The Society for Vascular Surgery: Clinical practice guidelines for the surgical placement and maintenance of arteriovenous hemodialysis access

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.

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.

Association of anesthetic modality and other variables on 1-year functional patency of cephalic-based arteriovenous fistulae

OBJECTIVE

Some studies suggest that regional anesthesia provides better patency for arteriovenous fistula (AVF) for hemodialysis access as compared to local and general anesthesia. This study evaluates the impact of anesthetic modality on long term fistula function at 12 months.

METHODS

A retrospective review of patients undergoing cephalic vein-based hemodialysis access in consecutive cases between 2014 and 2019 was conducted from five safety net hospitals. The primary endpoint was functional patency at 12 months. Subset analysis individually evaluated cephalic-based lower forearm and wrist vs upper arm AVFs. Bivariate and multivariate logistic regression models evaluated the relationship between anesthetic modality and fistula function at 12 months.

RESULTS

There were 818 cephalic-based fistulas created during the study period. The overall 12-month functional patency rate was 78.7%, including an 81.3% patency for upper arm AVF and 73.3% for wrist AVF (P = .009). There was no statistically significant difference among patients with functional and nonfunctional AVFs at 12 months with respect to anesthetic modality when comparing regional, local, and general anesthesia (P = .343). Multivariate regression analysis identified that history of AVF/arteriovenous graft (odds ratio [OR], 0.24; P = .007), receiving intraoperative systemic anticoagulation (OR, 2.49; P < .001), and vein diameter (OR, 1.85; P = .039) as independently associated with AVF functional patency at 12 months.

CONCLUSIONS

There was no association between anesthetic modality and functional patency of cephalic-based AVFs at 12 months. Further studies are needed to better define which patients may benefit from regional anesthesia.

Comparison of pharmacological thrombolysis with mechanical thrombectomy in thrombosed arteriovenous fistulas and grafts: a systemic review and meta-analysis

AIM

To compare the effectiveness and safety of pharmacological thrombolysis and mechanical thrombectomy.

MATERIAL AND METHODS

This review was conducted in accordance with the PRISMA guidelines. Pooled proportions and subgroup analysis were calculated for primary and secondary patency rates, technical success, clinical success, major and minor complications rates.

RESULTS

This systematic review identified a total of 6,492 studies of which 17 studies were included for analysis. A total of 1,089 patients comprising 451 (41.4 %) and 638 (58.6 %) patients who underwent thrombolysis and mechanical thrombectomy procedures, respectively, were analysed. No significant differences were observed between thrombolysis and mechanical thrombectomy procedures in terms of technical success, clinical success, major and minor complications rates, primary and secondary patency rates; however, subgroup analysis of overall arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) demonstrated a significantly higher rate of major complications within the AVF group (p=0.0248).

CONCLUSION

The present meta-analysis suggests that pharmacological thrombolysis and mechanical thrombectomy procedures are similarly effective and safe; however, AVFs are subject to higher major complications compared to AVGs.

Computer-assisted image analysis of preexisting histological patterns of the cephalic vein to predict wrist arteriovenous fistula non-maturation

BACKGROUND

We used computer-assisted image analysis to determine whether preexisting histological features of the cephalic vein influence the risk of non-maturation of wrist fistulas.

METHODS

This study focused on patients aged 20-80 years who underwent their first wrist fistula creation. A total of 206 patients participated, and vein samples for Masson's trichrome staining were collected from 134 patients. From these, 94 patients provided a complete girth of the venous specimen for automatic image analysis. Maturation was assessed using ultrasound within 90 days after surgery.

RESULTS

The collagen to muscle ratio in the target vein, measured by computer-assisted imaging, was a strong predictor of non-maturation in wrist fistulas. Receiver operating characteristic analysis revealed an area under the curve of 0.864 (95% confidence interval of 0.782-0.946, p < 0.001). The optimal cut-off value for the ratio was 1.138, as determined by the Youden index maximum method, with a sensitivity of 89.0% and specificity of 71.4%. For easy application, we used a cutoff value of 1.0; the non-maturation rates for patients with ratios >1 and ≤ 1 were 51.7% (15 out of 29 patients) and 9.2% (6 out of 65 patients), respectively. Chi-square testing revealed significantly different non-maturation rates between the two groups (X2 (1, N = 94) = 20.9, p < 0.01).

CONCLUSION

Computer-assisted image interpretation can help to quantify the preexisting histological patterns of the cephalic vein, while the collagen-to-muscle ratio can predict non-maturation of wrist fistula development at an early stage.

Comparison of Open and Endovascular Aneurysm Repair in Native Arteriovenous Fistulas

BACKGROUND

Arteriovenous accesses develop aneurysms (FA) during their active use, resulting in pain, erosion, bleeding, and difficulty in cannulation. This study aims to evaluate the outcomes of open and endovascular management of single FA in arteriovenous fistulas (AVF).

METHODS

A retrospective review of all upper extremity primary AVFs over 12 years was undertaken at a single center. Patients undergoing elective open and endovascular repair of a single FA were identified. Thirty-day outcomes, cannulation failure, line placement, re-intervention, and functional dialysis (continuous hemodialysis) for 3 consecutive months were examined.

RESULTS

Three hundred and seventy nine patients presented with a single FA that met the requirements for intervention: 126 (33%) underwent endovascular repair, and the remainder 253 (67%) underwent open repair. Preoperative fistulogram identified anatomically significant issues in 91% of the cases, and these were treated by balloon angioplasty: 10% within the fistula tract, 44% within the outflow tract, and 47% in the central veins. In open repair, 57% underwent plication, 35% underwent resection and re-anastomosis, and the remainder (8%) underwent interposition grafting. In endovascular repair, successful placement of a stent was achieved in all cases with 1 ± 2 (mean ± standard deviation [SD]) covered stents (diameter: 6 -8 mm) placed, achieving successful exclusion of the FA. The combination of early thrombosis and cannulation failures led to the greater need for a tunneled central line in endovascular repair (6.5% vs. 2.4%; endovascular versus open repair; P = 0.04). As a result, the mean time for establishing renewed access in the index AVF was significantly higher in endovascular repair (2 ± 3 vs. 2 ± 2 weeks, mean ± SD; endovascular open repair versus open repair; P = 0.001). In follow-up, there were more secondary interventions per year in the endovascular compared to open repair groups (3.1 vs. 1.4 secondary interventions per year; endovascular versus open repair; P = 0.04). Median functional dialysis durations were superior in the open repair (48 ± 6%, mean + standard error) compared to the endovascular repair at 5 years. (26 ± 7%; P = 0.03).

CONCLUSIONS

Open repair results in a more rapid return to access use, lower need for a tunneled central line, lower secondary re-intervention rates, and superior functional dialysis durations compared to endovascular repair. Open FA repair should be considered for symptomatic single FA repairs before endovascular FA repair.

Carbon dioxide automated digital subtraction angiography for endovascular arteriovenous fistulas creation

Recent literature shows how residual renal function (RKF), defined as the urinary clearance of urea and creatinine, is associated with a lower mortality risk in HD patients. The use of non-nephrotoxic contrast media during radiological procedure, may be useful for preservation of RKF in patients with chronic kidney disease not yet in haemodialysis. We describe the case of a 51-year-old male suffering from chronic kidney disease from 2018, due to a right nephrectomy for an adenocarcinoma, who was considered for an endovascular arteriovenous fistula (endoAVF) creation (WavelinQ endoAVF System, Becton Dickinson, Franklin Lakes, New Jersey, US), using Carbon Dioxide as contrast media instead of conventional iodinated ones, with optimal results. CO2 DSA permits to well recognize the patency of target vein, its connection to the perforator vein and finally the endoAVF creation without requiring supplemental iodate contrast medium. We propose, CO2 automated digital subtraction angiography (DSA) as a safer technique that could be substitutive of the standard iodinated ones, in the creation of endo AVF.

Outcomes of one-stage and two-stage aneurysm repair in arteriovenous fistulae

OBJECTIVE

Maintenance of long-term arteriovenous access is important in long-term care for patients with end-stage renal disease. Arteriovenous access is associated in the long term with the development of fistula aneurysms (FAs). This study aims to evaluate the outcomes of staged FA treatment in dialysis access arteriovenous fistulae (AVF).

METHODS

A retrospective review of all patients over a 12-year period with primary autogenous AVF was undertaken at a single center. Patients undergoing elective open aneurysm repair were identified and were categorized into three groups: single FA repair (single, control group) and staged and unstaged repair of two FAs (staged and unstaged). A staged repair was a procedure in which the initial intent was to treat both aneurysms in the AVF and in which the most symptomatic aneurysm was treated first. When the incision from the first surgery had healed, the second symptomatic aneurysm in the AVF was treated. An unstaged repair was a procedure in which the initial intent was to repair both symptomatic aneurysms simultaneously. All patients had a fistulogram before the FA repair. Thirty-day outcomes, cannulation failure, line placement, reintervention, and functional dialysis (continuous hemodialysis for 3 consecutive months) were examined.

