that they offer important benefits and potentially improved outcomes in patients with appropriate anatomy. The deep communicating vein in the cubital fossa and its relationship to the proximal radial artery or proximal ulnar artery are key vascular elements of both systems. The devices differ significantly in technical design, energy source, imaging requirements, procedure times, catheters, access vessel sites, and techniques. We review the two approved percutaneous arteriovenous fistula devices, including technical considerations, selecting the appropriate patient, postoperative evaluation, interventions, outcomes, potential complications, and cannulation issues.

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.

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

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

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

Cone-Beam CT and Image Fusion-Guided Percutaneous Recanalization of Occluded Central Venous Stent

We describe an 81-year-old man with end-stage renal disease and central venous occlusion who was referred for dialysis access creation. This case illustrates a novel percutaneous image fusion–guided recanalization of an occluded right subclavian vein and brachiocephalic vein stent in a patient with limited remaining dialysis access sites. (Level of Difficulty: Advanced.)

Validation of a novel ultrasound Doppler monitoring device (earlybird) for measurements of volume flow rate in arteriovenous fistulas for hemodialysis

BACKGROUND

Controversy exists regarding surveillance of arteriovenous fistulas for hemodialysis to increase patency. A significant reduction in volume flow rate (VFR) should lead to diagnostic evaluation and eventually intervention. Several methods are available for VFR measurements, but all of them are associated with low reproducibility. VFR trend analysis is suggested as an improved solution. It is therefore a need to find user-friendly, cost and time-effective modalities. We present a novel Doppler ultrasound device (earlybird) which could bridge this gap. It includes an easy-to-use and light-weight single element transducer.

METHODS

In an experimental and clinical setting, we compared earlybird to duplex ultrasound to assess VFR. In a closed circuit of blood-mimicking fluid, 36 paired calculations of calibrated, duplex ultrasound and earlybird VFR was measured. In addition, 23 paired recordings of duplex ultrasound and earlybird VFR was measured in 16 patients with underarm arteriovenous fistulas. Pearson correlation, intraclass correlation coefficient, root-mean-square and Bland-Altman plots were analyzed.

RESULTS

Strong correlation (r = 0.991, p < 0.001), and excellent level of agreement (ICC = 0.970 (95% CI 0.932 - 0.985), p < 0.001) between earlybird and the calibrated VFR was found in the experimental setup. This was confirmed in the clinical setting, with a strong correlation (r = 0.781, p < 0.001) and moderate to good level of agreement (ICC = 0.750 (95% CI 0.502-0.885), p < 0.001) between earlybird and duplex ultrasound VFR measured at the arteriovenous fistulas outflow veins. In the Bland-Altman plot-analysis for the experimental setup, we found smaller limits of agreement, a smaller consistent and proportional bias, as well as greater accuracy of earlybird than DUS when compared to the calibrated VFR.

CONCLUSION

Earlybird is a feasible tool for VFR measurements and could be a future promising device for easy assessment and surveillance of AVF for hemodialysis.

A critical review of surgical strategies to minimise venous stenosis in arteriovenous grafts

It is inevitable that complications arising from surgical procedures are ascribed to surgical technique, and this applies to venous stenosis (VS) in arteriovenous grafts. However, despite a wide range of cellular studies, computer modelling, observational series and clinical trials, there remains uncertainty on whether surgical technique contributes to VS. This article reviews evidence from basic science, fluid dynamics and clinical data to try and rationalise the main surgical options to modify the occurrence of venous stenosis. There is sufficient data from diverse sources to make recommendations on clinical practice (size of target vein, shape of anastomosis, angle of approach, distance from venous needling, trauma to the target vein) whilst at the same time this emphasises the need to carefully report the practical aspects of surgical technique in future clinical trials.

Development and Validation of a Machine Learning Model Predicting Arteriovenous Fistula Failure in a Large Network of Dialysis Clinics

Background: Vascular access surveillance of dialysis patients is a challenging task for clinicians. We derived and validated an arteriovenous fistula failure model (AVF-FM) based on machine learning. Methods: The AVF-FM is an XG-Boost algorithm aimed at predicting AVF failure within three months among in-centre dialysis patients. The model was trained in the derivation set (70% of initial cohort) by exploiting the information routinely collected in the Nephrocare European Clinical Database (EuCliD^®). Model performance was tested by concordance statistic and calibration charts in the remaining 30% of records. Features importance was computed using the SHAP method. Results: We included 13,369 patients, overall. The Area Under the ROC Curve (AUC-ROC) of AVF-FM was 0.80 (95% CI 0.79–0.81). Model calibration showed excellent representation of observed failure risk. Variables associated with the greatest impact on risk estimates were previous history of AVF complications, followed by access recirculation and other functional parameters including metrics describing temporal pattern of dialysis dose, blood flow, dynamic venous and arterial pressures. Conclusions: The AVF-FM achieved good discrimination and calibration properties by combining routinely collected clinical and sensor data that require no additional effort by healthcare staff. Therefore, it can potentially enable risk-based personalization of AVF surveillance strategies.