RESULTS

Five hundred twenty-seven patients presented with FA that met requirements for open intervention; 44% underwent single FA repair, whereas the remaining 34% and 22% underwent staged and unstaged repair of two FAs, respectively. The majority of patients were diabetic and Hispanic. Ninety-one percent of the patients required percutaneous interventions of the outflow tract (37%) and the central veins (54%). Thirty-day major adverse cardiovascular events were equivalent across all modalities. Thirty-day morbidity and early thrombosis (<18 days) were significantly higher in the unstaged group (4.3%) compared with the two other groups (1.3% and 2.1%, single and staged, respectively), which led to an increased need for a short-term tunneled catheter (8.9%) compared with the two other groups (3.4% and 4.4%, single and staged, respectively), Unstaged repair resulted in an increased incidence of secondary procedures (5.0%) compared with the two other groups (2.6% and 3.1%, single and staged, respectively). Functional dialysis at 5 years was equivalent in the single and staged groups but was significantly decreased in the unstaged group.

CONCLUSIONS

Open interventions are successful therapeutic modalities for FAs, but unstaged rather than staged repair of two concurrent FAs results in a higher early thrombosis, an increased secondary intervention rate, and a need for a short-term tunneled central line. Staged and single FA repairs have equivalent results. In the setting of two symptomatic FAs, staged repair is recommended.

Midterm outcomes of arteriovenous fistula aneurysm repair with simultaneous inflow revision or outflow tract revascularization

OBJECTIVE

The aim of this study was to investigate the 2-year outcomes of extensive revisions aimed at simultaneously addressing arteriovenous fistula (AVF) aneurysms, outflow stenosis, and/or high flow volumes.

METHODS

This was a retrospective cohort study in a tertiary referral center. The study population comprised hemodialysis patients with aneurysmal AVFs requiring revision. Subjects were eligible if they were ≥18 years of age and had aneurysm repair associated with inflow revision or treatment of outflow lesions. Patients were followed-up for a minimum of 2 years, and the primary outcome measure was cumulative patency.

RESULTS

Our cohort comprised 93 patients with a mean age of 56 ± 12 years. The most frequent access type was brachiocephalic fistula (61%), and the median access age at the time of revision was 66 months (interquartile range, 46-93 months). The median access flow volume was 2300 ml/min (interquartile range, 1281-2900), and 31 subjects (33%) presented aneurysms associated with both high flow and venous obstruction. Aneurysm repair consisted of aneurysmorraphy in the overwhelming majority (95%). Inflow revision was performed in a total of 49 cases (53%), and outflow tract obstruction was treated in 71 patients (72%), with 27 patients (29%) receiving a simultaneous 3-component revision. At 2 years, the primary, primary assisted, and cumulative patencies were 60% ± 1%, 91% ± 3%, and 94% ± 3%, respectively. The most frequent indication for first-time reinterventions was outflow tract stenosis (24%). Aneurysm recurrence was observed in 13 subjects (14%) during the entire follow-up and was responsible for reinterventions in seven of them (8%), with a 2-year freedom from aneurysm-related reintervention rate of 95% ± 3%.

CONCLUSIONS

Extensive AVF revision with simultaneous aneurysm repair, inflow revision, and outflow tract revascularization is feasible, safe, and associated with favorable 2-year patency rates.

Clinical characteristics and preoperative ultrasound parameters related to low patency in radio-cephalic arteriovenous fistulas

INTRODUCTION

Our objective is to describe the clinical characteristics and preoperative ultrasound mapping parameters associated with primary and secondary patency of radio-cephalic arteriovenous fistulas (RCF).

METHODS

A retrospective, single-center, descriptive study, including patients undergoing a RCF creation between 2015 and 2019. Socio-demographic data and ultrasound parameters were collected and an analysis of primary and secondary patency was performed.

RESULTS

Eighty-four patients were included in this study. Mean age was 65.6 (±13.9) years; 76.6% were male. Mean preoperative ultrasound parameters: forearm cephalic vein diameter was 2.8 (±0.57) mm, radial artery diameter was 2.6 (±0.42) mm, radial artery systolic peak velocity was 68 (±14.3) cm/s radial artery resistance index was 0.76 (±0.9). At the end of the 4 years the follow-up, the mean primary and secondary patency were 47.2% and 80% respectively. Only female sex was significantly associated with a decrease in both primary patency (p = 0.043, HR = 0.48) and secondary patency (p = 0.021, HR = 0.023). Furthermore, radial artery systolic peak velocity (p = 0.007, HR = 2.6) showed a significant association with decreased primary patency and forearm cephalic vein diameter showed a borderline significant association with decreased secondary patency (p = 0.046, HR = 8.2).

CONCLUSIONS

A standardized evaluation by a vascular surgeon or nephrologist represent a key in the preoperative assessment of AVF candidates. Based on our results, we will consider to avoid distal vascular access in both female patients with lower radial artery systolic peak velocity (less than 68 cm/s) and borderline forearm cephalic vein diameter (less than 2.8 mm) after initial assessment in our clinical practice. Our results could encourage new studies in order to stablish the potential role of these parameters in the RCFs patency rates.

Outcomes of upper arm axillary artery and brachial artery arteriovenous grafts

BACKGROUND

We compared the outcomes of upper arm arteriovenous grafts (AVGs) in a large, prospectively collected data set to determine if there are clinically significant differences in axillary artery-based and brachial artery-based AVGs.

METHODS

Patients who received upper arm AVGs within the Society of Vascular Surgery Vascular Quality Initiative (VQI) dataset were identified. The primary outcome measures were primary and secondary patency loss at 12-month follow-up. Other outcomes included were wound infection, steal syndrome, and arm swelling at 6-month follow-up. The log-rank test was used to evaluate patency loss using Kaplan-Meier analysis, and Cox proportional hazards models were used to examine adjusted association between inflow artery (brachial artery vs axillary artery) and outcomes, adjusting for configuration (straight vs looped).

RESULTS

Among 3637 upper extremity AVGs in the VQI (2010-2017), there were 510 upper arm brachial artery AVGs and 394 upper arm axillary artery AVGs. Patients with axillary artery AVGs were more likely to be female (72% vs 56%, p < 0.001) and underwent general anesthesia (61% vs 57%, p < 0.05). In univariable analysis, the 12-month primary patency (54% vs 63%, p = 0.03) and secondary patency (81% vs 89%, p = 0.007) were lower for axillary artery AVGs than upper arm brachial artery AVGs. In multivariable analysis, although wound infection and arm swelling were similar at 6-month follow up, axillary artery AVGs were more likely to have steal syndrome (adjusted Hazard Ratio (aHR) = 2.6, 95% Confidence Interval (CI) 1.2,5.6, p = 0.017). In addition, axillary artery AVGs were associated with higher rates of 12-month primary patency loss (aHR = 1.6, 95% CI 1.2-2.2, p = 0.002) and 12-month secondary patency loss (aHR = 2.0, 95% CI 1.3-3.3, p = 0.005).

CONCLUSIONS

From this observational study analyzing the outcomes of upper extremity hemodialysis access, axillary artery AVGs were associated with significantly lower patency rates and higher risk of steal syndrome than brachial artery AVGs.

Role of neutrophil extracellular traps in vascular access thrombosis in hemodialysis patients

BACKGROUND

A patent vascular access (VA) is a lifeline for hemodialysis (HD) patients. However, vascular access is prone to thrombosis, which, if left untreated, can lead to permanent VA loss and increased mortality. Neutrophil extracellular traps (NETs) are known to be involved in intravascular thrombosis. We evaluated the relationship between NETs and VA thrombosis and their impact on VA prognosis.

METHODS

A total of 189 patients with VA flow problems were enrolled. Among these, 93 patients underwent percutaneous transluminal angioplasty (PTA) for stenosis, and 96 patients underwent PTA with thrombectomy for thrombosis. Plasma nucleosome, myeloperoxidase-DNA complex, and von Willebrand factor (vWF) were measured as markers of circulating NETs and thrombosis risk, respectively. The primary outcome was permanent VA loss and the secondary outcome was recurrent thrombotic occlusion within 6 months. In addition, the presence of NETs in thrombi was evaluated by histopathological analysis.

RESULTS

Circulating nucleosome levels were closely associated with plasma vWF levels (r = 0.172, p = 0.025), and both were higher in thrombectomy cases than in PTA alone cases (nucleosome; 0.83 ± 0.70 vs. 0.35 ± 0.26, p < 0.001, vWF: 9.0 ± 7.6 vs. 7.3 ± 6.2, p = 0.038). The highest quartile of nucleosomes (Q4) was associated with an 18-fold increased rate of access thrombotic occlusion (p < 0.001). In addition, multivariate analysis showed that the rates of permanent access loss (HR 2.77, 95 % CI 1.35-5.77) and recurrent thrombosis (HR 2.35, 95 % CI 1.22-4.54) were much higher in patients with the Q4 nucleosome group than in those with Q1-3. In addition, higher neutrophil infiltration and NET expression in thrombi were also associated with poor VA prognosis.

CONCLUSIONS

Higher levels of circulating NETs and the amount of NET expression in thrombi may be associated with VA thrombosis and poor VA outcomes.

Functional Impairment is Associated with Poor Long-Term Outcomes after Arteriovenous Access Creation

BACKGROUND

Functional impairment affects outcomes after a variety of procedures. However, the impact of functional impairment on outcomes of arteriovenous (AV) access creation is unclear. We aimed to evaluate the association of patients' ability to ambulate and perform activities of daily living (ADL) with AV access outcomes.

METHODS

We retrospectively reviewed patients undergoing AV access creation at an urban, safety-net hospital from 2014 to 2022. We evaluated associations of impaired ambulatory and assisted ADL status with 90-day readmission, 1-year primary patency, and 5-year mortality.

RESULTS

Among the 689 patients receiving AV access, mean age was 59.6 ± 13.9 years, 59% were male, and 60% were Black. Access types included brachiocephalic (42%), brachiobasilic (26%), radiocephalic (14%), other autogenous (5%) fistulas, and prosthetic grafts (13%). Impaired ambulatory status was identified in 35% and assisted ADL status, when assessed, was identified in 21% of patients. Ninety-day readmission was more likely in patients with impaired ambulatory (58% vs. 39%, P < 0.001) and assisted ADL (56% vs. 41%, P = 0.004) status. On Kaplan-Meier analysis, 1-year primary patency was lower for patients with impaired ambulatory status (44% ± 3% vs. 29% ± 3%, P = 0.001), but was not significantly different for patients with assisted ADL status (41% ± 3% vs. 32% ± 5%, P = 0.12). Five-year survival was lower for patients with impaired ambulatory status (53% ± 5% vs. 74% ± 4%, P < 0.001), but was not significantly different for patients with assisted ADL status (45% ± 9% vs. 71% ± 4%, P = 0.1). On multivariable analysis, increased likelihood of 90-day readmission was significantly associated with impaired ambulatory status (odds ratio (OR) 2.03, 95% confidence interval (CI) 1.4-2.94, P < 0.001) and assisted ADL status (OR 1.66, 95% CI 1.07-2.57, P = 0.02). One-year primary patency was not significantly associated with impaired ambulatory (hazard ratio (HR) 1.25, 95% CI 0.98-1.6, P = 0.07) or assisted ADL status (HR 1.13, 95% CI 0.87-1.48, P = 0.36). Increased likelihood of 5-year mortality was associated with impaired ambulatory (HR 1.65, 95% CI 1.04-2.62, P = 0.04) and assisted ADL status (HR 2.63, 95% CI 1.35-5.11, P = 0.004).

CONCLUSIONS

Impaired ambulatory and assisted ADL statuses were associated with increased readmissions and long-term mortality after AV access creation. Approximately half of patients with functional impairment were not alive at 5 years. Setting outcome expectations as well as prospectively examining the impact of physical therapy and visiting nursing services for functionally impaired patients undergoing AV access creation are warranted.

Standardized Methodology for Duplex Ultrasound Examination of Arteriovenous Access for Hemodialysis: A Proposal of the French Society of Vascular Medicine and the French-Speaking Society of Vascular Access

Duplex ultrasound (DUS) is an essential tool for characterizing and monitoring arteriovenous (AV) access for hemodialysis. The aim of the work described here, requested by the French Society of Vascular Medicine in collaboration with the French-Speaking Vascular Access Society, is to propose a standardized methodology for performing and documenting DUS, taking into account the variety of AV access techniques and the problems routinely encountered. A steering committee reviewed the literature and selected the relevant references. A draft was prepared, and all items with missing or conflicting data were submitted to a Delphi consensus. The final document was discussed and approved by all participants. The principles of DUS evaluation of AV access consist of examination of the afferent artery, the anastomosis and the entire venous drainage system. DUS uses B-mode ultrasound, color flow, pulsed wave and power Doppler analysis. DUS can be used in a variety of clinical situations, which can directly influence the methodology of the examination and the interpretation of the results. Blood flow should be assessed as it correlates with the risk of thrombosis. The measurement should be adapted to the different anatomical and hemodynamic conditions encountered. Characterization of stenosis should take into account the residual diameter of the drainage vein and its hemodynamic consequences. Other complications can be assessed with a standardized DUS examination. When performed according to a rigorous methodology, DUS of the AV access allows a comprehensive assessment of its functionality and eliminates the need for further invasive diagnostic procedures.

Small Caliber Distal Cephalic Veins Undergo Significant Dilation under Anesthesia and Can Successfully Be Used for Arteriovenous Fistula Creation

BACKGROUND

Successful arteriovenous fistula (AVF) maturation and use for dialysis is highly dependent on preoperative diameter. Small veins (<2 mm) exhibit high failure rates and are typically avoided. This study investigates the effects of anesthesia on the distal cephalic vein diameter as compared to preoperative outpatient vein mapping for the purpose of hemodialysis access creation.

METHODS

One hundred eight consecutive procedures for dialysis access placement met inclusion criteria and were reviewed. All patients received preoperative venous mapping and postanesthesia ultrasound mapping (PAUS). All patients received either regional and/or general anesthesia. A multiple regression was conducted to determine predictors of venous dilatation. The independent variables included both demographical and operative-specific variables such as the type of anesthesia. Outcomes of fistula maturation (successful cannulation and dialysis) were analyzed.

RESULTS

In this cohort, the mean preoperative vein diameter was 1.85 mm and the mean PAUS diameter was 3.45 mm, a 2.21× increase, with only 2 patient veins failing to increase in diameter. Smaller veins (<2 mm) exhibited significantly more dilation than larger veins after anesthesia (2.73 vs. 1.47×, P < 0.001). In the multiple regression analysis, smaller vein diameter was correlated with a significantly greater degree of dilation (P < 0.001). The degree of venous dilation was not affected by patient demographic-specific factors or by the type of anesthesia (regional block versus general) in the multiple regression analysis. 6 month follow-up data for fistula maturation was available for 75 of 108 patients. Small veins (<2 mm) on preoperative ultrasound matured at a similar rate as larger veins (90% vs. 91.4%, P = 0.833).

CONCLUSIONS

Small caliber distal cephalic veins experience a significant degree of dilation under regional and general anesthesia and can successfully be used for AVF creation. Consideration should be made to perform a postanesthesia vein mapping for all patients undergoing access placement despite preoperative venous mapping results.

Early Follow-Up after Arteriovenous Fistula Creation is Associated with Improved Access-Related Outcomes

BACKGROUND

Up to 60% of arteriovenous fistulas (AVF) require intervention to assist maturation, which prolongs the time until it can be used for hemodialysis (HD). Current guidelines recommend early postoperative AVF examination to detect and address immaturity to decrease time to maturation. This study evaluates how the timing of postoperative follow-up to assess AVF maturity affects patients' outcomes.

METHODS

All patients who underwent AVF creation between 2017 and 2021 in an academic medical center were retrospectively reviewed, excluding patients lost to follow-up or not on HD. Outcomes were compared between patients that had delayed follow-up to assess AVF maturity, >8 weeks post surgery, versus early follow-up, <8 weeks post-surgery. AVF evaluation for maturity consisted of physical examination and duplex ultrasound. Primary endpoints were time to first cannulation (interval from AVF creation to first successful cannulation) and time to catheter-free dialysis (interval from AVF creation to central venous catheter removal).

RESULTS

A total of 400 patients were identified: 111 in the delayed follow-up group and 289 in the early follow-up group. The median time to follow-up was 78 days (interquartile range [IQR], 66-125) in the delayed follow-up group versus 39 days (IQR, 36-47) in the early follow-up group, (P < 0.0001). The maturation rate was 87% in the delayed follow-up group versus 81% in the early follow-up group, (P = 0.1) and both groups had similar rates of interventions to assist maturation (66% vs. 57%, P = 0.2). The early follow-up group had a significantly shorter median time to first cannulation (50 vs. 88 days; P < 0.0001) and shorter time to catheter-free HD (75 vs. 118 days; P <0.0001). At 4 months after AVF creation, the incidence of first cannulation was 74% in the early follow-up group versus 63% in the delayed follow-up group (P = 0.001). Similarly, the incidence of catheter-free dialysis was 65% in the early follow-up group versus 50% in the delayed follow-up group at 4 months postoperatively, (P = 0.036).

CONCLUSIONS

Early postoperative follow-up for evaluation of fistula maturation is associated with reduced time to first successful cannulation of AVF for HD and reduced time to catheter-free dialysis.

Surgical Referral for Hemodialysis Access Maintenance

Hemodialysis access is the lifeline for end-stage renal disease patients. However, dialysis access is associated with a host of complications, including thrombosis, recurrent stenosis, infection, aneurysmal changes and bleeding. Although endovascular therapy remains the first-line treatment owing to its less invasive nature, there are certain situations where surgical referral is recommended or even necessary. Regardless, management of dialysis access complications requires a multidisciplinary approach. Interventional radiologists should be familiar with the appropriate timing for surgical referral to better serve the complex patient population.