Expert consensus on the establishment and maintenance of native arteriovenous fistula

Vascular access is the lifeline of hemodialysis patients. There are great differences in the establishment and use of vascular access in different countries and regions around the world. We believe that on the basis of good evaluation and planning, it is recommended that hemodialysis patients choose native arteriovenous fistula first. In view of the new progress of vascular access views domestic and international at home and abroad in recent years, we organized experts to recommend the establishment and maintenance of arteriovenous fistula (AVF) for the Chinese population, including preoperative evaluation and planning of the establishment of AVF, AVF surgery, perioperative drug intervention measures and postoperative maintenance, and put forward suggestions for future research directions. The recommendations in this consensus are general and clinicians need to make treatment decisions based on the actual situation.

A Comparison of Clinical Outcomes of Endovascular Repair Versus Open Surgery for Ruptured Descending Thoracic Aorta

OBJECTIVE

The comparisons between thoracic endovascular aortic repair for ruptured thoracic aorta (TEVAR) and open surgery (OS) have not been well documented, although both procedures have been widely utilized. We performed a systematic review and meta-analysis to investigate the effectiveness and safety between TEVAR and OS in the repair of ruptured descending thoracic aorta.

METHODS

PubMed, Embase, and Cochrane Library databases were searched to find relevant studies to assess TEVAR and OS outcomes. The comparative parameters were perioperative mortality (30 day/in-hospital), 1 year mortality, paraplegia or paraparesis, renal insufficiency, stroke, pulmonary embolism, re-intervention rate, pulmonary complications, and cardiac complications. A fixed-effects model was applied to calculate the odds ratio (OR) with a 95% confidence interval (CI) on pooled outcomes from different studies.

RESULTS

Eighteen observational trials involving 2088 patients were evaluated (TEVAR=560; OS=1528). Meta-analysis showed that TEVAR in repairing the ruptured descending thoracic aorta was associated with lower perioperative mortality (OR=0.47; 95% CI: 0.34-0.66; p<0.01), 1 year mortality (OR=0.46; 95% CI: 0.29-0.75; p<0.01), renal insufficiency incidence (OR=0.56; 95% CI: 0.33-0.93; p=0.03), and pulmonary complications (OR=0.69; 95% CI: 0.52-0.92; p=0.01) when compared with OS. There was no significant difference between TEVAR and OS in terms of paraplegia, stroke, pulmonary embolism, cardiac complications, and early re-intervention rates. However, the late re-intervention rate was higher in the TEVAR group than that in the OS group.

CONCLUSIONS

When repairing the ruptured descending thoracic aorta, TEVAR may be performed rapidly and safely. TEVAR is associated with lower rates of perioperative morbidity and early postoperative complications than OS.

Initial Clinical Experience with a Symmetric Tip Tunneled Hemodialysis Catheter Without Side Holes

The purpose of this article is to assess the performance and safety of a novel, symmetric, side-hole-free tunneled cuffed catheter hypothesized to sustain adequate flow without the need for side holes. Between November 2016 and January 2019, Pristine hemodialysis catheters were placed de novo in 45 end-stage renal disease patients (27 males and 18 females) at a single investigational site. Forty-one catheters were placed in the right and four in the left internal jugular vein. There were no incidents of insertion failure. Patients had dialysis three times per week and were followed at four investigational sites. Nominal catheter flows, incidence of poor flow, and catheter-related infections were recorded at each dialysis session and analyzed. The average follow-up time was 161.69 days for a total of 7116 catheter days. Nine patients died from reasons unrelated to the catheter and one patient switched to fistula. Four patients had poor flows necessitating catheter replacement. Four patients had catheter-related bloodstream infections which resolved with antibiotics. These equate to 0.56 events per 1000 catheter days. Catheter survival was 100%, 97.6%, and 89.7% at 30, 90, and 180 days, respectively. The initial clinical assessment of the symmetric Pristine hemodialysis catheter featuring a Y-tip devoid of side holes revealed good catheter performance and survival and a low complication rate.