Management of Immature Arteriovenous Fistulas

In patients requiring long-term hemodialysis for chronic kidney disease, an arteriovenous fistula is the preferred mode of hemodialysis access over synthetic arteriovenous graft or hemodialysis catheters. The National Kidney Foundation recommended in their Kidney Dialysis Outcomes Quality Initiative (KDOQI) Clinical Practice Guidelines that the creation of an autogenous arteriovenous fistula should initially be sought whenever possible. In 2003, a program named the Fistula First Breakthrough Initiative was initiated in the U.S. to increase the use of arteriovenous fistula for hemodialysis and to ultimately surpass the goal of 50% fistula use in incident and 40% fistula use in prevalent hemodialysis patients per recommendation by KDOQI Guidelines. While this goal was achieved, the encouraged creation of arteriovenous fistulas saw a rise in fistulas that failed to mature. Researchers have focused on developing strategies to optimize fistula maturation. Studies have revealed that the presence of stenoses and accessory draining veins may contribute to unsuccessful fistula maturation. Endovascular treatment, including balloon angioplasty and accessory vein embolization, aim to correct anatomical factors that negatively affect the maturation process. This article reviews the techniques and outcomes of endovascular treatment in the management of immature fistulas.

A Comparative Study of Continuous Versus Interrupted Suturing Technique in Creating a Vascular Access for Hemodialysis: An Institutional-Based Experience

Background Arteriovenous fistulas (AVFs) are considered the first and best access for patients with end-stage renal disease who need permanent vascular access for hemodialysis over arteriovenous grafts and central venous catheters for reasons that have been well-established. Poor early patency rates pose the biggest challenge in creating vascular access as they cause increased morbidity and economic/psychological concerns among patients. To minimize such effects, it is critical to use a patient-centered approach and carefully choose patients for AVF access creation. This study aimed to compare the primary patency of distal vascular access provided by continuous suturing versus that provided by interrupted suturing. Methodology This prospective study was conducted in the urology department of a superspecialty, tertiary care center from November 2021 to November 2022. Patency was assessed immediately after surgery (on the table), one month later, and six months later by palpating thrill and auscultating bruit. A total of 50 patients between the ages of 18 and 70 years who met the inclusion criteria were randomly assigned to two groups of 25 each. Results The baseline characteristics of both groups were comparable. At six months (p = 0.09), the continuous suturing group was observed to be somewhat better than the interrupted suturing group, with no significant difference in immediate and one-month patency rates. When compared to the continuous suturing group, the primary patency failure rate was significantly higher in the interrupted suturing group. Conclusions Thus, under appropriate circumstances, continuous sutures can be performed with greater ease, resulting in anastomosis that is as patent as that performed with interrupted sutures.

Creating reverse flow arteriovenous fistulas with a forearm cannulation target

BACKGROUND

Establishing a forearm arteriovenous fistula (AVF) offers preferred cannulation sites and preserves proximal access opportunities. When a radiocephalic AVF at the wrist is not feasible and the upper arm cephalic and median cubital veins are inadequate, an AV graft or more complex access procedure is often required. Creating a retrograde flow forearm AVF (RF-AVF) is a valuable alternative where the mid-forearm median antebrachial or cephalic vein is adequate, offering forearm cannulation zones with AVF outflow through deep and superficial collaterals. We report our technique and results.

METHODS

We retrospectively reviewed our vascular access data base of consecutive patients during an 11-year study period where a RF-AVF established the only available cannulation target in the forearm. In addition to physical examination, all patients had ultrasound vessel mapping.

RESULTS

A forearm access was established with a RF-AVF as the only opportunity for cannulation in 48 patients. Ages were 14-86 years (median = 62 years). Forty-four percent female, 63% diabetic, 13% obese, and 29% had previous access operations. Inflow was proximal radial artery in 47 individuals and one proximal ulnar. Nine AVFs (19%) failed at 2-66 months (median 14 months). One RF-AVF was ligated due to arm edema. Follow-up was 2-111 months (median = 23.5 months). Primary and cumulative patency rates were 62% and 91% at 12 months, and 46% and 85% at 24 months. Five patients were lost to follow-up with functioning RF-AVFs (mean 41 months). Twenty-three patients (48%) died during F/U of causes unrelated to access procedures (mean 25 months).

CONCLUSIONS

Establishing a reverse flow forearm AVF offers a successful autogenous access option in the forearm for selected patients with an inadequate distal radial artery and/or cephalic vein at the wrist, avoiding more complex or staged procedures and preserving upper arm sites for future use. A proximal radial artery inflow procedure is recommended.

Imaging Patients with Kidney Failure

The approach to imaging a patient with kidney failure continues to evolve. Overstatement of the risk of iodinated contrast material-induced (ie, contrast-induced) acute kidney injury and new guidelines for administration of gadolinium-based contrast media affect screening and the choice of contrast material. Treatment of kidney failure requires dialysis or a kidney transplant. Pretransplant imaging includes assessment for the feasibility of performing a transplant and evaluation for underlying malignancy and peripheral vascular disease. Patients with kidney failure are at high risk for renal cell carcinoma. Subtypes that occur exclusively or more commonly in patients with kidney failure, such as acquired cystic kidney disease, renal cell carcinoma, and clear cell papillary renal cell carcinoma, have specific clinical-pathologic characteristics, with indolent behavior. Performing US for dialysis planning increases the success of placement of an arteriovenous fistula, while postoperative US evaluation is essential in assessment of access dysfunction. Systemic manifestations in patients with kidney failure are multifactorial and may relate to the underlying cause of renal failure or may be secondary to treatment effects. Disturbances in mineral and bone metabolism and soft-tissue and vascular calcifications are seen in patients with chronic kidney disease and mineral bone disorder. Neurologic and cardiothoracic complications are also common. The authors provide a comprehensive overview of imaging considerations for patients with kidney failure, including the appropriate use of CT, MRI, and US with their respective contrast agents; the use of imaging in transplant workup and dialysis assessment; and the common renal and extrarenal manifestations of kidney failure. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Arteriovenous fistula creation by nephrologist and its outcomes: a prospective cohort study from Vietnam

BACKGROUND

Arteriovenous fistula (AVF) is the gold standard vascular access for effective hemodialysis. There is a growing interest in AVF creations performed by nephrologists to help reduce vascular surgeons' workload and enhance the timely treatment of patients with end-stage renal disease (ESRD). However, little is known about the feasibility and effectiveness of this approach in the low-resource settings. We examined the AVF surgical success and failure rates and associated predictors as well as early complications of AVF creations by a trained nephrologist with supports from vascular surgeons in Vietnam.

METHODS

A prospective cohort study was conducted on all adult ESRD patients at the Hemodialysis Department of Thong Nhat Hospital between April 2018 and October 2020. Information on demographic characteristics, comorbidities, and AVF creations was collected using a standardized questionnaire. All patients were followed up until 18 weeks post-surgery.

RESULTS

Among 100 patients with a mean age of 61.22 ± 17.11 years old, male accounted for 54%. Common causes of ESRD included hypertension (57%) and diabetes (32%). Just more than half (52%) of them reported having an AVF creation prior to ESRD. The successful first-time AVF creation rate was 98% (13/99, 95%CI: 8.74-21.18%). The primary and secondary AVF failure rates were 13.13% (13/99, 95%CI: 8.74-21.18%) and 16.87% (14/83, 95%CI: 10.32-26.25%), respectively. Early complications included bleeding (1%) and early thrombosis of the anastomosis (2%). There was a statistically significant association between age and primary AVF failure (P = 0.005) and between operation time and secondary AVF failure (P = 0.038).

CONCLUSIONS

AVF creations performed by well-trained and skilled interventional nephrologists with supports from vascular surgeons can result in favorable short- and long-term outcomes. It is important to follow up older patients and those with a long operation time to detect AVF failures. A standardized AVF creation training program and practice for nephrologists is needed to increase successful rates.

Initiation of hemodialysis at one month following fistulogram in patients with advanced kidney disease

OBJECTIVE

Previous studies have demonstrated that low contrast volume used in access-related interventions had limited effects on the progression of chronic kidney disease (CKD) after fistulography, but studies are limited and heterogeneous. We sought to evaluate the rate of and factors associated with progression to dialysis (HD) within 1 month after fistulography for patients with advanced CKD.

METHODS

A single-institution retrospective cohort analysis of patients with CKD stage IV and V, not yet on HD, undergoing fistulography from 1 January 2014 to 31 December 2018 was performed. The primary outcome was progression to HD within 1 month. Additional variables and the association with the primary outcome such as medical comorbidities, contrast type or volume were assessed.

RESULTS

A total of 34 patients underwent 41 fistulograms prior to HD initiation. Progression to HD within 1 month of fistulogram occurred in seven patients (all CKD V). The mean time between fistulogram and HD was 271 days for 31 of 34 patients who ultimately progressed to HD. Those with CKD IV began HD in 549 days on average, while those with CKD V began HD in 190 days on average. Three patients had not initiated HD at a mean of 539 days of follow-up. The only factors associated with progression to HD within 1 month included use of isovue (p = .005) and elevated contrast volume, with a mean of 40 mL (p = .027).

CONCLUSION

Although none of the patients with CKD IV required HD within 1 month after fistulogram, the use of larger iodinated contrast volume was associated with progression to HD within 1 month of fistulography for patients with CKD V. Further studies should investigate the safety of iodinated and alternative (e.g., carbon dioxide) contrast media in fistulography or duplex-based HD access procedures for CKD patients, especially CKD V, not yet on HD.

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.

A Randomized Trial of Postoperative Handgrip Exercises for Fistula Maturation in Patients With Newly Created Wrist Radiocephalic Arteriovenous Fistulas

Introduction

We aimed to substantiate the benefit of postoperative handgrip exercises (HGEs) in enhancing the maturation of an arteriovenous wrist fistula.

Methods

We randomly assigned 119 patients aged 20 to 80 years who had wrist arteriovenous fistulas (AVFs) to undergo either a basic HGE program (group A), an advanced program (group B), or an advanced-plus upper arm banding program (group C). Outcomes were assessed by ultrasonographic evaluation of the diameter and flow at each follow-up. The attending nephrologist decided the clinical use of the fistula.

Results

We identified no significant differences among the HGE groups in the mean diameter and blood flow 14, 30, 60, and 90 days after the creation of the wrist AVF (P = 0.55, 0.88, 0.21, and 0.19 for the diameter; 0.94, 0.81, 0.49, and 0.56 for the flow, respectively). The intent-to-treat analysis also found no difference in the clinical use of fistulas for hemodialysis (HD) (P = 0.997).

Conclusion

In patients with a newly created wrist AVF, advancing frequency, with or without adding intensity using an upper arm tourniquet, of postoperative HGEs did not enhance the growth of the fistula or increase the rate of clinical use over 3 months. (ClinicalTrials.gov ID: NCT03077815).

Staged autogenous to prosthetic hemodialysis access creation strategy to maximize forearm options

OBJECTIVE

When an adequate cephalic vein is not available for fistula construction, surgeons often turn to basilic vein or prosthetic constructions. Single-stage forearm prosthetic hemodialysis accesses are associated with poor durability, and upper arm non-autogenous access options are often limited by axillary outflow failure, which inevitably drives transition to the contralateral arm or lower extremity. We hypothesized that initial creation of a modest flow proximal forearm arterial-venous anastomosis to dilate ("develop") inflow and outflow vessels, followed by a planned second-stage procedure to create a cannulation zone with a prosthetic graft in the forearm, would result in reliable and durable hemodialysis access in patients with limited options.

METHODS

We performed an institutional cohort study from 2017 to 2021 using a prospectively maintained database supplemented with adjudicated chart review. Patients without traditional autogenous hemodialysis access options in the forearm underwent an initial non-wrist arterial-venous anastomosis creation in the forearm as a first stage, followed by a second-stage interposition graft sewn to the existing inflow and venous outflow segments to create a useable cannulation zone in the forearm while leveraging vascular development. Outcomes included time from second-stage access creation to loss of primary and secondary patency, frequency of subsequent interventions, and perioperative complications.

RESULTS

The cohort included 23 patients; first-stage radial artery-based (74%) configurations were more common than brachial artery-based (26%). Mean age was 63 years (standard deviation, 14 years), and 65% were female. Median follow-up was 340 days (interquartile range [IQR], 169-701 days). Median time to cannulation from second-stage procedure was 28 days (IQR, 18-53 days). Primary, primary assisted, and secondary patency at 1 year was 16.7% (95% confidence interval [CI], 5.3%-45.8%), 34.6% (95% CI, 15.2%-66.2%), and 95.7% (95% CI, 81.3%-99.7%), respectively. Subsequent interventions occurred at a rate of 3.02 (IQR, 1.0-4.97) per person-year, with endovascular thrombectomy with or without angioplasty/stenting (70.9%) being the most common. There were no cases of steal syndrome. Infection occurred in two cases and were managed with antibiotics alone.

CONCLUSIONS

For patients without adequate distal autogenous access options, staged prosthetic graft placement in the forearm offers few short-term complications and excellent durability with active surveillance while strategically preserving the upper arm for future constructions.

Effect of primary balloon angioplasty on draining vein diameter and volume flow in patients with arteriovenous fistula: A cohort study

Background

Chronic kidney disease (CKD) and end-stage kidney disease (ESKD) cause major morbidity and mortality in 10% of the global population with CKD. The most common renal replacement therapy is hemodialysis with arteriovenous fistula (AVF) access. AVF often undergoes maturation failure due to feeding artery and draining vein inadequacy. Mechanical dilatation, such as primary balloon angioplasty (PBA), can overcome AVF maturation failure. The volume flow (VF) and diameter of the draining veins in AVF patients must be known to evaluate the effect of PBA on AVF maturation. This study aims to analyze the impact of PBA on VF and draining vein diameter in ESKD patients undergoing AVF surgery.

Methods

A retrospective cohort clinical trial was conducted at our institution. A total of 75 participants had AVF with an arterial diameter >1.5 mm or vein diameter at the AVF creation site of 2–4 mm. The subjects were divided into 2 groups: the intervention group undergoing PBA (n = 36) and the control group, without PBA (n = 39). PBA was performed using a Mustang ballon (3–6 mm, Medtronic). Follow-ups were conducted at 1 week, 2 weeks, and 6 weeks after AVF creation.

Results

Based on the data, the diameter and VF of the draining veins were significantly larger in the intervention group than in the control group (p < 0.001). Furthermore, we found significant differences in the mean diameter and VF of the draining veins between the control and intervention groups at all stages of examination, from preoperatively to 6 weeks postoperatively (p < 0.001). The strength of the analysis was more than 80%.

Conclusion

PBA can increase the diameter and VF of the draining veins in patients with AVF.

•

Mechanical dilatation (i.e., primary balloon angioplasty [PBA]) can prevent arteriovenous fistula (AVF) maturation failure.

•

Volume flow and diameter of draining veins in AVF patients must be known to evaluate the effect of PBA on AVF maturation.

•

PBA 1.5 × larger than nominal vein size can increase the diameter and volume flow of draining veins in the AVF procedure.

•

AVF with PBA 1.5 × larger than nominal vein size had a higher probability of AVF maturation than control.

Autogenous Vascular Access in American Indians

BACKGROUND

American Indians (AI) or Alaska Natives, or in combination with another race, comprised 6.8 million individuals in 2010 and the population is expected to exceed 10 million in the current census. Diabetes is more common in AIs than in other races in the United States and is responsible for 69% of new onset end stage renal disease in AI patients. The incidence of obesity is also higher among AIs. As both diabetes and obesity make creating a successful autogenous vascular access more challenging, we reviewed our experience creating arteriovenous fistulas in AI patients.

METHODS

Our vascular access database was reviewed for consecutive new AI patients undergoing creation of a hemodialysis vascular access during a 10-year period. Each patient underwent ultrasound vessel mapping by the operating surgeon in addition to history and physical examination. The goal for initial cannulation was 4-6 weeks after access creation. Minimal AVF flow volume for cannulation was 500 mL/min with an outflow vein diameter of 6 mm.

RESULTS

235 consecutive new AI patients were identified. All patients had an autogenous access constructed. The median age was 56 years (range, 15-89 years). Diabetes was present in 85% and 42% were female. Obesity was noted in 27% of the patients and 37% had previous vascular access operations. Primary patency at 12 and 24 months was 62% and 46%, respectively. Cumulative patency at 12 and 24 months was 96% and 94%, respectively. Female gender and previous access operations were associated with lower primary (P = 0.002 and 0.02, respectively) and cumulative patency (P = 0.01 and 0.04, respectively). Obesity was associated with lower cumulative access patency (P = 0.02). Overall, 74% of the access operations used the radial or ulnar artery for AVF inflow. Distal radial artery inflow AVFs were associated with longer patient survival (P = 0.01) and individuals with proximal radial inflow had longer survival when compared to brachial artery AVFs. Previous access operations were associated with shorter patient survival (P = 0.04).

CONCLUSIONS

Safe and functional arteriovenous fistulas can be created for American Indians despite a higher prevalence of vascular access risk factors such as diabetes and obesity.

Snuff-Box Versus Wrist Radiocephalic Arteriovenous Fistulas for Hemodialysis: Maturation Tend and its Affecting Factors

BACKGROUND

Thanks to its well proved long-term patency rates, native radiocephalic arteriovenous fistula remains the most commonly used vascular access type. Many articles had approached the criteria leading to a mature fistula. The aims of this work are to evaluate variables that may affect the maturation of distal fistulas and to determine if wrist fistulas have less risk of maturation failure than the snuff-box fistulas.

METHODS

We recorded all distal radiocephalic fistulas that had been created from January 2018 to February 2021. Epidemiological and clinical profile of patients, characteristics of performed fistulas and per and post-operative data were recorded and analyzed.

RESULTS

From January 2018 to February 2021, 165 upper limb vascular accesses for hemodialysis had been created including 47 (28.5%) distal radiocephalic fistulas. Among the latter, 39 (83%) fistulas were performed at the wrist and 8 (17%) at snuff-box area. There were 34 men (72.3%). Mean age was 67 years (37-87). Both types of fistulas had approximately an identic frequency of primary maturation failure (50% for radiocephalic versus 47.2% for snuff-box fistulas). Secondary maturation had been achieved in 9 fistulas. Patients with medical history of dyslipidemia, peripheral arterial disease (PAD), central catheter placement, and bad quality of vessels tend to develop an immature fistula.

CONCLUSIONS

No significant differences in maturation tend between snuff-box and wrist fistulas had been demonstrated. Thus, it seems reasonable to privilege the creation of the most distal fistulas allowing preservation of wrist fistulas as a second option in case of snuff-box fistulas maturation failure. However, selection of the most suitable cases for snuff-box fistulas creation, based on clinical and duplex ultrasound data, remains primordial.