Gender Disparities in Vascular Access and One-Year Mortality among Incident Hemodialysis Patients: An Epidemiological Study in Lazio Region, Italy

(1) Background: Interest in gender disparities in epidemiology, clinical features, prognosis and health care in chronic kidney disease patients is increasing. Aims of the study were to evaluate the association between gender and vascular access (arteriovenous fistula (AVF) or central venous catheter (CVC)) used at the start of hemodialysis (HD) and to investigate the association between gender and 1-year mortality. (2) Methods: The study includes 9068 adult chronic HD patients (64.7% males) registered in the Lazio Regional Dialysis Register (January 2008–December 2018). Multivariable logistic regression models were used to investigate the associations between gender and type of vascular access (AVF vs. CVC) and between gender and 1-year mortality. Interactions between gender and socio-demographic and clinical variables were tested adding the interaction terms in the final model. (3) Results: Females were older, had lower educational level and lower rate of self-sufficiency compared to males. Overall, CVC was used in 51.2% of patients. Females were less likely to use AVF for HD initiation than males. 1354 out of 8215 (16.5%) individuals died at the end of the follow-up period. Interaction term between gender and vascular access was significant in the adjusted model. From stratified analyses by vascular access, OR female vs. male (AVF) = 0.65; 95% CI 0.48–0.87 and OR female vs. male (CVC) = 0.88; 95% CI 0.75–1.04 were found. (4) Conclusions: This prospective population-based cohort study in a large Italian Region showed that in females starting chronic HD AVF was less common respect to men. The better 1-year survival of females is more evident among those women with AVF. Reducing gender disparity in access to AVF represents a key point in the management of HD patients.

Distress Analysis of Mice with Cervical Arteriovenous Fistulas

Simple Summary

Functional hemodialysis access is essential for the survival of patients with end-stage renal disease. Although various guidelines recommend autologous arteriovenous fistula as the first choice for hemodialysis, it is still the Achilles heel for patients. Several in vivo models have been used to study and improve the mechanisms of vascular remodeling of arteriovenous fistula. However, some models have the disadvantage of having anatomical features or a hemodynamic profile different from that of the arteriovenous fistula in humans. In the presented cervical arteriovenous fistula model, these disadvantages were eliminated. It resembles the human physiology and is an ideal animal model for arteriovenous fistula research. Moreover, in order to understand the impact of this model on animal welfare, the distress of this new animal model was analyzed. Body weight, faecal corticosterone metabolites, burrowing activity, nesting behaviour and distress scores were analysed after fistula creation and during the following three weeks. The physiological, behavioural, and neuroendocrine assessments all indicated that this model causes only moderate distress to the animals. This not only meets the need for animal ethics but also improves the quality of scientific research. Therefore, this cervical model is suitable for arteriovenous fistula research and should be used more frequently in the future.

Abstract

The welfare of laboratory animals is a consistent concern for researchers. Its evaluation not only fosters ethical responsibility and addresses legal requirements, but also provides a solid basis for a high quality of research. Recently, a new cervical arteriovenous model was created in mice to understand the pathophysiology of arteriovenous fistula, which is the most commonly used access for hemodialysis. This study evaluates the distress caused by this new animal model. Ten male C57B6/J mice with cervical arteriovenous fistula were observed for 21 days. Non-invasive parameters, such as body weight, faecal corticosterone metabolites, burrowing activity, nesting activity and distress scores were evaluated at each time point. Six out of ten created arteriovenous fistula matured within the observation time as defined by an increased diameter. The body weight of all animals was reduced after surgery but recovered within five days. In addition, the distress score was significantly increased during the early time point but not at the late time point after arteriovenous fistula creation. Neither burrowing activity nor nesting behaviour were significantly reduced after surgical intervention. Moreover, faecal corticosterone metabolite concentrations did not significantly increase. Therefore, the cervical murine arteriovenous fistula model induced moderate distress in mice and revealed an appropriate maturation rate of the fistulas.

A national cohort study on hemodialysis arteriovenous fistulas after kidney transplantation - long-term patency, use and complications

OBJECTIVE

To describe the long-term hemodialysis arteriovenous fistula (AVF) patency, incidence of AVF use, incidence and nature of AVF complications and surgery in patients after kidney transplantation.

PATIENTS AND METHODS

We retrospectively analysed the AVF outcome and complications in all adult kidney allograft recipients transplanted between January 1st, 2000 and December 31, 2015 with a functional AVF at the time of transplantation. Follow-up was until December 31, 2019.

RESULTS

We included 626 patients. Median AVF follow-up was 4.9 years. One month after kidney transplantation estimated AVF patency rate was 90%, at 1 year it was 82%, at 3 years it was 70% and at 5 years it was 61%; median estimated AVF patency was 7.9 years. The main cause of AVF failure was spontaneous thrombosis occurring in 76% of AVF failure cases, whereas 24% of AVFs were ligated or extirpated. In a Cox multivariate model female sex and grafts were independently associated with more frequent AVF thrombosis. AVF was used in about one third of our patients. AVF-related complications occurred in 29% of patients and included: growing aneurysms, complicated thrombosis, high-flow AVF, signs of distal hypoperfusion, venous hypertension, trauma of the AVF arm, or pain in the AVF/arm.

CONCLUSIONS

AVFs remain functional after kidney transplantation in the majority of patients and are often re-used after graft failure. AVF-related complications are common and require proper care.