Clinical Practices in Central Venous Catheter Mechanical Adverse Events

Background: Over 5 million central venous catheters (CVCs) are placed annually. Pneumothorax and catheter malpositioning are common adverse events (AE) that requires attention. This study aims to evaluate local practices of mechanical complication frequency, type, and subsequent intervention(s) related to mechanical AE with an emphasis on catheter malpositioning. Methods: This is a retrospective review of CVC placements in a tertiary hospital setting from 1/2013 to 12/2013. Pneumothorax and CVC positioning were evaluated on post-insertion chest x-ray (CXR). Malposition was defined as unintended placement of the catheter in a vessel other than the intended superior vena cava on CXR. Catheter reposition was defined as radiographic evidence of a new catheter with removal of the old catheter less than 24hrs after initial placement. Data points analyzed included pneumothorax and thoracostomy rate, CVC malposition frequency, catheter reposition rate, catheter duration, and incidence of complications such as catheter associated venous thrombosis. Result: Among 2045 eligible CVC insertions, pneumothoraces occurred in 14 (0.7%; 95%CI 0.38, 1.17) and malpositions were identified in 275 (13.4%; 95% CI 12.3, 15.3). The proportion of pneumothoraces that required tube thoracostomy was 57%. The proportion of CVCs with malposition that were removed or replaced within 24h was 32.7%. "Malpositioned" catheters that were left in place by the clinical team (n = 185) had an average catheter duration of 8.2 days (95% CI 7.2, 9.3) versus 7.2 days (95% CI 6.17, 8.23) for catheters that were replaced after initial malposition (p = 0.14, t test). The incidence of venous thrombosis in repositioned "malpositioned" catheters was 7.8% versus 4.9% for "malpositioned" catheters that were left in place. Conclusions: Clinically significant catheter malposition and pneumothorax after CVC insertion are low. In this study, replaced and non-replaced "malpositioned" catheters had similar catheter duration and rates of complications, challenging the current dogma of CVC malposition practice.

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.

Long Term Results from The Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access

PURPOSE

To report the five-year results from the Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access.

MATERIALS AND METHODS

Retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients followed a median 50 months (range 12-60). Data evaluated in the LTP group were fistula maturation and use, secondary procedures, and complications. Kaplan-Meier analysis of primary, primary assisted, cumulative patency, and functional patency (time from two-needle to abandonment) were performed for the ITT population.

RESULTS

In the LTP 99% (84/85) of fistulas were mature with 99% (78/79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (two-needle cannulation at prescribed rate, 2/3 sessions) was achieved in 92% (78/85) of patients, with seven patients never using their pAVF because not on dialysis (n=4), peritoneal dialysis (n=2), and refusing to use fistula (n=1). Fistula maintenance was required in 31.8% (27/85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year (PPPY) to maintain function and patency was 0.32 (91/288) for years 2-5. The cumulative patency was 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% years 1-5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during long-term follow-up CONCLUSION: Percutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. Continued use and evaluation of pAVF is warranted.

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.

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.

Elevation transposition method for superficialization of the basilic vein achieves better patency rate than tunnel transposition

OBJECTIVE

To compare the tunnel transposition and elevation transposition methods used for superficialization of the basilic vein in terms of complication and patency rates.

METHODS

This retrospective study included patients who underwent two-stage basilic vein transposition between August 2016 and December 2019. Patients were categorized into brachial-basilic fistula tunnel transposition (n=32) and elevation transposition (n=21) groups using medical records. Primary patency was defined as a conduit that remains patent without any re-intervention to maintain patency. Primary assisted patency was defined as a conduit that has undergone intervention to maintain patency but has never been thrombosed.

RESULTS

The distribution of baseline characteristics was similar between the two groups. Coronary artery disease was the only variable that was significantly different between the tunnel transposition and elevation transposition groups (31.1% vs. 4.8%, p=.035). The tunnel transposition group had a greater amount of blood loss (p<.001) and a longer period of hospitalization (p=.002) than the elevation transposition group. The rates of suture repair to stop bleeding from the conduit was significantly different between the tunnel transposition and elevation transposition groups (31.8% vs. 4.8%, p=.035), whereas those of other complications were not significantly different. The elevation transposition group had a significantly higher primary patency rate than the tunneled transposition group (p=.033); however, primary assisted patency was achieved in all patients (100%) in both groups.

CONCLUSION

Elevation transposition might be a more reliable method than tunnel transposition for superficialization of a basilic venous fistula.

Timing of the first cannulation and survival of arteriovenous grafts in hemodialysis patients: a multicenter retrospective cohort study

Arteriovenous graft (AVG) is an important vascular access route in hemodialysis patients. The optimal waiting time between AVG creation and the first cannulation is still undetermined, therefore the current study investigated the association between ideal timing for cannulation and AVG survival. This retrospective cohort study used data from the Taiwan National Health Insurance Database, which included 6,493 hemodialysis patients with AVGs between July 1^st 2008 and June 30^th 2012. The waiting cannulation time was defined as the time from the date of shunt creation to the first successful cannulation. Patients were categorized according to the waiting cannulation time of their AVGs as follows: ≤30 days, between 31 and 90 days, between 91 and 180 days, and >180 days. The primary outcome was functional cumulative survival, measured as the time from the first cannulation to shunt abandonment. The AVGs which were cannulated between 31 and 90 days (reference group) after construction had significantly superior functional cumulative survival compared with those cannulated ≤30 days (adjusted HR = 1.651 with 95% CI 1.482–1.839; p < 0.0001) and >180 days (adjusted HR = 1.197 with 95% CI 1.012–1.417; p = 0.0363) after construction. An analysis of the hazard ratios in patients with different demographic characteristics, revealed that the functional cumulative survival of AVGs in most groups was better when they received cannulation >30 days after construction. Consequently, in order to achieve the best long-term survival, AVGs should be cannulated at least 1 month after construction, but you should avoid waiting for >3 months.

Arteriovenous fistula maturation: Physical exam versus flow study

PURPOSE

The purpose of this study was to determine the utility of routine duplex flow study 4 to 6 weeks after primary AVF creation and to compare physical exam against a duplex flow study in predicting fistula maturation. A surveillance algorithm was established to evaluate the naïve fistula after primary creation.

METHODS

This was a single institution retrospective review of 155 veterans with primary autogenous AVF creation from 2016 to 2018. All patients received a duplex flow study evaluation after primary creation. A comparison was made between physical exam (PE) and flow study at 4 to 6 weeks post creation. Sensitivities and specificities of physical exam and duplex flow study were compared head-to-head in predicting unassisted fistula maturation. A mature AVF was defined as a fistula that could be repetitively cannulated and provided adequate flow for dialysis. Failure of maturation was defined as an AVF that was never usable for dialysis. An abnormal duplex included thrombosis, stenosis (> 50% on gray scale imaging), inadequate vein diameter (< 4 mm), inadequate vein length or superficialization, or poor flow (< 500 ml/min). Bivariate comparisons were conducted using Pearson's χ², Fishers exact test, and Wilcoxon test depending on distribution. Significance was defined as P < 0.05.

RESULTS

There were 53 patients with radiocephalic (RC) fistulas, 41 patients with brachiocephalic (BC) fistulas, and 6 patients with brachiobasilic (BB) fistulas. Of patients with a confirmed abnormal duplex ultrasound, 53% had an abnormal PE (sensitivity 53%; PPV 96.3%, P < 0.001). Of the patients with a confirmed normal duplex, 98% had a normal PE (specificity 98%; NPV 68.5%, P < 0.001). An abnormal duplex flow study had a 67% sensitivity for predicting AVF failure or need for reintervention while an abnormal physical examination had a 42% sensitivity in predicting AVF failure or need for reintervention (P < 0.001). In total, 48 fistulas needed reintervention, however only 20 (42%) were associated with an abnormal physical examination. Of those 48 reinterventions, 20 (42%) fistulas exhibited primary assisted maturation (P < 0.001). On duplex flow study alone, 32 patients had hemodynamically significant lesions necessitating reintervention, which went on to afford 9 (28%) primary assisted mature fistulas (P = 0.69).

CONCLUSION

Abnormal duplex flow studies have a better sensitivity for detecting AVF failure or the need for reintervention compared to physical exam alone. An abnormal duplex correlates more with needing a reintervention to achieve maturation than physical exam. Therefore, we advocate routine use of a postoperative duplex flow study to identify potentially correctable issues and optimize fistula maturation.

Access flow volume (Qa) and survival in a hemodialysis population: An analysis of 5208 Qa measurements over a 9-year period

BACKGROUND

Aim of the study was to determine associations between characteristics of arteriovenous access (AVA) access flow volume (Qa, mL/min) and four year freedom from cardiovascular mortality (4yr-CVM) in hemodialysis (HD) patients.

METHODS

HD patients who received a primary AVA between January 2010 and December 2017 in one center were analyzed. Initial Qa was defined as the first Qa value obtained in a well-functioning AVA by a two-needle dilution technique. Actual Qa was defined as access flow at a random point of time. Changes in actual Qa were expressed per 3-month periods. CVM was assessed according to the ERA-EDTA classification. The optimal cut-off point for initial Qa was identified by a receiver operating characteristic curve. A joint modelling statistical technique determined longitudinal associations between Qa characteristics and 4yr-CVM.

RESULTS

A total of 5208 Qa measurements (165 patients, male n = 103; age 70±12 years, autologous AVA n = 146, graft n = 19) were analyzed. During follow-up (Dec 2010-Jan 2018, median 36 months), 79 patients (48%) died. An initial Qa < 900 mL/min was associated with an increased 4y-CVM risk (HR: 4.05; 95% CI [1.94-8.43], P<0.001). After 4 years, freedom from CVM was 34% lower in patients with a Qa < 900 mL/min (53 ±7% vs. Qa ≥ 900 mL/min: 87 ±4%, P <0.001). An association between increases in actual Qa over 3-month periods and mortality was found (HR: 4.48 per 100mL/min, 95% CI [1.44-13.97], P =0.010) indicating that patients demonstrating increasing Qa were more likely to die. By contrast, actual Qa per se was not related to survival.

CONCLUSIONS

Studying novel arteriovenous access Qa characteristics may contribute to understanding excess CVM in HD patients.

Association Between Attempted Arteriovenous Fistula Creation and Mortality in People Starting Hemodialysis via a Catheter: A Multicenter, Retrospective Cohort Study

Background:

In North America, most people start hemodialysis via a central venous catheter (“catheter”). These patients are counseled to undergo arteriovenous fistula (“fistula”) creation within weeks of starting hemodialysis because fistulas are associated with improved survival.

Objectives:

To determine whether attempting to create a fistula in patients who start hemodialysis via a catheter is associated with improved mortality. We also sought to determine whether differences in baseline patient characteristics, vascular procedures for access-related complications, or days in hospital may confound or mediate the relationship between attempted fistula creation and mortality.

Design:

Multicenter, retrospective cohort study.

Setting:

Six dialysis programs located in Ontario, Alberta, and Manitoba.

Patients:

Patients aged ≥18 years who initiated hemodialysis via a catheter between January 1, 2004, and May 31, 2012, who had not had a previous attempt at fistula creation. We excluded those who had a life expectancy less than 1 year, who transitioned to peritoneal dialysis within 6 months of starting dialysis, and people who started hemodialysis via a graft.

Measurements:

Attempted fistula creation, all-cause mortality, patient characteristics and comorbidities, vascular procedures for access-related complications, and days spent in hospital.

Methods:

We used survival methods, including marginal structural models, to account for immortal time bias and time-varying confounding.

Results:

In total, 1832 patients initiated hemodialysis via a catheter during the study period and met inclusion criteria. Of these patients, 565 (31%) underwent an attempt at fistula creation following hemodialysis start. As compared to those who did not receive a fistula attempt, these people were younger, had fewer comorbidities, and were more likely to have started dialysis as an outpatient and to have received pre-dialysis care. In a marginal structural model controlling for baseline characteristics and comorbidities, attempted fistula creation was associated with a significantly lower mortality (hazard ratio [HR] = 0.53; 95% confidence interval [CI] = 0.43-0.66). This effect did not appear to be confounded or mediated by differences in the number of days spent in hospital or vascular procedures for access-related complications. It also remained similar in analyses restricted to patients who survived at least 6 months (HR = 0.60; 95% CI = 0.47-0.77) and to patients who started hemodialysis as an outpatient (HR = 0.48; 95% CI = 0.33-0.68).

Limitations:

There is likely residual confounding and treatment selection bias.

Conclusions:

In this multicenter cohort study, attempting fistula creation in people who started hemodialysis via a catheter was associated with significantly reduced mortality. This reduction in mortality could not be explained by differences in patient characteristics or comorbidities, days spent in hospital, or vascular procedures for access-related complications. Residual confounding or selection bias may explain the observed benefits of fistulas for hemodialysis access.

Trial Registration:

Not applicable (cohort study).

Outcomes of radiocephalic arteriovenous fistula in octogenarians

BACKGROUND

Current guidelines recommend radiocephalic arteriovenous fistula (RCAVF) as a first choice access for hemodialysis, without specific indication for octogenarians .This study was undertaken to assess the efficacy of RCAVF in octogenarians compared with younger patients.

MATERIAL AND METHODS

All patients treated by RCAVF from January 2013 to December 2017 were included in a prospective database for a retrospective analysis. Patient demographics, comorbidities, and dialytic treatment data were collected prospectively and compared in patients <80 year-old and ⩾80 years-old. Clinical surveillance was performed during each dialysis session. The main endpoints were primary (PP) and assisted patency (AP).

RESULTS

Within the study period, a total of 294 RCAVF were analyzed: 245 (83.3%) RCAVF were performed in <80 year-old and 49 (16.7%) ⩾80 years old. The overall PP and AP at 2-year was 69% ± 2% and 73% ± 3%, respectively. Patients ⩾ 80 years-old had a significantly reduced 2-year PP, AP of RCAVF compared with the younger patients: 50% ± 8% and 62% ± 7% versus 73% ± 3% and 75% ± 3%, p = 0.01 and p = 0.03, respectively.The analysis for possible risk factors for reduction of PP in patients ⩾80 years identified in the central venous catheter(CVC) a predictor of earlier RCAVF failure: HR 3.03(95% CI 1.29-7.13), p = 0.01.Kaplan-Meier curve confirms the reduction of PP in ⩾80 years old patients at 2-year follow-up with previous CVC compared patients without history of CVC: 59% ± 10% versus 24% ± 11%, p = 0.01. A comparison between the two groups was made in order to evaluate the impact of previous history of CVC .In absence of a history of CVC use older patients had a similar 2-year PP compared with younger patients: 59% ± 10% versus 72% ± 4%, p = 0.46. Otherwise, the history of a previous CVC reduced significantly the 2-year PP in ⩾80 years old patients compared the younger: 24% ± 12% versus 75% ± 5%, p = 0.0001.

CONCLUSIONS

Despite lower overall primary and primary assisted patency, RCAVF are associated with satisfactory results also in octogenarians if performed in absence of history of CVC. Under these circumstances RCAVF can be considered a first choice treatment.

Medical adjuvant treatment to increase patency of arteriovenous fistulae and grafts

BACKGROUND

People with end-stage renal disease (ESRD) often require either the formation of an arteriovenous fistula (AVF) or an interposition prosthetic arteriovenous graft (AVG) for haemodialysis. These access sites should ideally have a long life and a low rate of complications (e.g. thrombosis, infection, stenosis, aneurysm formation and distal limb ischaemia). Although some of the complications may be unavoidable, any adjuvant technique or medical treatment aimed at decreasing complications would be welcome. This is the fourth update of the review first published in 2003.

OBJECTIVES

To assess the effects of adjuvant drug treatment in people with ESRD on haemodialysis via autologous AVFs or prosthetic interposition AVGs.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and ClinicalTrials.gov trials register to 6 August 2020.

SELECTION CRITERIA

Randomised controlled trials of active drug versus placebo in people with ESRD undergoing haemodialysis via an AVF or prosthetic interposition AVG.

DATA COLLECTION AND ANALYSIS

For this update, two review authors (IM, MFAK) independently selected trials for inclusion, extracted data, assessed risk of bias and assessed the certainty of the evidence according to GRADE. We resolved disagreements by discussion or consultation with another review author (ADS). The primary outcome was the long-term fistula or graft patency rate. Secondary outcomes included duration of hospital stay; complications such as infection, aneurysm formation, stenosis and distal limb ischaemia; and number of related surgical or radiological interventions.

MAIN RESULTS

For this update, one additional study was suitable for inclusion, making a total of 13 trials with 2080 participants. Overall the certainty of the evidence was low or moderate due to short follow-up periods, heterogeneity between trials, small sample sizes, and risk of bias due to incomplete reporting. Medical adjuvant treatments used in the included trials were aspirin, ticlopidine, dipyridamole, dipyridamole plus aspirin, warfarin, fish oil, clopidogrel, sulphinpyrazone and glyceryl trinitrate (GTN) patch.  All included studies reported on graft patency by measuring graft thrombosis. There was insufficient evidence to determine if there was a difference in graft patency in studies comparing aspirin versus placebo (odds ratio (OR) 0.40, 95% confidence interval (CI) 0.07 to 2.25; 3 studies, 175 participants; low-certainty evidence). The meta-analysis for graft patency comparing ticlopidine versus placebo favoured ticlopidine (OR 0.45, 95% CI 0.25 to 0.82; 3 studies, 339 participants; moderate-certainty evidence). There was insufficient evidence to determine if there was a difference in graft patency in studies comparing fish oil versus placebo (OR 0.24, 95% CI 0.03 to 1.95; 2 studies, 220 participants; low-certainty evidence); and studies comparing clopidogrel and placebo (OR 0.40, 95% CI 0.13 to 1.19; 2 studies, 959 participants; moderate-certainty evidence). Similarly, there was insufficient evidence to determine if there was a difference in graft patency comparing the effect of dipyridamole versus placebo (OR 0.46, 95% CI 0.11 to 1.94; 1 study, 42 participants, moderate-certainty evidence) and dipyridamole plus aspirin versus placebo (OR 0.64, CI 0.16 to 2.56; 1 study, 41 participants; moderate-certainty evidence); comparing low-intensity warfarin with placebo (OR 1.76, 95% CI 0.78 to 3.99; 1 study, 107 participants; low-certainty evidence); comparing sulphinpyrazone versus placebo (OR 0.43, 95% CI 0.03 to 5.98; 1 study, 16 participants; low-certainty evidence) and comparing GTN patch and placebo (OR 1.26, 95% CI 0.63 to 2.54; 1 study, 167 participants; moderate-certainty evidence). The single trial evaluating warfarin was terminated early because of major bleeding events in the warfarin group. Only two studies published data on the secondary outcome of related interventions (surgical or radiological); there was insufficient evidence to determine if there was a difference in related interventions between placebo and treatment groups. None of the included studies reported on the duration of hospital stay.  Most studies reported complications ranging from mortality to nausea. However, data on complications were limited and reporting varied between studies.

AUTHORS' CONCLUSIONS

The meta-analyses of three studies for ticlopidine (an antiplatelet treatment), which all used the same dose of treatment but with a short follow-up of only one month, suggest ticlopidine may have a beneficial effect as an adjuvant treatment to increase the patency of AVFs and AVGs in the short term. There was insufficient evidence to determine if there was a difference in graft patency between placebo and other treatments such as aspirin, fish oil, clopidogrel, dipyridamole, dipyridamole plus aspirin, warfarin, sulphinpyrazone and GTN patch. The certainty of the evidence was low to moderate due to short follow-up periods, the small number of studies for each comparison, small sample sizes, heterogeneity between trials and risk of bias due to incomplete reporting. Therefore, it appears reasonable to suggest further prospective studies be undertaken to assess the use of these antiplatelet drugs in renal patients with an AVF or AVG.

A Comparison of Outcomes Between Open and Endovascular Arteriovenous Access Creation for Hemodialysis

OBJECTIVE

Preliminary outcomes for percutaneous endovascular autogenous access (endoAVF) have shown promising results; however, comparisons with surgical cohorts in dialysis populations are lacking. This study compares autogenous arteriovenous access created with the EverlinQ endoAVF system with accesses created by conventional surgical technique with respect to functional and patency related outcomes.

METHODS

This is a multicenter, retrospective review of autogenous arteriovenous accesses entered into a prospective database. Patients receiving radiocephalic, brachiocephalic, or endoAVF arteriovenous accesses between 2014 -2019 were included. Autogenous access maturation, primary patency, secondary patency, steal syndrome, and re-interventions were collected and analyzed using standard statistical and survival analyses.

RESULTS

A total of 369 accesses were created during the study period, including 61 endovascular accesses, 171 radiocephalic accesses, and 137 brachiocephalic accesses (median follow-up 17 months; range 1 - 71 months). Maturation failure at the end of follow-up was 27±6%, 27±5%, and 18±4% for endovascular, radiocephalic, and brachiocephalic accesses, respectively (p =.049 for brachiocephalic vs. endovascular accesses). Primary patencies at 12 and 24 months were 42±5% and 32±7% for endovascular accesses, 43±4% and 24±4% for radiocephalic accesses, and 42±4% and 29±4% for brachiocephalic accesses (p=.906). Secondary patencies at 12 and 24 months were 68±6% and 60±7% for endovascular accesses, 75±3% and 67±4% for radiocephalic accesses, and 91±3% and 81±4% for brachiocephalic accesses (p=.006 for brachiocephalic vs. endovascular accesses). There were no statistically significant differences in ischemic steal syndrome (3.3%, 4.1% and 8.0%; p=.229) or total reinterventions/year (1.0±3.1, 0.9±1.8, and 1.2±1.8; p=.289) for endovascular, radiocephalic, or brachiocephalic arteriovenous accesses, respectively.

CONCLUSIONS

EndoAVF compare favorably with respect to maturation and patency compared with surgically created accesses in a real-world cohort. Outcomes and reintervention rates are similar to conventional radiocephalic arteriovenous accesses, but are inferior with respect to patency and maturation to brachiocephalic accesses.

Are continued policies of prioritizing native vascular access in patients on hemodialysis programs useful?

The guidelines recommend establishing native vascular access as opposed to prosthetic or catheter-based access despite information relating to its effectiveness being scarce from a patient-orientated perspective. We analyzed the effectiveness of a continued policy of native vascular access (CPNVA) in patients undergoing hemodialysis. A retrospective, observational study, including 150 patients undergoing hemodialysis between 2006 and 2012 at our center, and who underwent a CPNVA. Statistical analysis was based on treatment intention. In 138 patients (92%), the first useful access (FUA) was native, and in 12 patients (8%), it was prosthetic. In 50 patients (33.3%), more than one procedure had to be carried out in to order to achieve FUA. The probability of dialysis occurring via a FUA was 67.1% and 45.3% at 1 and 5 years respectively. Over the follow-up period (mean time = 30 months), 84 patients (56%) required repairs or new access, extending the effectiveness of the CPNVA to 88.3% and 73.2% at 1 and 5 years respectively. The effectiveness of the CPNVA was reduced if the patient: required a catheter initially (HR: 3.6, p = 0.007); in cases of initially elevated glomerular filtration rate (HR: 1.1, p = 0.040); in cases of history of previous access failure before FUA (HR: 3.9, p = 0.001); and in female patients (HR: 2.4, p = 0.031). The long-term effectiveness of a CPNVA is high. However, the percentage of patients requiring diverse procedures in order to achieve FUA and the need for re-interventions yield the necessity to optimize preoperative evaluation and postoperative follow-up.

Influence of Tunneled Hemodialysis-Catheters on Inflammation and Mortality in Dialyzed Patients

Older age and comorbidities in hemodialysis patients determines the use of tunneled catheters as vascular access despite their reported clinical and mortality disadvantages. This prospective matched study analyzes the impact of permanent catheters on inflammation and mortality in hemodialysis patients; We studied 108 patients, 54 with AV-fistula (AVF) and 54 with indwelling hemodialysis catheters (HDC) matched by sex, age, diabetes and time under renal-replacement therapy comparing dialysis efficacy, inflammation and micro-inflammation parameters as well as mortality. Cox-regression analysis was applied to determine predictors of mortality, HDC patients presented higher C-reactive-protein (CRP) blood levels and percentage of pro-inflammatory lymphocytes CD14+/CD16+ with worse dialysis-efficacy parameters. Thirty-six-months mortality appeared higher in the HDC group although statistical significance was not reached. Age with a Hazard Ratio (HR) = 1.06, hypoalbuminemia (HR = 0.43), hypophosphatemia (HR = 0.75) and the increase in CD14+/CD16+ monocyte count (HR = 1.02) were predictors of mortality; elder patients dialyzing through HDC show increased inflammation parameters as compared with nAVF bearing patients, although they do not present a significant increase in mortality when matched by covariates. Increasing age and percentage of pro-inflammatory monocytes as well as decreased phosphate and serum-albumin were predictors of mortality and indicate the main conclusions or interpretations.

Distribution of Flow in an Arteriovenous Fistula Using Reduced-Order Models

The creation of a communication between an artery and a vein (arteriovenous fistula or AVF), to speed up the blood purification during hemodialysis of patients with renal insufficiency, induces significant rheological and mechanical modifications of the vascular network. In this study, we investigated the impact of the creation of an AVF with a zero-dimensional network model of the vascular system of an upper limb and a one-dimensional model around the anastomosis. We compared the simulated distribution of flow rate in this vascular system with Doppler ultrasound measurements. We studied three configurations: before the creation of the AVF, after the creation of the AVF, and after a focal reduction due to a hyper flow rate. The zero-dimensional model predicted the bounds of the diameter of the superficial vein that respects the flow constraints, assuming a high capillary resistance. We indeed highlighted the importance of knowing the capillary resistance as it is a decisive parameter in the models. We also found that the model reproduced the Doppler measurements of flow rate in every configuration and predicted the distribution of flow in cases where the Doppler was not available. The one-dimensional model allowed studying the impact of a venous constriction on the flow distribution, and the capillary resistance was still a crucial parameter.

Dialysis associated steal syndromes. A narrative review

BACKGROUND

To review contemporary concepts in the genesis of Dialysis Access Steal Syndrome (DASS) and its current management.

METHODS

An electronic search of literature from 1960 to 2020 in Pubmed and the Cochrane library was conducted and practice guidelines were examined. Search terms included dialysis, steal, ischemia, access and ESRD. Clinical presentation, pathophysiology, risk factors, diagnostic techniques and management outcomes of extremity ischemia following dialysis access creation were reviewed.

RESULTS

Symptomatic steal occurs in 4-10% of patietns after creation of hemodialysis access creation. Risk factos include brachial based fistula, diabetes, female sex, coronary heart disease, cerebrovascular disease, tobacco use, age more than 60 and hypertension. Diagnosis is mainly clinical and can be aided by non invasive testing. Correction o finflow stenosis, Distal revasulatisation with interval ligation, revision using distal inflow or other techniques are useful for fistula preservation.

CONCLUSIONS

Dialysis associated steal syndromes have a complex haemodynamic causation. Clinical presentation is diagnostic; however when the diagnosis is uncertain adjunctive noninvasive perfusion tests, duplex and other imaging amy be required. Management is guided by anatomic, patient and disease-related considerations.